Plaques et mouvement
Dossier réalisé pour Eduterre-usages-IFE
par Marie-José Broussaud et Christine Cottard
Cette création est mise à disposition sous un contrat Creative Commons.

A propos de Google Earth
Ce qui s'affiche à l'écran est un S.I.G. : Système d' Informations Géoscientifiques, il permet:
- d'afficher des "couches" de données qui sont géographiquement localisées ( par leur lattitude et longitude) (ex : le volcan de La Fournaise)
sur une même couche différentes données peuvent être regroupées (ex: les volcans du monde) on peut donc
- superposer les données (couches géoréférencées)
- chercher si on peut ou non les relier entre elles

Aide à la navigation
Informations techniques à respecter:
1) Dans "Infos pratiques" ou "Données géographiques" : tout décocher puis cocher "Relief"
2) Modifier le facteur d'élévation afin de mieux voir le relief:
"Outils"/ Options... Facteur d'élévation = 2
3) Pour ouvrir un dossier cliquer sur +, un - apparait alors.
4)- Un clic sur le nom du dossier permet d'afficher un texte
- Deux clics permettent de se rendre au lieu désiré
Attention! ne jamais perdre le Nord
- pour voir le relief, 2 possibilités :
a) Enfoncer la touche "shift" et avec la molette de la souris changer l'angle de vision
b) Utiliser les contrôles de navigation.
5) Après chaque vision 3D se remettre à plat en utilisant le contrôle de navigation.
6) Au fur et à mesure, décocher les données non utilisées
7) Ne pas tenir compte de : en bas de certaines pages de
Itinéraire : Vers ce lieu - À partir de ce lieu
Pour se familiariser avec Google Earth:
dans le fichier kmz "volcans:localisation" commencer par "Observations et situations de quelques volcans"
8) En fermant Google Earth
ne pas enregistrer dans mes lieux préférés

La tâche à accomplir
Montrer que les volcans de l'archipel d'Hawaï indiquent ce que fait la plaque sur laquelle ils sont situés.

Les volcans :

Les volcans des îles d'Hawaï
volcans : données Volcano World site.

Holocène volcans

Kuril Islands

Golovnin
Kunashir Island
Volcano types:
Caldera
Lava domes
Summit Elev: 543 m
Latitude: 43.841°N
Longitude: 145.509°E
Golovnin volcano, the southernmost in the Kuril Islands, forms the southern end of Kunashir Island, across the Nemuro Strait from Hokkaido. Explosive activity has dominated in the formation of andesitic-dacitic Golovnin volcano; no lava flows are exposed. The gently sloping stratovolcano, also known as Tomari-yama, is truncated by a 4-5 km wide caldera that formed during a series of late-Pleistocene eruptions beginning about 43,00 years ago. Several lava domes were subsequently emplaced on the caldera floor. Topographic highs outside the caldera rim define a series of lava domes extruded along a ring structure or an outer caldera. A 1 x 2.5 km caldera lake on the northern side of the inner caldera drains through a narrow breach in the western caldera wall. Solfataric activity occurs at the northern lake shore and at explosion craters (one of which contains a hot crater lake with reported temperatures from 36-100 degrees Centigrade) that cut the caldera-floor lava domes. The only known historical eruption of Golovnin was a minor explosion in 1848.
About Volcano Data | Larger photo with caption and credit.
Smithsonian Volcano Information | Kamchatka Volcanic Eruption Response Team | Geological Survey of Japan

Mendeleev
Kunashir Island
Volcano types:
Stratovolcano
Caldera
Lava domes
Summit Elev: 888 m
Latitude: 43.976°N
Longitude: 145.736°E
Mendeleev, also known as Rausu-dake, is a low compound stratovolcano located in the southern part of Kunashir island. The dominantly andesitic-dacitic volcano is cut by two nested calderas, the larger 6-7 km in diameter and the smaller 3-3.5 km. A central cone that formed inside the younger caldera was breached to the west by a large debris avalanche about 4200 years ago. A lava dome that grew inside the avalanche scarp forms the 888 m high point of the volcano. Additional lava domes in the northern part of the older caldera are considered to represent flank activity of the younger caldera. The only unambiguous historical eruption was a small phreatic explosion in 1880. Four solfatara fields lie at the eastern and northern flanks of the central cone, and the Goriachy Pliazh geothermal field is located outside the caldera along the eastern coast.
About Volcano Data | Larger photo with caption and credit.
Smithsonian Volcano Information | Kamchatka Volcanic Eruption Response Team | Geological Survey of Japan

Smirnov
Kunashir Island
Volcano types:
Stratovolcano
Pyroclastic cones
Lava domes
Summit Elev: 1189 m
Latitude: 44.420°N
Longitude: 146.135°E
Smirnov is a gently sloping 1189-m-high stratovolcano, located immediately west of Tiatia volcano at the NW tip of Kunashir Island in the southern Kuriles. The northern flank of the andesitic volcano in part retains a constructional form, but the southern side has been heavily eroded by glaciers, exposing its Tertiary basement. A wide glacial trough on the SE flank contains a pyroclastic cone at its head that fed a 4-km-long lava flow. Another pyroclastic cone is located at the base of the trough near the terminus of the lava flow. Two fresh-looking lava domes of Holocene age also lie within the glacial valley to the north. On the NW side Smirnov overlaps the late-Pleistocene andesitic-to-dacitic Rurui volcano, which has an active fumarole field on its western flank.
About Volcano Data | Larger photo with caption and credit.
Smithsonian Volcano Information | Kamchatka Volcanic Eruption Response Team | Geological Survey of Japan

Tiatia
Stratovolcano
Caldera
Pyroclastic cones
Tiatia volcano, one of the most impressive of the Kuril Islands, consists of a beautifully symmetrical cone that rises above the broad rim of an erosionally furrowed, 2.1 x 2.4 km wide caldera. The 1819-m-high Tiatia (also known as Chacha-dake) occupies the NE tip of Kunashir Island and morphologically resembles Mount Vesuvius. The pristine-looking conical central cone, mostly formed by basaltic to basaltic-andesite strombolian eruptions, rises 400 m above the floor of the caldera and contains a 400 x 250 m wide crater with two explosion vents separated by a linear septum. Fresh lava flows cover much of the SW caldera floor and have overflowed the rim, extending to the foot of the older somma, which formed during the late Pleistocene or early Holocene. A lava flow from a flank cone on the northern caldera rim reached the Sea of Okhotsk. A major explosive eruption in 1973 was the first since Tiatia's initial historical eruption in 1812.

Berutarube
Iturup Island
Shield volcano
The gently sloping, 1220-m-high Berutarube stratovolcano forms the SW tip of Iturup Island. The flanks of the andesitic-to-dacitic volcano are deeply dissected by wide glacial valleys; a low saddle on the NE side separates Berutarube from the slopes of Lvinaya Past caldera. The only known Holocene activity at Berutarube produced a small pyroclastic cone that was superposed on the intersecting headwalls of U-shaped valleys and cirques on the volcano's broad eroded summit. The hydrothermally altered summit cone was the source of two small lava flows. Berutarube was estimated to have ceased erupting only a few hundred to at most 1000 years ago (Gorshkov, 1970). No confirmed historical eruptions of Berutarube are known, although fumarolic areas on the walls of the summit crater are currently depositing sulfur.

Lvinaya Past
Iturup Island
The rim of the dramatic 7 x 9 km wide Lvinaya Past (Lion's Jaw) caldera on southern Iturup Island drops to 50 m below sea level on the NW side. The volcano derives its name from a rock resembling a sleeping lion that breaches the surface at the center of the submerged caldera rim. A shallow 5-km-wide passageway on the NW side allows access of the Sea of Okhotsk into the caldera basin, whose floor is 550 m below sea level and lies almost 1 km below the caldera rim. The caldera, also referred to as Moikeshi, formed about 9400 years ago during one of the largest Holocene eruptions of the Kuril Islands. Thick dacitic pumice deposits from this eruption form the 50-60 m high Yuzhny (Southern) isthmus, which joins the three southernmost volcanoes on Iturup Island, Rokko, Lvinaya Past, and Berutarube.

Atsonupuri
Iturup Island
Conical Atsonupuri stratovolcano forms a prominent peninsula joined to the SW side of Iturup Island by a low isthmus only 30 m high. A somma volcano whose caldera rim is exposed only at about 900 m elevation on the SE side was constructed during the late Pleistocene or early Holocene, forming an island up to about 1.5 km high that was later connected to Iturup Island by erosional material. A fault with large displacement offsets the NW side of the somma of Atsonupuri (also known as Etorofu-Atosanupuri). The 2-km-wide caldera was subsequently largely overtopped by a central cone that forms the present 1206-m-high summit. Strombolian eruptions have dominated the history of this basaltic volcano; few lava flows are exposed. Only two historical eruptions are known at Atsonupuri, during 1812 and 1932.

Bogatyr Ridge
Pyroclastic cones
Lava dome
The Bogatyr Ridge on Iturup Island in the southern Kuriles consists of a cluster of small NE-SW-trending late-Pleistocene to Holocene cones and craters, along with the larger Stokap stratovolcano at the SW end of the ridge. The basaltic-andesite to andesitic Stokap volcano is capped by a complex of 8-10 cones and explosion craters, the largest of which contains a lake. The volcanic chain was constructed over a high Pleistocene base, whose glaciated surface is covered by lava flows from Stokap volcano that reach to both the Pacific Ocean and the Sea of Okhotsk. No historical eruptions are known from the volcanic chain.

Grozny Group
Complex volcanoes
The Grozny volcano group in central Iturup Island contains the complex volcanoes of Ivan Grozny and Tebenkov. The former has a 3-3.5 km diameter caldera that is open to the south, where the large, 1158-m-high andesitic Grozny extrusion dome (also known as Etorofu-Yake-yama) was emplaced. Several other lava domes of Holocene age were constructed to the NE; extrusion of these domes has constricted a former lake in the northern side of the caldera to an extremely sinuous shoreline. The forested andesitic Tebenkov volcano, also known as Odamoi-san, lies immediately to the NE of the Grozny dome complex. The large Machekh crater, which displays strong fumarolic activity, lies immediately south of Tebenkov. Historical eruptions, the first of which took place in 1968, have been restricted to Ivan Grozny.

Baransky
Lava dome
The Baransky volcanic complex along the Pacific coast in the central part of Iturup Island consists of an eroded Pleistocene volcano that is capped by a Holocene stratovolcano. A young summit lava dome is cut by a NW-trending chain of small explosion craters. A group of flank cones farther to the NW with a similar NW-SE orientation is partially surrounded by lava flows from the central crater of the andesitic-dacitic volcano. Lava flows from Baransky (also known as Sashiusu-dake) descended 4-5 km SE to reach the Pacific Ocean along a broad front. The only historical eruption occurred in 1951, when local inhabitants reported weak explosive activity at the summit. Strong solfataric activity continues from the summit and several flank craters, and the SW flank geothermal field contains hot springs and geysers. A small hydrothermal explosion took place in 1992 at an exploratory well in the SW-flank geothermal field.

Chirip
Stratovolcanoes
The Chirip Peninsula, jutting NW-ward into the Sea of Okhotsk from central Iturup Island, is constructed of twin overlapping Holocene stratovolcanoes. Chirip volcano on the north and Bogdan Khmelnitskii on the south overlie a preglacial volcano, rising above a 1100-m-high saddle to 1561 and 1587 m, respectively. Lava flows from both volcanoes are truncated by a large, 4-km-wide depression on the west side of the peninsula. Basaltic rocks dominate at both volcanoes over basaltic-andesite and andesitic products. Chirip volcano has a shallow summit crater, partially filled by a small lake, that has fed lava flows down all sides. Satellitic cones are located on the northern flank of Chirip. Lava flows from Bogdan Khmelnitskii (also known as Minami-Chirippu or South Chirippu) reach the coast on both the east and west sides. Only two 19th-century eruptions are known in historical time, the last occurring in 1860 from a vent SE of the summit of Bogdan Khmelnitskii.

Golets-Tornyi Group
The small pyroclastic cones of Golets and Tornyi, located SW of Medvezhii volcano at one of the narrowest parts of Iturup Island, formed during the late Pleistocene or early Holocene. A small lava flow from 417-m-high Tornyi cone occupies a broad glacial cirque. The 442-m-high andesitic-dacitic Golets cone, constructed above the eroded remnants of the Pleistocene Parusnaya Mountain volcano, produced lava flows that reached the coast.

Medvezhia
Somma volcano
Calderas
The Medvezhia volcanic complex occupies the NE end of Iturup Island. Two overlapping calderas, 14 x 18 and 10 x 12 km in diameter, were formed during the Pleistocene. The caldera floor contains several lava domes, cinder cones and associated lava fields, and a small lake. Four small closely spaced stratovolcanoes were constructed along an E-W line on the eastern side of the complex. The easternmost and highest, Medvezhii, lies outside the western caldera, along the Pacific coast. Srednii, Tukap, and Kudriavy volcanoes lie immediately to the west. Historically active Kudriavy (also known as Moyoro-dake) is younger than 2000 years; it and Tukap remain fumarolically active. The westernmost of the post-caldera cones, Menshoi Brat, is a large lava dome with flank scoria cones, one of which has produced a series of young lava flows up to 4.5 km long that reached Slavnoe Lake. Eruptions of Kudriavy have been documented since the 18th century, although lava flows from cinder cones on the flanks of Menshoi Brat were also probably erupted within the past few centuries.

Demon
Demon volcano occupies the extreme northern tip of the largest island in the Kuriles, Iturup. The 1205-m-high stratovolcano grew during the Holocene within a glacial trough 3 km east of the eroded Pleistocene Kamui volcano. The summit of Demon contains a 1.5-km-wide crater open to the east.
Smithsonian Volcano Information | Kamchatka Volcanic Eruption Response Team

Ivao Group
Urup Island
Cinder cones
The Ivao group of cones along the Krishtofovich Ridge of SW Urup Island contains several well-preserved cones of Holocene age. The first of a group of three young cones that formed along a NW-SE line is 1426-m-high Ivao cone, which marks the high point of Urup Island at the NW end of the chain. The SE-most cone bisects a glacial valley, forming Lake Ivao. The elongated central cone, Krutaya Mountain, is the youngest, and produced a viscous lava flow that traveled to the east.
Smithsonian Volcano Information | Kamchatka Volcanic Eruption Response Team

Rudakov
Urup Island
The small isolated cone of Rudakov occupies the Tokotan Isthmus on the Sea of Okhotsk coast of central Urup Island. The 542-m-high basaltic-andesite stratovolcano lies between Petr Shmidt ridge and Krishtofovich Ridge and is capped by a 700-m-wide, funnel-like crater containing a 300-m-wide lake. The age of Rudakov was considered to be late Pleistocene or early Holocene (Gorshkov, 1970).
Smithsonian Volcano Information | Kamchatka Volcanic Eruption Response Team

Tri Sestry
Urup Island
Lava dome
Tri Sestry, located on the shore of the Sea of Okhotsk in central Urup Island, is an eroded andesitic stratovolcano whose flanks are cut by deep ravines. A summit lava dome on Tri Sestry ("Three Sisters") was active during either the late Pleistocene or early Holocene (Gorshkov, 1970). Hot springs along the coast mark its latest activity.

Kolokol Group
Somma volcanoes
A group of Holocene volcanoes in central Urup Island is named after its most prominent volcano, Kolokol. Berg and Trezubetz volcanoes, flanking Kolokol on the NW, have breached summit calderas partially filled by lava domes. Trezubetz, whose name means "trident," has an eroded crater rim with three large peaks when seen at sea from the north. Kolokol volcano rises to 1328 m and is sometimes known as Urup-Fuji because of its symmetrical profile. The crater of Kolokol is not well preserved, but the volcano displays no evidence of glacial erosion. Several lava flows originate from Kolokol; one of these extends almost to the Sea of Okhotsk coast. A viscous lava flow armoring the SE flank is probably the most recent from Kolokol. Borzov volcano, the oldest of the group, lies to the SW of Kolokol. Eruptions of the Kolokol volcano group have been observed in historical time since the late-18th century. Berg volcano has been most active, but Trezubetz erupted in 1924.

Chirpoi
Kuril Islands (Russia)
Stratovolcanoes
Chirpoi, a small island lying between the larger islands of Simushir and Urup, contains a half dozen volcanic edifices constructed within an 8-9 km wide, partially submerged caldera. The southern rim of the caldera is exposed on nearby Brat Chirpoev Island. Two volcanoes on Chirpoi Island have been historically active. The symmetrical Cherny volcano, which forms the 691 m high point of the island, erupted twice during the 18th and 19th centuries. The youngest volcano, Snow, originated between 1770 and 1810. It is composed almost entirely of lava flows, many of which have reached the sea on the southern coast. No historical eruptions are known from 742-m-high Brat Chirpoev, but its youthful morphology suggests recent strombolian activity.

Unnamed
Kuril Islands (Russia)
Submarine volcano
Summit Elev: -502? m
Hydrophones detected signals in 1972 interpreted to be from a submarine eruption in the Kuriles, probably between Simushir and Urup Island (Smithsonian Institution Center for Short-Lived Phenomena). Three seamounts have been located between Urup and Simushir Islands, east and NE of Chirpoi Island (Tsvetkov 1991, pers. comm.), but the hydrophone signal is not accurately enough located to determine its precise origin. The location given here is arbitrarily that of the seamount most centrally located between Urup and Simushir Islands.
About Volcano Data |

Milne
Simushir Island
Somma volcano
Milne volcano, the southernmost on Simushir Island in the central Kuriles, lies immediately SE of the somma of Goriaschaia volcano. The outer flanks of the steep-sided 1540-m-high volcano are dissected by deep gullies. A 3-km-wide caldera breached widely to the south was formed during the Pleistocene and became a center of glaciation. A small central cone capped by an andesitic lava dome was constructed within the caldera during postglacial time and forms the highest point on Simushir Island. Lava flows from the central cone descend 4-5 km to the sea.

Goriaschaia Sopka
Simushir Island
Goriaschaia Sopka is a young, historically active lava dome at the SW end of Simushir Island in the central Kuriles. The dome is located within a large horseshoe-shaped crater cutting the NW flank of the older Igla Mountain somma volcano. A low saddle separates Igla Mountain from Milne, a large stratovolcano immediately to the SE. Numerous fresh lava flows with prominent marginal levees extend from the Goriaschaia Sopka dome; some reached the sea, where they created an irregular shoreline. The andesitic dome may have formed as recently as the late-19th century. Historical activity, consisting dominantly of mild-to-moderate explosive eruptions, has occurred since 1842.

Zavaritzki Caldera
Simushir Island
Scoria cone
Zavaritzki volcano in central Simushir Island contains three nested calderas of 10-, 8-, and 3-km diameter. The steep-walled youngest caldera was formed during the Holocene and contains a lake whose surface is about 40 m elevation and whose bottom lies about 30 m below sea level. Several young cones and lava domes are located near the margins of Biryuzovoe caldera lake. Lacustrine sediments overlying pumice deposits indicate that an earlier caldera lake lay at 200 m above sea level, well above the present lake surface. Two eruptions have occurred at Zavaritzki during the 20th century. A lava dome that was emplaced sometime between 1916 and 1931 forms a small island in the northern part of the caldera lake. In 1957, a new 350-m-wide, 40-m-high dome was emplaced following explosive eruptions, decreasing the size of the caldera lake.

Prevo Peak
Symmetrical Prevo Peak, also known as Simushiru-Fuji for its resemblance to Japan's noted volcano, is capped by a 450 x 600 m wide summit crater. A nested inner cone whose rim approaches the height of portions of the outer cone is itself cut by a deep, 350-m-wide crater with a small lake on its floor. Young-looking lava flows reach both coasts of central Simushir Island, and those on the south flank (Pacific Ocean side) have a particularly youthful appearance. Two small pyroclastic cones on the western flank have produced lava flows that reach to or near the Sea of Okhotsk. Only two eruptions are known from Prevo Peak in historical time. The largest of these, during the 1760s, produced pyroclastic flows that destroyed all vegetation at the foot of the volcano. Weak explosive activity occurred during the most recent eruption, which took place during the first half of the 19th century.

Urataman
Somma volcano
Cinder cones
The northernmost of six Quaternary volcanoes on Simushir Island, Urataman consists of an impressive 7.5-km-wide Pleistocene caldera that forms the NE tip of the island. Caldera walls rise 450 m above a 250-m-deep caldera bay. A narrow gap in the northern caldera rim provides sea-water access into the half-moon-shaped Brouton Bay, which fills the NW half of the caldera. A central cone, andesitic Urataman volcano, has grown to a height of 678 m during the Holocene in the SE part of the caldera. Two cinder cones are located along the northern flank of Urataman, and a lava dome was formed on its NW flank along Brouton Bay. No historical eruptions are known from Urataman.

Ketoi
Kuril Islands (Russia)
The circular, 10-km-wide Ketoi island, which rises across the 19-km-wide Diana Strait from Simushir Island, hosts of one of the most complex volcanic structures of the Kuril Islands. The rim of a 5-km-wide Pleistocene caldera is exposed only on the NE side. A younger 1172-m-high stratovolcano forming the NW part of the island is cut by a horst-and-graben structure containing two solfatara fields. A 1.5-km-wide freshwater lake fills an explosion crater in the center of the island. Pallas Peak, a large andesitic cone in the NE part of the caldera, is truncated by a 550-m-wide crater containing a brilliantly colored turquoise crater lake. Lava flows from Pallas Peak overtop the caldera rim and descend nearly 5 km to the SE coast. The first historical eruption of Pallas Peak, during 1843-46, was its largest.

Ushishur
The subaerial portion of Ushishur volcano in the central Kuriles is exposed in two small islands, the southern containing the summit caldera and the northern a portion of the volcano's flanks. A small 1.6-km-wide caldera that formed about 9400 years ago is narrowly breached on the south, allowing sea water to fill the caldera. Two andesitic lava domes occupy part of the caldera bay; two other older domes are joined by a sand bar to the SE caldera wall. The two younger domes, erupted sometime after the 1769 visit of Captain Snow, form islands in the bay. A cluster of strong fumaroles and hot springs along the SE caldera shoreline was a sacred place to 18th- and 19th-century Kurile Ainu peoples, and vigorous submarine hydrothermal activity has modified the geochemistry of sea water within the caldera bay. Aside from growth of the two younger lava domes, only minor phreatic eruptions have occurred at Ushishur during historical time.

Srednii
Northwest of Ushishur Island
Submarine volcano
Remnants of the Srednii submarine volcano form a hazardous obstruction in the strait between Rasshua and Ushishur Islands. Flat-topped Khitraya Rock may be a young (Holocene) extrusion dome, and adjoining rocks may be the rim of an old caldera (Gorshkov 1970). Sapper (1917), Neumann Van Padang (1938), and Gushchenko (1979) reported a submarine eruption between Rasshua and Ushishur Islands on July 12, possibly in 1880 (the year is uncertain).
About Volcano Data |

Rasshua
The elongated 6 x 13 km island of Rasshua in the central Kuriles contains three overlapping central cones within a 6 km caldera whose eastern margin is beyond the shoreline. An eroded central cone was constructed during the late Pleistocene, along with an isolated cone near the NW coast. Two Holocene cones were built within the crater of the central cone. The westernmost forms the 956 m high point of the island and is the source of lava flows that flooded the crater floor and descended to the coast. The easternmost cone, active during historical time, is truncated by a 500-m-wide crater that is breached to the SE. This crater may have formed during a violent eruption in 1846. The only other known historical eruption produced weak explosions in 1957. Fumarolic activity continues in the eastern crater and in the saddle between the two summit cones.

Unnamed
East of Matua Island
Submarine volcano
Summit Elev: -150 m
The Catalog of Active Volcanoes of the World reported an eruption in 1924 from a submarine volcano east of Matua Island in the central Kuriles. Gorshkov (1970) noted confusion in the literature about the location of this eruption and placed it, based on the original description, north of Toporkovyi islet (Banzio-Iwa). A small ridge extending northward from Matua and Toporkovyi reaches to a shallow depth at this point.
About Volcano Data |

Sarychev Peak
Matua Island
Sarychev Peak, one of the most active volcanoes of the Kuril Islands, occupies the NW end of Matua Island in the central Kuriles. The andesitic central cone was constructed within a 3-3.5 km wide caldera, whose rim is exposed only on the SW side. A dramatic 250-m-wide, very steep-walled crater with a jagged rim caps the volcano. The substantially higher SE rim forms the 1496 m high point of the island. Fresh-looking lava flows descend all sides of Sarychev Peak and often form capes along the coast. Much of the lower-angle outer flanks of the volcano are overlain by pyroclastic-flow deposits. Eruptions have been recorded since the 1760's and include both quiet lava effusion and violent explosions. The largest historical eruption of Sarychev Peak in 1946 produced pyroclastic flows that reached the sea.

Raikoke
A low, 551-m-high truncated volcano forms the small barren Raikoke Island, which lies 16 km across the Golovnin Strait from Matua Island in the central Kuriles. The oval-shaped basaltic island is only 2 x 2.5 km wide and rises above a submarine terrace with a depth of 130 m. The steep-walled crater, highest on the SE side, is 700 m wide and 200 m deep. Lava flows mantle the eastern side of the island. A catastrophic eruption of Raikoke in 1778 during which the upper third of the island was said to have been destroyed prompted the first volcanological investigation in the Kuril Islands two years later. Reports of eruptions in 1777 and 1780 are erroneous (Gorshkov, 1970). Another powerful eruption in 1924 greatly deepened the crater and changed the outline of the island.

Chirinkotan
Pyroclastic cone
The small, mostly unvegetated 3-km-wide island of Chirinkotan occupies the far end of an E-W-trending volcanic chain that extends nearly 50 km west of the central part of the main Kuril Islands arc. Chirinkotan is the emergent summit of a volcano that rises 3000 m from the floor of the Kuril Basin. A small 1-km-wide caldera about 300-400 m deep is open to the SE. Lava flows from a cone within the breached crater reached the north shore of the island. Historical eruptions have been recorded at Chirinkotan since the 18th century. Fresh lava flows also descended the SE flank of Chirinkotan during an eruption in the 1880s that was observed by the English fur trader Captain Snow.

Ekarma
The small 5 x 7.5 km island of Ekarma lies 8.5 km north of Shiashkotan Island along an E-W-trending volcanic chain extending westward from the central part of the main Kuril Island arc. Ekarma is composed of two overlapping basaltic-andesite to andesitic volcanoes, the western of which has been historically active. Lava flows radiate 3 km in all directions from the summit of the younger cone to the sea, forming a lobate shoreline. A lava dome that was emplaced during the first historical eruption, in 1776-79, forms the peaked, 1170-m-high summit of the island. The only other historical eruption produced minor explosions in 1980.

Kuntomintar
Shiashkotan Island
Hydrothermal field
Kuntomintar is a Pleistocene andesitic stratovolcano that occupies the southern end of Shiashkotan Island in the central Kuriles. A central cone fills a 4-4.5 km caldera, whose rim is visible on the NE side. A second caldera on the west side is breached to the west. An Ainu village that reportedly was destroyed by an eruption in 1872 was later found to be located near Sinarka volcano (Gorshkov, 1970). The only known postglacial activity of Kuntomintar is continuous solfataric activity that originates near the east wall of the inner caldera and a nearby hot sulfur spring.
Smithsonian Volcano Information

Sinarka
Shiashkotan Island
Sinarka volcano, occupying the northern end of Shiashkotan Island in the central Kuriles, has a complex structure. A small, 2-km-wide depression open to the NW has been largely filled and overtopped by an andesitic postglacial central cone that itself contains a lava dome that forms the 934 m high point of the island. Another lava dome, Zheltokamennaya Mountain, lies 1.5 km to the SW along the buried SW rim of the caldera, and a smaller dome lies along the northern caldera rim. Historical eruptions have occurred at Sinarka during the 17th and 18th centuries. The last and largest of these, during 1872-78, was once thought to originate from Kuntomintar volcano at the southern end of the island, but is now attributed to Sinarka volcano (Gorshkov, 1970).

Kharimkotan
The 8 x 12 km island of Kharimkotan (also spelled Harimkotan) in the northern Kuriles consists of a stratovolcano cut by two breached depressions on the east and NW sides. These horseshoe-shaped craters were formed by slope failure, which produced debris-avalanche deposits that form large broad peninsulas on the east and NW coasts. Evidence of additional slope failures followed by plinian eruptions are found in sea cliffs of the island. Historical explosive eruptions have occurred since the early 18th century. A central cone, Severgin, was largely destroyed during the 1933 eruption, one of the largest in the Kuril Islands during historical time. Impact of a debris avalanche into the sea from the collapse of Severgin produced a tsunami that swept the island's coast and reached Onekotan and Paramushir Islands, killing two persons. A large lava dome emplaced during the 1933 eruption now fills the head of the eastern crater.

Tao-Rusyr Caldera
Onekotan Island
The 7.5-km-wide Tao-Rusyr caldera on southern Onekotan Island is one of the most impressive volcanoes of the Kuril Islands. The basaltic-to-andesitic caldera is filled by the deep-blue 7-km-wide Kal'tsevoe lake, whose surface is 400 m above sea level. The caldera was formed about 7500 years ago during one of the largest Holocene eruptions in the Kuril Islands. A large symmetrical post-caldera cone, 1325-m-high andesitic Krenitzyn Peak, forms a 4-km wide island that towers high above the caldera rim and fills the NW portion of the caldera lake. A 350-m-wide, 100-m-deep crater truncates the peak and a large lateral crater is located on the upper NE side. The only historical eruption of Krenitzyn Peak, in 1952, formed a small, mostly lacustral lava dome in an explosion crater along the east shore of the island.

Nemo Peak
Onekotan Island
Nemo Peak volcano at the northern end of Onekotan Island in the northern Kuriles is truncated by two nested calderas of preglacial age, the largest of which is 10 km in diameter and extends to the northern coast. A third 5-km-wide caldera formed about 25,000 years ago by collapse of an interglacial cone that was constructed over the glaciated surfaces of the earlier calderas. The 1018-m-high central cone of Nemo Peak is composed of two coalescing andesitic cones that were constructed at the SW side of the youngest caldera and formed in four stages beginning in the early Holocene about 9500 years ago. Construction of the central cone has left the crescent-shaped Chernoe Lake at the NE end of the youngest caldera; lava flows from Nemo Peak form the broad SW shoreline of the lake. The final activity built a lava dome that completely overtops a 350-m-wide crater and has a 150-m-wide crater at its summit. Historical eruptions of Nemo Peak date back to the early-18th century.

Shirinki
The small, 3-km-wide island of Shirinki, part of a chain of volcanoes west of the main Kuril Island arc, is located 15 km west of Fuss Peak on Paramushir Island. The truncated andesitic cone is of Holocene age and rises to a height of 761 m. The walls of the 750-m-wide breached summit crater extend to the southern coast. Two lava domes were constructed near the headwall of the breached crater. No historical eruptions are known from Shirinki, but the summit domes are very young and possibly formed in historical time (Gorshkov, 1970). The remnants of an older volcano occupy the eastern side of the island, much of which is covered by pumiceous pyroclastic-fall deposits.

Fuss Peak
Paramushir Island
Fuss Peak in the northern Kuriles forms a peninsula that lies across a low isthmus on the SW coast of Paramushir Island. The volcano rises 2800 m from the floor of the Sea of Okhotsk to a height of 1772 m. This isolated symmetrical andesitic stratovolcano has a 700-m-wide, steep-walled crater that is 300 m deep. A deep notch cuts the NW rim of the crater to the level of the crater floor, at the head of a canyon that reaches the coast. Well-preserved lava flows occupy the middle and lower flanks, particularly on the east and SE sides. Only one unambiguous historical eruption, in 1854, is known from Fuss Peak. Reports of eruptions in 1737, 1793, 1857, and 1859 are false (Gorshkov, 1970). Murayama (1987) also listed an eruption in 1742 (only earthquakes and a tsunami are cited by Sapper, 1917) and "smoke" emission in 1933.

Karpinsky Group
Paramushir Island
Cones
Maar
The Karpinsky group on southern Paramushir Island consists of three Holocene andesitic volcanic centers at the southern end of the Karpinsky Ridge. A postulated caldera is thought to have been primarily excavated by glaciers (Gorshkov, 1970). The NE cone has a crater breached to the NW that contains a small horseshoe-shaped cone and a vigorous fumarole along the NE crater wall. A lava flow originating from the cone traveled 7 km to the SE. The 1345-m southern cone forms the high point of the Karpinsky massif and fed lava flows to the SE and west. The NW cone displays hot springs and sulfur cones containing liquid sulfur that is occasionally ejected outward. A minor ash ejection following an earthquake in 1952 marked the only historical eruption of the Karpinsky group.

Lomonosov Group
Paramushir Island
Cinder cones
The Lomonosov volcano group, south of Tatarinov volcano on southern Paramushir Island, consists of four cinder cones and a lava dome of Holocene age that were constructed along a N-S line. The northernmost cone was purely explosive; the second cone, Mount Boryask, produced a 3.5-km-long lava flow that traveled to the east. The third cone was the source of a lava flow that traveled 5.5 km to the east and NE. The 1681-m high point of the complex is Lomonosov proper, a lava dome located near the southern end of the volcano group. It fed a 7-km-long lava flow extending westward nearly to the shore of the Sea of Okhotsk. The southernmost vent was the source of a lava flow that traveled 4 km initially SE and then east.

Chikurachki
Stratovolcanoes
Chikurachki, the highest volcano on Paramushir Island in the northern Kuriles, is actually a relatively small cone constructed on a high Pleistocene volcanic edifice. Oxidized basaltic-to-andesitic scoria deposits covering the upper part of the young cone give it a distinctive red color. Frequent basaltic plinian eruptions have occurred from Chikurachki during the Holocene. Lava flows from 1816-m-high Chikurachki reached the sea and form capes on the NW coast; several young lava flows also emerge from beneath the scoria blanket on the eastern flank. The Tatarinov group of six volcanic centers is located immediately to the south of Chikurachki. In contrast to the frequently active Chikurachki, the Tatarinov volcanoes are extensively modified by erosion and have a more complex structure. Tephrochronology gives evidence of only one eruption in historical time from Tatarinov, although its southern cone contains a sulfur-encrusted crater with fumaroles that were active along the margin of a crater lake until 1959.

Vernadskii Ridge
The Vernadskii and Bogdanovich volcano groups on northern Paramushir island in the northern Kuriles comprise the two southernmost of three volcano groups on the Vernadskii Ridge, immediately south of the historically active Ebeko volcano group. The Vernadskii group, at the southern end of the volcanic complex, contains three centers, one of which is topped by a lava dome. The Bogdanovich group, 4-5 km to the north, is composed of five eruptive centers that have produced small cones and lava flows. Gorshkov (1970) considered that eruptive activity at both the Vernadskii and Bogdanovich volcano groups continued into the Holocene.

Ebeko
The flat-topped summit of the central cone of Ebeko volcano, one of the most active in the Kuril Islands, occupies the northern end of Paramushir Island. Three summit craters located along a SSW-NNE line form Ebeko volcano proper, at the northern end of a complex of five volcanic cones. Blocky lava flows extend west from Ebeko and SE from the neighboring Nezametnyi cone. The eastern part of the southern crater of Ebeko contains strong solfataras and a large boiling spring. The central crater of Ebeko is filled by a lake about 20 m deep whose shores are lined with steaming solfataras; the northern crater lies across a narrow, low barrier from the central crater and contains a small, cold crescentic lake. Historical activity, recorded since the late-18th century, has been restricted to small-to-moderate explosive eruptions from the summit craters. Intense fumarolic activity occurs in the summit craters of Ebeko, on the outer flanks of the cone, and in lateral explosion craters.

Alaid
The highest and northernmost volcano of the Kuril Islands, 2339-m-high Alaid is a symmetrical stratovolcano when viewed from the north, but has a 1.5-km-wide summit crater that is breached widely to the south. Alaid is the northernmost of a chain of volcanoes constructed west of the main Kuril archipelago and rises 3000 m from the floor of the Sea of Okhotsk. Numerous pyroclastic cones dot the lower flanks of basaltic to basaltic-andesite Alaid volcano, particularly on the NW and SE sides, including an offshore cone formed during the 1933-34 eruption. Strong explosive eruptions have occurred from the summit crater beginning in the 18th century. Reports of eruptions in 1770, 1789, 1821, 1829, 1843, 1848, and 1858 were considered incorrect by Gorshkov (1970). Explosive eruptions at Alaid in 1790 and 1981 were among the largest in the Kuril Islands during historical time.

Japan, Taiwan, Marianas

Taiwan

Unnamed
East of Taiwan
A submarine eruption observed by the U.S. Navy boat "Southampton" took place on October 29, 1853 in the Philippine Sea offshore from the city of Hualien about 18 km from the eastern coast of Taiwan. Several days later another ship, the "Macedonian," passed the same location and reported white ash covering its curtains.
Smithsonian Volcano Information

Kueishantao
East of Taiwan
Kueishantao Island, whose summit is 401 m above sea level, is the southernmost of five small volcanic islands off the NE coast of Taiwan. Kueishantao, also known as Guieshan Island, consists of andesitic lava flows and volcaniclastic material. Kueishantao is the southwesternmost volcano along the axis of the Okinawa Trough back-arc basin that extends to the NE from Taiwan to Unzen volcano in Kyushu. The SW tip of the Okinawa Trough extends past Kueishantao onto the Ilao Plain on the island of Taiwan. The island is known as "Turtle Mountain Island" due to its profile as seen from some points on the coast of Taiwan. Historical accounts during the time of King Qianlong of the Qing Dynasty (1775-1795 AD) noted the Guieshan mountain split open with a blood-red lava flow. Kueishantao displays vigorous active submarine fumaroles and solfataras that discolor seawater over wide areas.
Smithsonian Volcano Information

Tatun Group
Taiwan
The Tatun (Datun) volcano group is a series of andesitic stratovolcanoes and lava domes in the northernmost part of Taiwan. About 20 volcanoes, the southernmost of which is only 15 km north of the capital city of Taipei, are included in the Tatun group. The highest and youngest volcano is 1120-m-high Chisingshan. The latest dated eruptions in the group took place over a roughly 3000-year period beginning about 20,000 years ago. Hot springs, fumaroles, and solfataras are found over wide areas, and extensive geothermal exploration has occurred at the Daiton geothermal area.

Pengchiahsu
North of Taiwan
Pengchiahsu is one of five small Pleistocene volcanic islands NE of Taiwan. The summit of andesitic Pengchiahsu island (also known as Agincourt) reaches only 129 m above sea level. The age of volcanism is considered to be Pleistocene, but Pengchiahsu displays fumarolic activity (Volcanological Society of Japan, 1971).

Ryukyu Islands & Kyushu

Iriomote-jima
Ryukyu Islands (Japan)
Summit Elev: -200 m
The southernmost Ryukyu Islands volcano is a shallow submarine volcano north of Iriomote-jima island. The submarine volcano is located 25 km NNE of the NE tip of Iriomote-jima and 35 km WSW of the northern tip of the island of Ishigaki-shima in an area with an estimated depth of 200-300 m. A major submarine eruption took place at this volcano on October 31, 1924. It produced rhyolitic pumice rafts with an estimated volume of about 1 cu km that were carried by currents along both coasts of Japan as far north as Hokkaido. The largest pumice blocks exceeded 1 x 2 m in size, and the volume of ejecta places this poorly known eruption among the largest in historical time in Japan.
Smithsonian Volcano Information | Japan Meteorological Agency | Geological Survey of Japan

Iwo-Tori-shima
Ryukyu Islands (Japan)
Complex volcano
The 1 x 2.7 km island of Iwo-Tori-shima (also known as Okinawa-Tori-shima), located north of the largest island of the Ryukyus, Okinawa, is composed of two andesitic volcanoes. Tori-shima (Bird Island) is a common name for offshore islands in Japan. Kusuku lava dome occupies the center of the inner of two sommas on the SE-most volcano. The summit crater of the NW-most volcano, Iwo-dake, contains a small lake, solfataras, and sulfur deposits that were mined in the past. Historical eruptions dating back to 1664 have consisted of mild-to-moderate explosive activity.
Smithsonian Volcano Information | Japan Meteorological Agency | Geological Survey of Japan

Yokoate-jima
Ryukyu Islands (Japan)
Yokoate-jima is a small, 3.5-km-long, dumbbell-shaped island NW of Amami Oshima Island at the SW end of the Tokara island chain. Two peaks, Higashimine on the east and Nishimine on the west, form the andesitic island. The 495-m-high Higashimine, the high point of the island, has a steep-walled, well-preserved summit crater. An arcuate ridge east of Yokoate-jima appears to be part of 7 x 10 km wide submarine caldera, with Yokoate-jima and Kannone-jima (NNE of Yokoate-jima) being post-caldera cones (Nakano et al., 2001-). Yokoate-sho (Yokoate Reef) and Kannone Kaikyu (Kannone Knoll) lie to NNW and NE of Yokoate-jima, respectively. Historical documents at the end of the Edo Period mention ash plumes from Yokoate-jima.
Smithsonian Volcano Information | Japan Meteorological Agency | Geological Survey of Japan

Akuseki-jima
Akuseki-jima is a small, 584-m-high stratovolcano in the southern Ryukyu Islands that rises about 800 above the sea floor. Most of the island is surrounded by steep cliffs, and beaches are found only on the SW and SE sides. The andesitic-dacitic volcano consists of two older somma volcanoes, Biro-yama and Naka-dake. Mi-take lava dome forms the high point of the small 2.5 x 3.2 km wide island. The dacitic Omune lava flow on the NE flank was Potassium-Argon dated at <80,000 yrs Before Present, and its youthful morphology and lack of overlying tephra layers suggests it could be as young as the Holocene (Furuyama et al., 2002). The lava flow, the youngest product of Akuseki-jima volcano, forms a low-angle plateau overlying cliffs forming the northern coast.

Suwanose-jima
Fissure vents
The 8-km-long, spindle-shaped island of Suwanose-jima in the northern Ryukyu Islands consists of an andesitic stratovolcano with two historically active summit craters. Only about 50 persons live on the sparsely populated island. The summit of the volcano is truncated by a large breached crater extending to the sea on the east flank that was formed by edifice collapse. Suwanose-jima, one of Japan's most frequently active volcanoes, was in a state of intermittent strombolian activity from On-take (Otake), the NE summit crater, that began in 1949 and lasted until 1996, after which periods of inactivity lengthened. The largest historical eruption took place in 1813-14, when thick scoria deposits blanketed residential areas, and the SW crater produced two lava flows that reached the western coast. At the end of the eruption the summit of On-take collapsed forming a large debris avalanche and creating the horseshoe-shaped Sakuchi caldera, which extends to the eastern coast. The island remained uninhabited for about 70 years after the 1813-1814 eruption. Lava flows reached the eastern coast of the island in 1884.

Nakano-shima
The 9 x 5 km island of Nakano-shima is surrounded by coral reefs. A flat plateau separates an older dissected volcano on the south from the active andesitic cone of On-take, which forms the northern half of the island. On-take contains a summit crater that is filled with water during the rainy season. Sulfur deposits were mined at a SE-flank solfatara until 1944. Only very minor activity has been reported in historical time. A small mud eruption took place in 1914 at the summit crater, and "smoking" increased in 1949.

Kogaja-jima
Kogaja-jima is a small volcanic island located NW of Nakano-shima. The andesitic lava domes were considered to be of late-Pleistocene to Holocene age (Nakano et al., 2001-). Kogaja-jima (Little Gaja Island) lies ESE of the larger Gaja-jima stratovolcano. The 301-m-high Kogaja-jima volcano displays minor fumarolic activity exposed in coastal cliffs.

Gaja-jima
Gaja-jima volcano lies east of the main arc Ryukyu arc, WNW of Nakano-shima. The andesitic stratovolcano reaches 497 m above sea level. The age of the volcano is not known precisely and Gaja-jima was considered to be of late-Pleistocene to Holocene age (Nakano et al., 2001-). Kogaja-jima (Little Gaja Island) lies ESE of Gaja-jima.

Kuchino-shima
Kuchino-shima, lying in the northern Ryukyu Islands between the volcanic islands of Nakano-shima and Kuchinoerabu-jima, consists of two andesitic stratovolcanoes and a NW-SE-trending chain of lava domes. Two small villages, Nishinohama and Kuchino-shima, lie at the northern end of the mostly uninhabited island. The compound 628-m-high Mae-dake lava dome, forming the highest point on the 3 x 7 km wide island, was constructed east of the summit of 501-m-high Yoko-dake stratovolcano. The last magmatic eruption at Kuchino-shima took place about 1200-1300 years ago.

Kuchinoerabu-jima
A group of young stratovolcanoes forms the eastern end of the irregularly shaped island of Kuchinoerabu-jima in the northern Ryukyus, 15 km west of Yaku-shima. Furu-take, Shin-take, and Noike were erupted from south to north, respectively, to form a composite cone that is parallel to the trend of the Ryukyu Islands. The highest peak, Furu-take, reaches only 657 m above sea level. The youngest cone, 640-m-high Shin-take, was formed after the NW side of Furu-take was breached by an explosion. All historical eruptions have occurred from Shin-take, although a lava flow from the south flank of Furu-take that reached the coast has a very fresh morphology. Frequent explosive eruptions have taken place from Shin-take since 1840; the largest of these was in December 1933. Several villages on the 4 x 12 km island are located within a few km of the active crater of Shin-take and have suffered damage from eruptions.

Kikai
Kikai is a mostly submerged, 19-km-wide caldera near the northern end of the Ryukyu Islands south of Kyushu. Kikai was the source of one of the world's largest Holocene eruptions about 6300 years ago. Rhyolitic pyroclastic flows traveled across the sea for a total distance of 100 km to southern Kyushu, and ashfall reached the northernmost Japanese island of Hokkaido. The eruption devastated southern and central Kyushu, which remained uninhabited for several centuries. Post-caldera eruptions formed Iwo-dake lava dome and Inamura-dake scoria cone, as well as submarine lava domes. Historical eruptions have occurred in the 20th century at or near Tokara-Iwo-Jima (also known as Satsuma-Iwo-jima), a small 3 x 6 km island forming part of the NW caldera rim. Showa-Iwo-jima lava dome (also known as Iwo-jima-Shinto), a small island 2 km east of Tokara-Iwo-jima, was formed during submarine eruptions in 1934 and 1935. Mild-to-moderate explosive eruptions have occurred during the past few decades from Iwo-dake, a rhyolitic lava dome at the eastern end of Tokara-Iwo-jima.

Ibusuki Volcanic Field
Kyushu
Calderas
Ibusuki volcanic field at the southern tip of Kyushu consists of numerous central cones and maars, the 4.5-km-wide Ikeda-ko caldera, and Kaimon-dake stratovolcano. The symmetrical, 922-m-high andesitic Kaimon-dake is the most prominent feature of the volcanic field and is capped by a lava dome. The large Pleistocene Ata caldera, once thought to partially underlie the Ibusuki volcanic field, is now considered to be located farther to the east beneath Kagoshima Bay. Ibusuki Volcanic Field has been very active during the Holocene, forming the Ikeda-ko caldera about 4600 years ago, numerous maars and lava domes, and, during the last 4000 years, Kaimon-dake. After about 2650 years ago, all eruptive activity has been restricted to Kaimon-dake. Its last eruption took place in the 9th century.

Sakura-jima
Kyushu
Sakura-jima, one of Japan's most active volcanoes, is a post-caldera cone of the Aira caldera at the northern half of Kagoshima Bay. Eruption of the voluminous Ito pyroclastic flow accompanied formation of the 17 x 23 km wide Aira caldera about 22,000 years ago. The smaller Wakamiko caldera was formed during the early Holocene in the NE corner of the Aira caldera, along with several post-caldera cones. The construction of Sakura-jima began about 13,000 years ago on the southern rim of Aira caldera and built an island that was finally joined to the Osumi Peninsula during the major explosive and effusive eruption of 1914. Activity at the Kita-dake summit cone ended about 4850 years ago, after which eruptions took place at Minami-dake. Frequent historical eruptions, recorded since the 8th century, have deposited ash on Kagoshima, one of Kyushu's largest cities, located across Kagoshima Bay only 8 km from the summit. The largest historical eruption took place during 1471-76.
Smithsonian Volcano Information | Sakurajima Volcano Observatory | Geological Survey of Japan

Sumiyoshi-ike
Kyushu
Maars
Sumiyoshi-ike and Yonemaru are two basaltic maars formed in coastal lowland deposits north of the Aira caldera. The eruptions occurred during a period of rising sea level at the beginning of the Holocene. The 500-m-wide Sumiyoshi-ike maar was created about 7000 years ago. The larger, 1.2-km-wide Yonemaru maar erupted about 2 km west of Sumiyoshi-ike about 6500 years ago and produced pyroclastic surges that traveled 4 km from the vent.

Kirishima
Shield volcano
Kirishima is a large group of more than 20 Quaternary volcanoes located north of Kagoshima Bay. The late-Pleistocene to Holocene dominantly andesitic volcano group consists of stratovolcanoes, pyroclastic cones, maars, and underlying shield volcanoes located over an area of 20 x 30 km. The larger stratovolcanoes are scattered throughout the field, with the centrally located, 1700-m-high Karakuni-dake being the highest. Onami-ike and Mi-ike, the two largest maars, are located SW of Karakuni-dake and at its far eastern end, respectively. Holocene eruptions have been concentrated along an E-W line of vents from Mi-ike to Ohachi, and at Shinmoe-dake to the NE. Frequent small-to-moderate explosive eruptions have been recorded since the 8th century.
Smithsonian Volcano Information | Kirishima Volcano Observatory | Geological Survey of Japan

Fukue-jima
Shield volcanoes
A group of small olivine basaltic shield volcanoes and cinder cones lies at the eastern end of Fukue-jima in the Goto Islands off the western coast of Kyushu. Activity at the Fukue volcano group began about 900,000 years ago, and the latest activity took place about 2000-3000 years ago (Nakano et al., 2001-). The volcano group is one of the active volcanoes monitored by the Japan Meteorological Agency. The volcanic field, whose high point (On-dake cinder cone) is only 317 m above sea level, forms peninsulas at the eastern and SE tips of Fukue Island as well as several smaller islands SE of Fukue.

Unzen
Complex volcano
The massive Unzen volcanic complex comprises much of the Shimabara Peninsula east of the city of Nagasaki. A 30-40-km-long, E-W-trending graben extends across the peninsula. Three large stratovolcanoes with complex structures, Kinugasa on the north, Fugen-dake at the east-center, and Kusenbu on the south, form topographic highs on the broad peninsula. Fugen-dake and Mayu-yama volcanoes in the east-central portion of the andesitic-to-dacitic Unzen volcanic complex have been active during the Holocene. The Mayu-yama lava dome complex, located along the eastern coast west of Shimabara City, formed about 4000 years ago and was the source of a devastating 1792 AD debris avalanche and tsunami. Historical eruptive activity has been restricted to the summit and flanks of Fugen-dake. The latest activity during 1990-95 formed a lava dome at the summit, accompanied by pyroclastic flows that caused fatalities and damaged populated areas near Shimabara City.
Smithsonian Volcano Information | Shimabara Earthquake and Volcano Observatory | Geological Survey of Japan

Aso
The 24-km-wide Aso caldera was formed during four major explosive eruptions from 300,000 to 90,000 years ago. These produced voluminous pyroclastic flows that covered much of Kyushu. The last of these, the Aso-4 eruption, produced more than 600 cu km of airfall tephra and pyroclastic-flow deposits. A group of 17 central cones was constructed in the middle of the caldera, one of which, Naka-dake, is one of Japan's most active volcanoes. It was the location of Japan's first documented historical eruption in 553 AD. The Naka-dake complex has remained active throughout the Holocene. Several other cones have been active during the Holocene, including the Kometsuka scoria cone as recently as about 210 AD. Historical eruptions have largely consisted of basaltic to basaltic-andesite ash emission with periodic strombolian and phreatomagmatic activity. The summit crater of Naka-dake is accessible by toll road and cable car, and is one of Kyushu's most popular tourist destinations.
Smithsonian Volcano Information | Aso Volcanological Laboratory | Geological Survey of Japan

Kuju
Kuju volcano is a complex of stratovolcanoes and lava domes lying NE of Aso caldera in north-central Kyushu. The Kuju volcano group consists of 16 andesitic lava domes, five andesitic stratovolcanoes, and one basaltic cone. Activity at the Kuju group dates back to about 150,000 years. Six major andesitic-to-dacitic tephra deposits, many associated with the growth of lava domes, have been recorded during the Holocene. Eruptive activity has migrated systematically eastward during the past 5000 years. The latest magmatic activity occurred about 1600 years ago, when Kuro-dake lava dome at the eastern end of the complex was formed. The first reports of historical eruptions were in the 17th and 18th centuries, when phreatic or hydrothermal activity occurred. Many hot springs and hydrothermal fields are located at the Kuju complex. A fumarole on Hosho lava dome was the site of a sulfur mine for at least 500 years. Two geothermal power plants are in operation at Kuju.

Tsurumi
The Tsurumi lava dome complex rises above the noted hot spring resort city of Beppu on Japan's Inland Sea. Two large lava domes, Tsurumi and Yufu, are located at the east and west sides of the complex, respectively. Three smaller lava domes are located on the north flank of the Tsurumi dome. The latest activity at both the andesitic-to-dacitic Tsurumi and Yufu groups postdates the 6300-years-old Akahoya ash from Kikai volcano. Pyroclastic flows dominated during older eruptions, whereas lava domes and lava flows are most common in more recent eruptions. An eruption about 2200 years ago from Yufu-dake volcano began with collapse of the northern flank that produced a debris avalanche and was followed by lava dome growth and associated pyroclastic flows. Only a single eruption, from Tsurumi in 867 AD, is known in historical time. The colorful hot spring pools and mudpots of Beppu along the coast form one of Japan's most noted thermal areas.

Honshu

Abu
Honshu
Shield volcanoes
The Abu volcano group, located along the Japan Sea coast near the SW end of Honshu, consists of basaltic-to-dacitic lava flows, small shield volcanoes (some of which have associated cinder cones) and lava domes. More than 40 monogenetic volcanoes are located in area of 400 sq km. Irao-yama at 641 m forms the high point of this group of small volcanic edifices, some of which form offshore islands. Volcanism here is considered to be related to subduction of the Philippine Sea Plate. An earlier phase of activity at the dominantly Pleistocene Abu volcano group during the late-Pliocene to early Pleistocene was followed by renewed activity about 800,000 years ago that continued into the Holocene. The latest dated eruption took place about 3400 years ago.

Sanbe
Honshu
Pyroclastic cone
Sanbe stratovolcano in SW Honshu, along the Japan Sea coast, is also known as Sambe volcano. The summit of Sanbe is cut by a small caldera about 1 km in diameter. The highest point on the dacitic-to-andesitic volcano is 1126-m-high O-Sanbe, at the northern end of the complex. Sanbe has had several large explosive eruptions during the Pleistocene and one strong Holocene eruption from Taihei-zan lava dome about 3700 years ago. This eruption was accompanied by pyroclastic flows that swept down the NE-to-SE flanks and traveled 9 km down the Hayamizu River to the SW. Younger, undated eruptions have also occurred (Machida and Arai, 1992).

Oki-Dogo
West of Honshu (Japan)
Shield volcano
Cinder cone
The Oki-Dogo islands, north of the SW Honshu city of Matsue, are one of several locations of Holocene volcanism on islands of the Japan Sea off the west coast of Japan. The Oki-Dogo islands are largely Pleistocene in age, and dated rocks range from about 800,000 to 300,000 years old. Tomita (1969) described a shield volcano and cinder cone that have produced Holocene basalts. The alkaline basalts on Oki-Dogo are related to the opening of the Japan Sea and contain abundant mantle-derived xenoliths. The Daimanji-san lava flow overlies alluvial gravel containing an ancient water-jar. The name Takuhi-yama ("Burning Mountain") may record a tradition of an eruption.

Izu-Tobu
Submarine volcanoes
The Izu-Tobu volcano group (Higashi-Izu volcano group) is scattered over a broad, plateau-like area of more than 400 sq km on the east side of the Izu Peninsula. Construction of several stratovolcanoes continued throughout much of the Pleistocene and overlapped with growth of smaller monogenetic volcanoes beginning about 300,000 years ago. About 70 subaerial monogenetic volcanoes formed during the last 140,000 years, and chemically similar submarine cones are located offshore. These volcanoes are located on a basement of late-Tertiary volcanic rocks and related sediments and on the flanks of three Quaternary stratovolcanoes: Amagi, Tenshi, and Usami. Some eruptive vents are controlled by NW-SE- or NE-SW-trending fissure systems. Thirteen eruptive episodes have been documented during the past 32,000 years. Kawagodaira maar produced pyroclastic flows during the largest Holocene eruption about 3000 years ago. The latest eruption occurred in 1989, when a small submarine crater was formed NE of Ito City.

Hakone
Complex volcano
Calderas
Hakone volcano is truncated by two overlapping calderas, the largest of which is 10 x 11 km wide. The calderas were formed as a result of two major explosive eruptions about 180,000 and 49,000-60,000 years ago. Scenic Lake Ashi lies between the SW caldera wall and a half dozen post-caldera lava domes that were constructed along a SW-NE trend cutting through the center of the calderas. Dome growth occurred progressively to the south, and the largest and youngest of these, Kami-yama, forms the high point of Hakone. The calderas are breached to the east by the Haya-kawa canyon. A phreatic explosion about 3000 years ago was followed by collapse of the NW side of Kami-yama, damming the Haya-kawa valley and creating Lake Ashi. The latest magmatic eruptive activity at Hakone about 2900 years ago produced a pyroclastic flow and a lava dome in the explosion crater, although phreatic eruptions took place as recently as the 12-13th centuries AD. Seismic swarms have occurred at Hakone during the 20th century. Lake Ashi, along with major thermal areas in the caldera, forms a popular resort area SW of Tokyo.

Fuji
The conical form of Fuji-san, Japan's highest and most noted volcano, belies its complex origin. The modern postglacial stratovolcano is constructed above a group of overlapping volcanoes, remnants of which form irregularities on Fuji's profile. Growth of the Younger Fuji volcano began with a period of voluminous lava flows from 11,000 to 8000 years before present (BP), accounting for four-fifths of the volume of the Younger Fuji volcano. Minor explosive eruptions dominated activity from 8000 to 4500 BP, with another period of major lava flows occurring from 4500 to 3000 BP. Subsequently, intermittent major explosive eruptions occurred, with subordinate lava flows and small pyroclastic flows. Summit eruptions dominated from 3000 to 2000 BP, after which flank vents were active. The extensive basaltic lava flows from the summit and some of the more than 100 flank cones and vents blocked drainages against the Tertiary Misaka Mountains on the north side of the volcano, forming the Fuji Five Lakes, popular resort destinations. The last confirmed eruption of this dominantly basaltic volcano in 1707 was Fuji's largest during historical time. It deposited ash on Edo (Tokyo) and formed a large new crater on the east flank.

Kita Yatsuga-take
Kita-Yatsuga-take (North Yatsuga-take) is a group of stratovolcanoes and lava domes at the NW end of the NNW-SSE-trending Yatsuga-take volcanic massif. The basaltic-to-dacitic Kita Yatsuga-take volcanic group contains the Tateshina, Yoko-dake, Shimagare-yama, Chausu-yama and Futago-mine volcanoes. Tateshina-yama is sometimes known as Suwa Fuji because of its conical profile. A large lava flow forms the Tateshina-kogen plateau south of Tateshina and Yoko-dake volcanoes. A debris avalanche from edifice collapse in 888 AD created Matsubara Lake on the east side of the massif. Yoko-dake lava dome, capped by eight small craters, has been active into the Holocene. The most recent eruption took place about 800 years ago, when ash emission accompanied emplacement of a small lava flow.

On-take
The massive On-take stratovolcano, the second highest volcano in Japan, lies at the southern end of the Northern Japan Alps. On-take is constructed within a largely buried 4 x 5 km caldera and occupies the southern end of the Norikura volcanic zone, which extends northward through Norikura volcano to Yake-dake volcano. The older volcanic complex consisted of at least four major stratovolcanoes constructed from about 680,000 to about 420,000 years ago, after which On-take was inactive for more than 300,000 years. The broad, elongated summit of the younger edifice is cut by a series of small explosion craters along a NNE-trending line. Several phreatic eruptions from On-take post-date the roughly 7300-year-old Akahoya tephra from Kikai caldera. On-take's first historical eruption took place in 1979. A non-eruptive landslide in 1984 produced a debris avalanche and lahar that swept down valleys south and east of the volcano. Ascent of the 3063-m-high On-take is one of the major objects of religious pilgrimage in central Japan.

Haku-san
Haku-san, along with Fuji-san and On-take, is one of Japan's three most sacred mountains. It is a complex andesitic-dacitic stratovolcano overlooking the Japan Sea. The 2702-m-high Haku-san was constructed over a high basement of sedimentary rocks in a region of very heavy snowfall that has contributed to erosional dissection. Holocene eruptions have consisted of phreatic or phreatomagmatic explosions from several summit craters. Partial collapse of the summit produced a debris avalanche down the east flank during the mid-Holocene. Historical eruptions were recorded over almost a thousand-year period until the 17th century.

Norikura
Norikura volcano consists of an elongated group of small andesitic stratovolcanoes and craters arranged along a N-S line above a ridge crest in the southern part of the Northern Japan Alps. The 3026-m-high andesitic-to-dacitic volcano is the third highest in Japan and lies at the center of the Norikura volcanic zone extending from Yake-dake on the north to On-take on the south. Early eruptions occurred at both the northern and southern ends of the present-day volcano, forming stratovolcanoes that have been largely buried by later southward-migrating eruptions. Norilura-ake was active during the early Holocene, and the last eruption took place about 2000 years ago.

Yake-dake
Yake-dake rises above the popular resort of Kamikochi in the Northern Japan Alps. The small dominantly andesitic stratovolcano, one of several Japanese volcanoes named Yake-dake or Yake-yama ("Burning Peak" or "Burning Mountain"), was constructed astride a N-S-trending ridge between the older volcanoes of Warudani-yama and Shiratani-yama. Akandana-yama, about 4 km SSW of Yake-dake, is a stratovolcano with lava domes that was active into the Holocene. A 300-m-wide crater is located the summit of Yake-dake, and explosion craters are found on the SE and northern flanks. Frequent small-to-moderate phreatic eruptions have occurred during the 20th century. On February 11, 1995, a hydrothermal explosion in a geothermal area killed two persons at a highway construction site.

Washiba-Kumonotaira
Shield volcanoes
Lava domes ?
The Washiba-Kumonotaira volcano group consists of a cluster of small shield volcanoes with possible lava domes in a remote area in the heart of the Northern Japan Alps. A tephra layer consisting of accretionary lapilli and fresh volcanic bombs that originated from the Washiba-ike explosion crater overlies the 6300-year-old Akahoya Ash from Kikai volcano. The Washiba-ike tephra is considered to have an approximate age of about 4000 BC (Hayakawa 1996, pers. comm.).

Tate-yama
Caldera (erosion)
Explosion craters
Tate-yama volcano is a dissected andesitic-to-dacitic stratovolcano on a plateau surrounded by high peaks of the North Japan Alps. Tate-yama is named for the granite-and-gneiss peak of Tate-yama, which lies immediately to the east. Formation of a 4-km-wide erosional caldera was followed by repeated eruptions of lava and pyroclastics forming the Midagahara plateau that was later dissected by the Yu-kawa river. Holocene eruptions have been restricted to small phreatic explosions that formed craters. A minor historical eruption occurred in the 19th century. An earthquake swarm took place in 1990. Hot springs occur in seven locations on the floor of the poorly defined erosional caldera.

Niigata-Yake-yama
Explosion craters
Niigata-Yake-yama, one of several Japanese volcanoes named Yake-yama ("Burning Mountain"), is a very young andesitic-to-dacitic lava dome in Niigata prefecture in central Honshu, near the Japan Sea. The small volcano rises to 2400 m and was constructed on a base of Tertiary mountains 2000 m high beginning about 3100 years ago. Three major magmatic eruptions took place in historical time, producing pyroclastic flows and surges and lava flows that traveled mainly down the Hayakawa river valley to the north and NW. The first of these eruptions took place about 1000 years ago (in 887 and possibly 989 AD) and produced the Hayakawa pyroclastic flow, which traveled about 20 km to reach the Japan Sea, and the massive Mae-yama lava flow, which traveled about 6.5 km down the Hayakawa river valley. The summit lava dome was emplaced during the 1361 eruption, and the last magmatic eruption took place in 1773 AD. Eruptive activity since 1773 has consisted of relatively minor phreatic explosions from several radial fissures and explosion craters that cut the summit and flanks of the dome.

Myoko
Myoko is a steep-sided stratovolcano north of Nagano City that overlooks the popular resort of Lake Nojiri below its SE flank. A 3-km-wide caldera breached widely to the east is filled by a flat-topped lava dome that forms the basaltic-to-dacitic volcano's summit. Myoko volcano was constructed during four stages beginning about 300,000 years ago, each evolving from basaltic to andesitic and dacitic eruptions. The latest eruptive stage began about 43,000 years ago. Several episodes of edifice collapse at Myoko during the late Pleistocene to early Holocene have produced major debris avalanches that traveled to the east and NE. Myoko produced pyroclastic flows down the eastern flanks of the volcano during the mid Holocene about 5800 and 4200 years ago, and the latest dated eruption produced pyroclastic surges about 2800-2500 years ago. No historical eruptions are known at Myoko, but constant solfataric activity occurs between the dome and the south caldera wall at a place where sulfur was once mined.

Asama
Asama, Honshu's most active volcano, overlooks the resort town of Karuizawa, 140 km NW of Tokyo. The volcano is located at the junction of the Izu-Marianas and NE Japan volcanic arcs. The modern cone of Maekake-yama forms the summit of the volcano and is situated east of the horseshoe-shaped remnant of an older andesitic volcano, Kurofu-yama, which was destroyed by a late-Pleistocene landslide about 20,000 years before present (BP). Growth of a dacitic shield volcano was accompanied by pumiceous pyroclastic flows, the largest of which occurred about 14,000-11,000 years BP, and by growth of the Ko-Asama-yama lava dome on the east flank. Maekake-yama, capped by the Kama-yama pyroclastic cone that forms the present summit of the volcano, is probably only a few thousand years old and has an historical record dating back at least to the 11th century AD. Maekake-yama has had several major plinian eruptions, the last two of which occurred in 1108 (Asama's largest Holocene eruption) and 1783 AD.
Smithsonian Volcano Information | Asama Volcano Observatory | Geological Survey of Japan

Kusatsu-Shirane
The summit of Kusatsu-Shirane volcano, located immediately north of Asama volcano, consists of a series of overlapping pyroclastic cones and three crater lakes. The andesitic-to-dacitic volcano was formed in three eruptive stages beginning in the early to mid Pleistocene. The Pleistocene Oshi pyroclastic flow produced extensive welded tuffs and non-welded pumice that covers much of the east, south and SW flanks. The latest eruptive stage began about 14,000 years ago. All historical eruptions have consisted of phreatic explosions from the acidic crater lakes or their margins. Fumaroles and hot springs that dot the volcano's flanks have strongly acidified many rivers draining from the volcano. The crater was the site of active sulfur mining for many years during the 19th and 20th centuries.

Shiga
The Shiga volcanic complex immediately north of Kusatsu-Shirane volcano consists of a group of small andesitic shield volcanoes and pyroclastic cones. A large lava plateau was erupted between about 300,000 to 200,000 years ago. The latest activity occurred between about 250,000 and 10,000 years ago (Nakano et al., 2001-). The Shiga-Kogen (Shiga Plateau) area is a popular winter sports destination.

Haruna
Haruna volcano is truncated by a small summit caldera containing the symmetrical post-caldera pyroclastic cone of Haruna-Fuji. Haruna-san volcano dates back prior to 300,000 years ago and had caldera-producing eruptions at about 200,000 and 40,000 years ago. Viscous lava flows and lava domes were subsequently extruded within and around the caldera, the western side of which is currently partially filled by Lake Haruna. The Futatsu-dake lava dome east of the caldera was the source of two large explosive eruptions during the 6th century AD.

Akagi
The broad, low dominantly andesitic Akagi volcano rises above the northern end of the Kanto Plain. It contains an elliptical, 3 x 4 km summit caldera with post-caldera lava domes arranged along a NW-SE line. Lake Ono is located at the NE end of the caldera. An older stratovolcano was partially destroyed by edifice collapse, producing a debris-avalanche deposit along the south flank. A series of large plinian eruptions accompanied growth of a second stratovolcano during the Pleistocene. Construction of the central cone in the late-Pleistocene summit caldera began following the last of the plinian eruptions about 31,000 years ago. During historical time unusual activity was recorded on several occasions during the 9th century, but reported eruptions in 1251 and 1938 are considered uncertain.

Hiuchi
Hiuchi volcano lies in Nikko National Park and erupted the 8 cu km Hiuchigatake-Nanairi tephra and pyroclastic flow deposit about 170,00-160,000 years ago. Two lava domes at the southern end of the summit of Hiuchi stratovolcano overlook Ozenuma lake, a popular hiking destination in the national park. The southern of the two domes, Akanagure, produced a series of viscous lava flows about 3500 years ago that extend to the southern and western flanks the volcano. The northern dome, Mi-ike, was the source of a tephra layer correlated with a report of historical activity in 1544 (Hayakawa, 1994b).

Nikko-Shirane
Nikko-Shirane is a relatively small, 2578-m-high andesitic volcano consisting of a group of four lava domes resting on a shield volcano that rises to the NW of scenic Lake Chuzenji in Nikko National Park. All historical eruptions, recorded during the 17th-20th centuries, have consisted of phreatic explosions from Shirane-san, the youngest lava dome. Viscous lava flows with prominent levees from the underlying shield volcano Keizuka-yama were responsible for the formation of several scenic lakes north of the volcano.

Nantai
Nantai stratovolcano rises above the north shore of Lake Chuzenji in Nikko National Park, and forms a backdrop to the renowned temple complex at Nikko. Lava flows from the early stage of the construction of Nantai volcano dammed up the Daiyo River, forming Lake Chuzenji. The dramatic Kegon waterfall plunges over this barrier. Nantai has an asymmetrical profile when viewed from the west as a result of late-stage collapse of the north side of the volcano. Two major late-stage eruptions ejected large amounts of scoriae, followed by the emission of pyroclastic flows. A pumice-flow eruption was said to have occurred during the Holocene (Ishikawa et al., 1957), although Nakano et al (2001-) listed activity from 25,000 to 12,000 years ago. The latest effusive activity of Nantai produced the Osawa lava flow, a thick, viscous dacitic flow that traveled from the breached crater down the north flank.

Omanago Group
The Omanago volcano group consists of a series of five closely spaced lava domes that were constructed north and NW of Nantai volcano in Nikko National Park. The highest of the dacitic domes is 2367-m-high Omanago, which later erupted andesitic lavas. Mitsu-dake lava dome, which overlooks the hot spring resort of Lake Yunoko, was mapped as Holocene in age (Japan Association of Quaternary Research, 1987). Mitsu-dake was constructed on a southerly dipping slope, so that the southern of its two flat-topped domes is lower, and is overlapped by sediments of the Senjogahara plain.

Takahara
Takahara is a small stratovolcano with lava domes located SW of Nasu volcano and NNW of Utsunomiya city in central Honshu. The basaltic-to-dacitic volcano lies within the Shiobara caldera, which was formed during the late Pleistocene at the time of the eruption of the Otawara pumice-flow deposit. The latest dated eruption of Takahara took place about 6500 years ago along the NW-SE-trending Yumoto-Shiobara fissure system within the caldera. Eruptions along this fissure initially produced the phreatic Takahara-Uenohara tephra deposit, which was distributed primarily to the east. The symmetrical Fuji-san lava dome, one of many conical volcanoes named after Japan's renowned Mount Fuji, was extruded at the end of the eruption.

Nasu
The Nasu volcanic group consists of a N-S-trending cluster of stratovolcanoes and lava domes at the north end of the Kanto Plain. Nasu volcanic activity dates back about 500,000 years. Growth of three large basaltic-to-dacitic stratovolcanoes with life spans of about 200,000 years was followed by construction of three smaller andesitic stratovolcanoes, Asahi-dake, Futamata-yama, and Chausu-dake. Activity during the last 55,000 years included the collapse of Asahi-dake volcano about 30-40,000 years ago producing the massive Ofuji-san debris-avalanche deposit, which blankets a broad area SE of the volcano. The youngest volcano, Chausu-dake, began forming about 16,000 years ago. Six magmatic eruptions took place since then, the latest in 1408-1410, when the youngest summit lava dome, Chausu-dake, was formed. These eruptions produced block-and-ash flows and concluded with the extrusion of lava flows. Smaller phreatic eruptions have occurred every few hundred years during the past 5000 years.

Numazawa
Numazawa is a small, 2-km-wide dominantly dacitic-to-rhyolitic caldera constructed within an older Pliocene caldera. Eruptions of the 110,00 yrs Before Present (BP) rhyolitic Shibahara pyroclastic-fall deposit and the 71,000 BP dacitic Mukuresawa lava dome were followed by the dacitic plinian Mizunuma eruption about 45,000 years before present (BP), emplacement of the Sozan lava dome at 43,000 BP and the So-zan lava dome at about 20,000 BP. The Numazawako pumice flow and plinian eruption about 4600 years BP resulted in formation of the 1.5 x 2 km Numazawako caldera, now largely filled by a caldera lake.

Bandai
One of Japan's most noted volcanoes, Bandai-san rises above the north shore of Lake Inawashiro. The Bandai complex is formed of several overlapping andesitic stratovolcanoes, the largest of which is O-Bandai. Ko-Bandai volcano, which collapsed in 1888, was formed about 50,000 years ago. O-Bandai volcano was constructed within a horseshoe-shaped caldera that formed about 40,000 years when an older volcano collapsed, forming the Okinajima debris avalanche, which traveled to the SW and was accompanied by a plinian explosive eruption. The last magmatic eruption at Bandai took place more than 25,000 years ago, but four major phreatic eruptions have occurred during the past 5000 years, two of them in historical time, in 806 and 1888. Seen from the south, Bandai presents a conical profile, but much of the north side of the volcano is missing as a result of the collapse of Ko-Bandai volcano during the 1888 eruption, in which a debris avalanche buried several villages and formed several large lakes.

Adatara
The broad forested massif of Adatara volcano is located east of Bandai volcano, about 15 km SW of Fukushima city. Adatara consists of a group of basaltic-to-andesitic stratovolcanoes and lava domes that rise above Tertiary rocks on the south and abut Azuma volcano on the north. Adatara was constructed in three main stages that began about 550,000, 350,000, and 200,000 years ago. The high point of the complex is 1718-m-high Minowa-yama, a dome-shaped stratovolcano north of Tetsu-zan, the currently active stratovolcano. Numanotaira, the active summit crater, is surrounded by hot springs and fumaroles and is breached by the Io-gawa river ("Sulfur River") on the west. Seventy-two workers of a sulfur mine in the summit crater were killed during an eruption in 1900. Historical eruptions have been restricted to the 1.2-km-wide, 350-m-deep Numono-taira crater.

Azuma
The Azuma volcanic group consists of a cluster of stratovolcanoes, shield volcanoes, lava domes, and pyroclastic cones. The andesitic and basaltic complex was constructed in two E-W rows above a relatively high basement of Tertiary sedimentary rocks and granodiorites west of Fukushima city. Volcanic activity has migrated to the east, with the Higashi-Azuma volcano group being the youngest. The symmetrical Azuma-Kofuji crater and a nearby fumarolic area on the flank of Issaikyo volcano are popular tourist destinations. The Azuma complex contains several crater lakes, including Goshiki-numa and Oke-numa. Historical eruptions, mostly small phreatic explosions, have been restricted to Issaikyo volcano at the northern end of the Higashi-yama group.

Zao
The Zao volcano group, the most active of northern Honshu, consists of a complex cluster of stratovolcanoes straddling the Pacific Ocean-Japan Sea divide. The Pleistocene Ryuzan volcano forms the western Zao group (Nishi-Zao), and Byobu and Fubo volcanoes form the southern Zao group (Minami-Zao). The complex was constructed over granitic basement rocks as high as 1500 m and thus has a relatively small volume. The 7 cu km Zao volcano proper forms the central ao group (Chuo-Zao), a volcanic complex topped by several lava domes and the Goshiki-dake tuff cone, aligned along a NW-SE trend. Several episodes of edifice collapse produced debris avalanches during the Pleistocene. Goshiki-dake contains the active Okama crater, filled with a colorful, strongly acidic crater lake (pH 1.3). It has been the source of most of the frequent historical eruptions of Zao volcano, which date back to the 8th century AD.

Hijiori
Hijiori caldera is a small, inconspicuous caldera located NE of the massive Pleistocene Gassan volcano. The low 2.5-km-wide caldera formed during a large eruption about 10,300 radiocarbon years ago. This eruption was accompanied by dacitic pyroclastic flows and tephra fall that extended to the east and reached the Pacific coast and growth of a lava dome. Small local tephra deposits overlie lacustrine deposits. Hot springs occur at Hijiori, and caldera lake deposits have undergone extensive hydrothermal alteration. Hijiori has been evaluated as a potential geothermal energy source using hot dry rock as a heat source.

Narugo
Narugo (also known as Naruko) is a poorly defined, 5.5 x 7 km caldera NW of the city of Sendai. The caldera, formed during eruptions about 73,000 and 45,000 years ago, contains a cluster of four dacitic lava domes of Holocene age surrounding the 400-m-wide lake-filled Katanuma crater. The highest of the low, but steep-sided lava domes, Oga-dake, lies SE of the lake and reaches only 470 m above sea level. Oga-dake and Kurumiga-dake domes are capped by conglomerates and mudstones uplifted during dome growth. The only known eruption at Narugo in historical time occurred in 837 AD. Water vapor and sulfur-dioxide gas emission occurs from Shurado crater on Toyagamori lava dome west of the lake and from the bottom of the crater lake, which is one of the most acidic in Japan, with a pH of 1.6. Solfataras are found on the western shore of Katanuma, and sulfur is mined from sediments on the lake floor.

Onikobe
Honshu (Japan)
Onikobe caldera, located SW of Kurikoma volcano, is one of the few calderas in Japan with evidence of ring fractures and a resurgent dome. The Takahinata lava dome was last active about 350,000 years ago according to a fission-track date. Onikobe was active until about 0.2 million years ago (Nakano et al., 2001-). Geysers were said to be discovered about 1700 years ago at Onikobe, and geysers and hot springs are present today within the caldera.

Kurikoma
The summit of Kurikoma volcano is cut by a 4-km-wide caldera breached to the north that is partially filled by the Tsurugi-dake central cone, once mined for sulfur. The complex andesitic-to-dacitic stratovolcano was constructed over a relatively high basement of welded and unwelded Tertiary dacitic tuffs and sedimentary rocks and thus has a smaller volume than its height suggests. Early stage eruptions beginning about 500,000 years ago produced lava flows to the north and south, followed by growth of the Higashi-Kurikoma (East Kurikoma) stratovolcano. Magusa-dake volcano on the western side of the complex was active until about 100,000 years ago. Construction of the main cone concluded with lava flows to the east, SE, and west. Daichigamori lava dome and Aguroshi-yama pyroclastic cone are located on the southern flank. Minor phreatic eruptions have occurred in historical time from the central cone.

Chokai
Massive Chokai volcano, the largest of NE Honshu, overlooks the Japan Sea. Chokai is composed of two overlapping stratovolcanoes with a conical profile that has given it the local names Akita-Fuji or Dewa-Fuji. The summit of the gently sloping western volcano (Nishi-Chokai) is cut by a large horseshoe-shaped caldera breached to the south, whose floor contains lava domes. The younger eastern volcano (Higashi-Chokai) began forming about 20,000 years ago. It was cut by another large horseshoe-shaped caldera, breached to the north. During an eruption about 2600 years ago it was the source of the voluminous Kisakata debris avalanche, which reached the Pacific coast. Two post-caldera lava domes have been constructed at the upper SE end of the caldera. Intermittent reports of historical eruptions at Chokai date back to the 6th century AD.

Akita-Komaga-take
Two calderas partially filled by basaltic cones cut the summit of Akita-Komaga-take volcano. The larger southern caldera is 1.5 x 3 km wide and has a shallow sloping floor that is drained through a narrow gap cutting the SW caldera rim. On its northern side the southern caldera borders a smaller more circular 1.2-km-wide caldera, whose rim is breached widely to the NE. The two calderas were formed following explosive eruptions at the end of the Pleistocene, between about 13,500 and 11,600 years ago. Two cones, Me-dake and Ko-dake, occupy the NE corner of the southern caldera, whose long axis trends NE-SW. The highest point of the volcano is a cone within the northern caldera, 1637-m-high Komaga-take (also known as Omae-dake or Oname-dake), which has produced lava flows to the north and east and has a 100-m-wide summit crater. Small-scale historical eruptions have occurred from cones and fissure vents inside the southern caldera.

Iwate
Viewed from the east, Iwate volcano has a symmetrical profile that invites comparison with Fuji, but on the west an older cone is visible containing an oval-shaped, 1.8 x 3 km caldera. After the growth of Nishi-Iwate volcano beginning about 700,000 years ago, activity migrated eastward to form Higashi-Iwate volcano. Iwate has collapsed seven times during the past 230,000 years, most recently between 739 and 1615 AD. The dominantly basaltic summit cone of Higashi-Iwate volcano, Yakushi-dake, is truncated by a 500-m-wide crater. It rises well above and buries the eastern rim of the caldera, which is breached by a narrow gorge on the NW. A central cone containing a 500-m-wide crater partially filled by a lake is located in the center of the oval-shaped caldera. A young lava flow from Yakushi-dake descended into the caldera, and a fresh-looking lava flow from the 1732 eruption traveled down the NE flank.

Hachimantai
The summit of Hachimantai volcano forms an undulating plateau surrounded by steep slopes. Hachimantai was constructed from widely scattered vents during the Pleistocene and is capped with andesitic lavas from vents in the center of the complex. Circular craters are located near Komono-more and Mokko-dake in the center of the plateau. The craters are youthful looking, but have not been dated. Hayakawa (1996, pers. comm.) considered Hachimantai to be of possible Holocene age. No historical eruptions have been recorded, but active solfataras are found on the western and southern flanks.

Akita-Yake-yama
One of several Japanese volcanoes named Yake-yama ("Burning Mountain"), Akita-Yake-yama is the most recently active of a group of coalescing volcanoes in NW Honshu immediately west of Hachimantai volcano. The main volcano, Yake-yama, contains a small lava dome in its 600-m-wide summit crater. Tsugamori volcano to the east is a stratovolcano of roughly the same height as Yake-yama and has a 2-km-wide crater breached to the NE. The flat-topped parasitic lava dome of Kuroshimori lies 4 km south of Yake-dake. Tamagawa Spa at the western foot, one of several thermal areas, is strongly radioactive. The last magmatic eruption at Akita-Yake-yama formed the Onigajo lava dome in the summit crater about 5000 years ago. The only known historical activity has consisted of somewhat uncertain 19th-century eruptions and mild phreatic eruptions in the 20th century.

Kanpu
The small Kanpu stratovolcano on the Oga Peninsula along the Japan Sea coast NW of Akita City was formed in four stages during the late Pleistocene and Holocene. The bulk of the volcano was formed in the third stage as a result of accumulation of thick andesitic lava flows. A pumice eruption at the end of the third stage about 2700 years before present was followed by a pyroclastic flow. Collapse of the central part of the volcano was followed by extrusion of basaltic lava flows in the final stage. An uncertain report suggesting that an eruption may have occurred at the time of a large earthquake in 1810 AD has been discredited.

Megata
Maars
Megata, a group of three small maars along the tip of the Oga Peninsula in NW Honshu, has been active during the Holocene (Ishikawa et al., 1957). Lakes 300-600 m wide fill the basaltic-to-dacitic maars, which are a noted locality for mantle-derived xenoliths. Ichinomegata, the easternmost, largest, and oldest of the three maars, is 600 m in diameter. Ninomegata and Sannomegata are located immediately east and south of Toga Bay. The maars are mostly late Pleistocene in age, but pottery from roughly 4000 years before present (Jomon Period) has been found within tephra layers from the maars (Murayama, 1987).

Iwaki
Iwaki volcano, symmetrical on all but its western flanks, has been called the Fuji-san of the Tsugaru district. The 2-km-wide summit crater is filled by a lava dome flanked by six explosion craters. Three lava domes are found on the western and southern flanks of the andesitic volcano, the NW-most active volcano in Honshu. Historical eruptions have been reported at Iwaki since 1600 AD and have consisted primarily of small-to-moderate phreatic explosions.

Towada
The dramatic, 11-km-wide, lake-filled Towada caldera formed during as many as six major explosive eruptions over a 40,000-year period ending about 13,000 years ago. Pre-caldera eruptive activity at Towada dates back to about 2 million years ago and produced basaltic-to-dacitic lava cones. Following late-Pleistocene andesitic-to-rhyolitic caldera-forming eruptions, the basaltic Ninokura stratovolcano grew in the SSE section of the caldera. The successive dacitic-to-rhyolitic Goshikiiwa explosive eruptions led to the formation of the roughly 2-km-wide Nakanoumi caldera, whose SW and NE rims form dramatic peninsulas extending into Lake Towada. The andesitic-to-dacitic Ogura-yama lava dome was built over the NE rim of Nakanoumi. The latest eruption of Towada took place in 915 AD, when eruptions from Ogura-yama produced widespread ashfalls and pyroclastic flows.

Hakkoda Group
The basaltic-to-rhyolitic Hakkoda volcano includes 14 stratovolcanoes and lava domes south of Mutsu Bay at the northern end of Honshu. The NE rim of an 8-km-wide Pleistocene caldera forms an arcuate ridge across a flat caldera-floor moat NE of the Hakkoda group volcanoes, which bury the SE caldera wall. A northern group of volcanoes, constructed within the caldera, appears to be younger than the southern group. Hakkoda-Odake, Ido-dake, and Tsurugi-dake have well-preserved craters. Akakura-dake has a 1-km-wide explosion crater breached to the north. No historical eruptions are known of the Hakkoda group, although an active solfatara occurs at Ido-dake, and hot springs are found at several locations within the caldera. Three minor phreatic eruptions were documented from Jigoku-numa on the SW flank of Odake volcano from the 13th-17th centuries. Three soldiers on a training mission in July 1997 were killed by inhalation of volcanic gas.

Osore-yama
Osore-yama, on the Shimokita Peninsula in northernmost Honshu, contains a 5-km-wide caldera partly occupied by a shallow lake that drains through the north caldera wall. Dissected lava domes ring the caldera floor. The andesitic-to-dacitic Osore-yama is largely Pleistocene in age, with activity dating back about 800,000 years. The last identified distal tephra deposit was erupted during the late Pleistocene. The only report of historical activity was in a Tohoku district travel document published in 1787, which stated that Yake-yama in Mutsu country (Osore-yama) had erupted. Older residents reported that large fires and clouds were sometimes seen from the summit, accounting for the volcano's local name, Yake-yama, or "Burning Mountain" (Murayama, 1987). Earthquake swarms have been documented at Osore-yama during the second half of the 20th century, and magma bodies have been detected beneath the volcano.

Mutsu-Hiuchi-dake
Honshu (Japan)
Mutsu-Hiuchi-dake, on the Shimokita Peninsula, is the northernmost volcano on the island of Honshu. The 781-m-high andesitic-dacitic stratovolcano is Pleistocene in age, with dated activity during an interval ranging from about 700,000 to 50,000 years ago, although fumarolic activity continues at the volcano.

Izu, Volcano, & Mariana Islands

Oshima
Izu Islands (Japan)
Oshima volcano in Sagami Bay, east of the Izu Peninsula, is the northernmost of the Izu Islands. The broad, low stratovolcano forms an 11 x 13 km island and was constructed over the remnants of three dissected stratovolcanoes. It is capped by a 4-km-wide caldera with a central cone, Mihara-yama, that has been the site of numerous historical eruptions. More than 40 parasitic cones are located within the caldera and along two parallel rift zones trending NNW-SSE. Although Oshima is a dominantly basaltic volcano, strong explosive activity has occurred at intervals of 100-150 years throughout the past few thousand years. Historical activity at Oshima dates back to the 7th century AD. A major eruption in 1986 produced spectacular lava fountains up to 1600 m height and a 16-km-high subplinian eruption column; more than 12,000 persons were evacuated from the island.

To-shima
Izu Islands (Japan)
The small 2 x 2.4 km island of To-shima is located in the northern Izu Islands south of Oshima Island and lies about 20 km west of the main volcanic front. Steep cliffs up to 300 m high ring the basaltic-to-basaltic andesite island on three sides. The 508-m-high summit of the island is asymmetrically located opposite the more gentle slopes of the northern side of the island, where the village of To-shima is located. The latest known eruption of To-shima stratovolcano occurred sometime between about 9000 and 4000 years ago, producing a lava flow from Kajiana crater.

Nii-jima
Izu Islands (Japan)
Pumice cone
The elongated island of Nii-jima, SSW of Oshima, is 11 km long and only 2.5 km wide. It is comprised of eight low rhyolitic lava domes that are clustered in two groups at the northern and southern ends of the island, separated by a low, flat isthmus. The flat-topped domes give the island the appearance of two large plateaus bounded by steep cliffs. The Mukai-yama complex at the southern end of the island and Achi-yama lava dome at the northern end were formed during Nii-jima's only historical eruptions in the 9th century AD. Shikine-yama and Zinai-to domes form small islands immediately to the SW and west of Nii-jima, respectively, during earlier stages of volcanism. Earthquake swarms occurred at Nii-jima during the 20th century.

Kozu-shima
A cluster of rhyolitic lava domes and associated pyroclastic deposits form the small 4 x 6 km island of Kozu-shima in the northern Izu Islands. Kozu-shima lies along the Zenisu Ridge, one of several en echelon ridges oriented NE-SW, transverse to the trend of the northern Izu arc. The youngest and largest of the 18 lava domes, 574-m-high Tenjo-yama, occupies the central portion of the island. Most of the older domes, some of which are Holocene in age, flank Tenjo-yama to the north, although late-Pleistocene domes are also found at the southern end of the island. Only two possible historical eruptions, from the 9th century, are known. A lava flow may have reached the sea during an eruption in 832 AD. Tenjo-san lava dome was formed during a major eruption in 838 AD that also produced pyroclastic flows and surges. Earthquake swarms took place at Kozu-shima during the 20th century.

Miyake-jima
The circular, 8-km-wide island of Miyake-jima forms a low-angle stratovolcano that rises about 1100 m from the sea floor in the northern Izu Islands about 200 km SSW of Tokyo. The basaltic volcano is truncated by small summit calderas, one of which, 3.5 km wide, was formed during a major eruption about 2500 years ago. Parasitic craters and vents, including maars near the coast and radially oriented fissure vents, dot the flanks of the volcano. Frequent historical eruptions have occurred since 1085 AD at vents ranging from the summit to below sea level, causing much damage on this small populated island. After a three-century-long hiatus ending in 1469, activity has been dominated by flank fissure eruptions sometimes accompanied by minor summit eruptions. A 1.6-km-wide summit caldera was slowly formed by subsidence during an eruption in 2000; by October of that year the crater floor had dropped to only 230 m above sea level.

Mikura-jima
Mikura-jima is a small steep-sided island located between the more well-known Miyake-jima and Hachijo-jima volcanoes. O-yama forms the 851-m-high summit of the basaltic-to-andesitic island, which is surrounded by cliffs up to about 500 m high and dissected on the southern-to-eastern sides. The sparsely populated island consists of a large stratovolcano with lava domes on the SE side. Several small sea stacks are located immediately offshore, including one 73 m high off the SE tip of the island. Growth of the stratovolcano took place until about 7000 years ago, and the latest activity occurred about 6000 years ago, when explosive eruptions and pyroclastic surges accompanied lava dome growth.

Kurose Hole
Summit Elev: -107 m
Kurose Hole, between Mikura and Hachijo-jima islands, is a nearly circular 5-7 km wide submarine caldera with a 600-760 m deep caldera floor. A flat-topped somma rim rises to within 107 m of the sea surface. Large amounts of dacitic pumice were recovered from dredges along the inner caldera wall. Kurose caldera has a youthful morphology, but the age of its most recent eruption is not known.

Hachijo-jima
Hachijo-jima, in the central Izu Islands about 300 km south of Tokyo, consists of two small Quaternary dominantly basaltic stratovolcanoes forming an elongated NW-SE-trending island. The eroded Pleistocene-to-Holocene Higashi-yama volcano occupies the SE end of the 14-km-long island, and the symmetrical Holocene Nishi-yama volcano the NW end. Parasitic cones occur on the SE flank of Nishi-yama. The small volcanic island of Ko-jima lies several km to the west of Hachijo-jima. Growth of Higashi-yama began several tens of thousands of years ago, and included the formation of two small calderas. The initial submarine and early subaerial eruptions of Nishi-yama took place from 10,000 to 8000 years before present (BP). Its latest major activity, from the early Holocene until about 4000 years BP, was restricted to flank eruptions. Historical eruptions of Hachijo-jima, recorded since the 15th century, have been restricted to the summit of Nishi-yama and a submarine vent of unknown location.

Aoga-shima
The small 2.5 x 3.5 km dominantly basaltic island of Aoga-shima is surrounded by steep cliffs and contains a small 1.7 x 1.5-km-wide caldera. Two pyroclastic cones were formed inside the caldera during the volcano's latest eruption from 1780 to 1785. Growth of Aoga-shima volcano began with construction of the Kurosaki stratovolcano in the NW part of the island, after which the main stratovolcano began growing in the SE part of the island. Both summit and flank vents produced pyroclastic surges and lava flows. Late in the construction of the main cone a 1-1.5 km crater was formed on the SE flank. About 3000 years ago pyroclastic surges swept over the entire island. During about the next 600 years, lava flows and scoria deposits filled the SE crater, which also collapsed repeatedly. The current Ikenosawa crater was considered by Takada et al. (1992) to have formed by ring collapse at the time of a debris avalanche, after which the volcano was quiescent until the eruptions of historical time.

Myojin Knoll
A large submarine caldera, Myojin Knoll, lies between Aoga-shima and Bayonnaise Rocks volcanoes in the Izu-Bonin arc. The 6-7 km wide caldera, one of nine along this arc, has walls 500-900 m high. The high point on the western caldera rim is a pumice-mantled remnant of the pre-collapse volcanic complex that reaches a depth of 360 m. The walls of the caldera, also known as Kita-Bayonnaise (North Bayonnaise) reveal rhyolitic lava flows, shallow intrusions, and volcaniclastic deposits. A voluminous blanket of coarse rhyolitic pumice from the caldera-forming eruption mantles the caldera rim and its outer flanks. Post-caldera eruptions formed a lava dome that rises 250 m above the caldera floor. The age of the caldera is not known, but was considered by Fiske et al. (2001) to perhaps be as young as a few thousand years. An active hydrothermal vent field lies on the eastern caldera floor and has produced a polymetallic sulfide deposit from vent chimneys up to 30 m high that emit fluids as hot as 278 degrees C.

Bayonnaise Rocks
Bayonnaise Rocks represent part of the barely exposed rim of a largely submarine 8-9 km wide caldera. Formation of the caldera was followed by construction of a large (2.6 cu km) lava dome and/or lava flow complex on the caldera floor, originally located at a depth of 1000-1100 m. Most historical eruptions, recorded since the late-19th century, have occurred from Myojin-sho, a large post-caldera lava dome constructed on the NE rim of the caldera. Deposits from submarine pyroclastic flows associated with growth of the dacitic lava dome mantle the conical dome and extend into the NE part of the caldera and down its outer slopes. An explosive submarine eruption from Myojin-sho in 1952 destroyed a Japanese research vessel, killing all 31 on board. Submarine eruptions have also been observed from other points on the caldera rim and outside of the caldera.

Smith Rock
Smith Rock is a steep-sided basaltic pinnacle that forms part of the outer southern flank of a 8-9 km wide submarine caldera that truncates a 20-km-wide seamount. The caldera was formed between about 60,000 and 30,000 years ago. The Shirane dacitic central cone, 3 km wide and 800 m high, rises to within 8 m of the sea surface in the eastern side of the caldera, whose 600-700 m high walls and outer flanks expose basaltic, andesitic, and rhyolitic rocks. Two large submarine cones, Sumisu Knolls No. 1 and 2, lie west of the caldera. Submarine eruptions have been reported from a number of locations near 136-m-high Smith Rock (also known as Sumisu-jima, or Smith Island), the last of which occurred in 1916. Water discoloration has been frequently observed since the 1970s near Smith Rock. In October 1992, a 6-km-long zone of discolored water was seen extending from the shallow Shirane rock mass near the eastern rim of the caldera, which rises to within 7 m of the sea surface and is the youngest feature of the volcanic complex.

Tori-shima
The circular, 2.7-km-wide island of Tori-shima in the southern Izu Islands is capped by an unvegetated summit cone formed during an eruption in 1939. Fresh lava flows from this eruption form part of the northern coastline of the basaltic-to-dacitic edifice. The volcano is also referred to as Izu-Tori-shima to distinguish it from the several other Japanese island volcanoes called Tori-shima ("Bird Island"). The main cone is truncated by a 1.5-km-wide caldera that contains two central cones, of which 394-m-high Iwo-yama is the highest. Historical eruptions have also occurred from flank vents near the north coast and offshore submarine vents. A 6-8 km wide submarine caldera lies immediately to the north of Tori-shima.

Suiyo Seamount
Suiyo Seamount, one of the Shichiyo Seamounts, named for the 7 days of the week, lies south of Sofugan volcano. Suiyo ("Wednesday") is an basaltic-to-dacitic submarine caldera and lava dome that rises abaout 1400 m from the sea floor to within 1418 m of the sea surface. The summit caldera is 1.5 km wide and about 500 m deep. Major hydrothermal activity was observed in July 1991, with temperatures reaching more the 290 degrees Centigrade, and the volcano was reclassified as active by the Japan Meteorological Agency.

Mokuyo Seamount
Mokuyo Seamount is one of the Shichiyo Seamounts, named for the 7 days of the week. Mokuyo ("Thursday") is a basaltic-andesite submarine caldera that rises 1780 m from the sea floor to within 920 m of the sea surface. The summit caldera is 3 x 2.3 km wide and about 450 m deep and contains a 180-m-high lava dome in its center. Major hydrothermal activity was observed in July 1990, and the volcano was reclassified as active by the Japan Meteorological Agency.

Doyo Seamount
Doyo Seamount is the southernmost of the Shichiyo Seamounts, named for the 7 days of the week. Doyo ("Saturday") is a basaltic-andesite submarine caldera that rises 2340 m from the sea floor to within 860 m of the sea surface. The large horseshoe-shaped summit caldera is 3 x 10 km wide. Major hydrothermal activity was observed in July 1990, and the volcano was reclassified as active by the Japan Meteorological Agency.

Nishino-shima
Volcano Islands (Japan)
The small island of Nishino-shima was recently enlarged when it was joined to several new islands that formed during an eruption in 1973-74. Water discoloration has been observed on several occasions since. The 700-m-wide island is the summit of a massive submarine volcano that has prominent satellitic peaks to the south, west, and NE. The summit of the southern cone rises to within 214 m of the sea surface 9 km SSE of Nishino-shima.

Kaikata Seamount
Volcano Is
Lava dome ?
Kaikata Seamount is a basaltic-to-dacitic submarine volcano located north of Kaitoku Seamount. The volcano rises 2350 m from the sea floor to within 162 m of the sea surface. The seamount contains two major summit peaks oriented NE-SW, with the SW peak being the highest. Hydrothermal activity was observed in 1988 at a depth of 460 m, and the volcano was reclassified as active by the Japan Meteorological Agency.

Kaitoku Seamount
Volcano Is
A submarine eruption was observed in 1984 from the SE peak of Kaitoku Seamount (Kaitoku Kaizan), a three-peaked submarine volcano 130 km NW of Iwo-jima. The SE peak is also known as Higashi-Kaitokuba (East Kaitokuba). A submarine eruption had previously been reported in 1543 from a point near the SW summit, the shallowest of the three, also known as Nishi-Kaitokuba (West Kaitokuba). The Japan Meteorological Agency (1996) listed depths of 103, 353, and 506 m for the SW, SE, and northern summits, respectively. The three volcanoes, whose summits are 13-18 km apart, are the highest features of a massive submarine volcano.

Kita-Iwo-jima
Volcano Islands (Japan)
No historical eruptions have occurred from the deeply eroded Kita-Iwo-jima stratovolcano, which forms a steep-sided basaltic cone rising 792 m above the sea. However, eruptions have been recorded since the 18th century from Funka-Asane, a submarine vent about 2 km NW of the island. Kita-Iwo-jima ("North Sulfur Island") is the northernmost of the Kazan Retto (Volcano Islands), located in the middle of the Izu-Marianas arc.

Ioto [Iwo-jima]
Volcano Islands (Japan)
Tuff cone
Ioto (also known as Iwo-jima) in the central Volcano Islands portion of the Izu-Marianas arc lies within a 9-km-wide submarine caldera. Ioto, Iwo-jima, and Io-jima are among many transliterations of the name, which means "Sulfur Island;" the volcano is also known as Ogasawara Io-jima to distinguish it from several other "Sulfur Island" volcanoes in Japan. The triangular, low-elevation, 8-km-long island narrows toward its SW tip and has produced trachyandesitic and trachytic rocks that are more alkalic than those of other Izu-Marianas arc volcanoes. The island has undergone dramatic uplift for at least the past 700 years accompanying resurgent doming of the caldera. A shoreline landed upon by Captain Cook's surveying crew in 1779 is now 40 m above sea level. The Moto-yama plateau on the NE half of the island consists of submarine tuffs overlain by coral deposits and forms the island's high point. Many fumaroles are oriented along a NE-SW zone cutting through Moto-yama. Numerous historical phreatic eruptions, many from vents on the west and NW sides of the island, have accompanied the remarkable uplift.

Kita-Fukutokutai
Volcano Is
Kita-Fukutokutai is a newly recognized submarine volcano halfway between Iwo-jima and Minami-Iwo-jima islands. The volcano rises to within 73 m of the sea surface. Water discoloration was reported several times beginning in 1937, and floating pumice was seen in 1953-54. In 1988 a fishing boat reported an eruption column about 100 m high, although the report was not confirmed at the time. The Japan Meteorological Agency, which has responsibility for the oversight of Japanese volcanoes, has classified Kita-Fukutokutai as an active volcano.

Fukutoku-Okanoba
Pyroclastic cone
Fukutoku-Okanoba is a submarine volcano located 5 km NE of the pyramidal island of Minami-Iwo-jima. Water discoloration is frequently observed from the volcano, and several ephemeral islands have formed in the 20th century. The first of these formed Shin-Iwo-jima ("New Sulfur Island") in 1904, and the most recent island was formed in 1986. Fukutoku-Okanoba is part of an elongated edifice with two major topographic highs trending NNW-SSE and is a trachyandesitic volcano geochemically similar to Iwo-jima.
Smithsonian Volcano Information | CNMI Emergency Management Office | USGS Volcano Hazards Program

Minami-Hiyoshi
Periodic water discoloration and water-spouting have been reported over this submarine volcano since 1975, when detonations and an explosion were also reported. Minami-Hiyoshi lies near the SE end of a coalescing chain of youthful seamounts and is the only historically active vent. The reported depth of the summit of the trachyandesitic volcano has varied between 274 and 30 m. The morphologically youthful seamounts Kita-Hiyoshi and Naka-Hiyoshi lie to the NW, and Ko-Hiyoshi to the SE.

Nikko
Nikko submarine volcano is a massive seamount that rises from nearly 3 km depth to within 391 m of the sea surface at the SE end of a submarine ridge segment extending from Minami-Iwo-jima island. Two large cones at the basaltic-to-andesitic volcano have been constructed on the NW and NE rims of a roughly 3-km-wide, flat-floored submarine caldera, whose rim is prominently displayed on the southern side, but largely buried on the north. A smaller cones lies on the SE caldera floor. The larger NW cone lies within a partially buried crater and displays hydrothermal activity. Discolored water was observed above Nikko seamount in July 1979, but no water discoloration has been observed during semi-regular seasonal reconnaissance flights since then. Hydrothermal venting was documented during a recent NOAA expedition.

Fukujin
One of the larger of the submarine volcanoes of the Marianas arc, Fukujin seamount has risen on occasion to just beneath the sea surface. Intermittent periods of water discoloration have been observed since the mid-20th century, and eruptions producing floating pumice were noted on several occasions.

Kasuga
Kasuga seamount is a conical volcano that rises to within 598 m of the sea surface SE of Fukujin submarine volcano. Kasuga is listed as an active volcano by the Japan Meteorological Agency, and floating pumice attributed to a submarine eruption of Kasuga was seen south of the volcano in the summer of 1959. Water discoloration from a possible submarine eruption was reported from a location near Kasuga seamount in November 1975. Kasuga, the northernmost of three seamounts in the the Kasuga seamount chain, rises from a depth of 3000 m. A series of flank vents are located low on the southern side of the edifice. The summit of Kasuga does not have a caldera or display hydrothermal activity, and the volcano is largely mantled by volcaniclastics. Altered basaltic and andesitic rocks dredged from the summit suggest that Kasuga 1 is the oldest of the three seamounts, although delicately preserved lava flow lobes and toes from a flank eruption suggest a very youthful age.

Minami Kasuga
Minami Kasuga (South Kasuga) is the central of three NNE-SSW trending volcanoes forming the Kasuga seamount chain, which trends SSE from the volcanic front of the Izu-Marianas arc. Minami Kasuga (also referred to as Kasuga 2) rises from about 3000 m depth to within 170 m of the sea surface and is the highest and largest volume of the three volcanoes. Two subsidiary cones are located low on the eastern flank. The morphology of Minami Kasuga is more complex than Kasuga 1 volcano to the north, and prominent ridges separate slopes of interspersed volcaniclastic and lava flow fields. Radionuclide decay rates indicate an age for Minami Kasuga of less than 8000 years and probably less than 1000 years; radium/thorium disequilibrium ratios suggest the flows may be only a few centuries old (Fryer et al., 1997). Active hydrothermal fields are located at the summit of Minami Kasuga, at the base of summit ridges, and on the lower flanks.

NW Eifuku
NW Eifuku is a small submarine volcano that pales in size in comparison to its larger neighbors, but displays vigorous thermal activity. The summit of the basaltic-to-andesitic Northwest Eifuku volcano lies 1535 m below the sea surface; the seamount lies at the NW end of a chain of submarine volcanoes that includes Eifuku and Daikoko, at the SE end. Hydrothermal fluid emission at NW Eifuku includes liquid carbon dioxide bubbles venting from "white smokers," one of only two places where natural liquid carbon dioxide emission has been observed. The hydrothermal field, named Champagne, was discovered during a 2003 NOAA expedition and lies in the steep headwall of a slope-failure scarp that cuts the summit and SW side of the volcano.
Smithsonian Volcano Information | CNMI Emergency Management Office | USGS Volcano Hazards Program

Daikoku
The conical summit of Daikoku seamount lies along an elongated E-W-trending ridge SE of Eifuku submarine volcano and rises to within 323 m of the sea surface. Daikoku submarine volcano is one of about a dozen displaying hydrothermal activity in the southern part of the Izu-Marianas chain. A steep-walled, 50-m-wide cylindrical crater on the north flank, about 75 m below the summit, is at least 135 m deep and was observed to emit cloudy hydrothermal fluid. During a NOAA expedition in 2006, scientists observed a convecting, black pool of liquid sulfur with a partly solidified, undulating sulfur crust at a depth of 420 m below the summit of Daikoku. Gases, particulate with the appearance of smoke, and liquid sulfur were bubbling up from the back edge of the sulfur pool.
Smithsonian Volcano Information | CNMI Emergency Management Office | USGS Volcano Hazards Program

Farallon de Pajaros
Mariana Is
The small 2-km-wide island of Farallon de Pajaros (also known as Uracas) is the northernmost and most active volcano of the Mariana Islands. Its relatively frequent historical eruptions dating back to the mid-19th century have caused the andesitic volcano to be referred to as the "Lighthouse of the western Pacific." The symmetrical, sparsely vegetated summit is the central cone within a small caldera cutting an older edifice, remnants of which are seen on the SE and southern sides near the coast. Flank fissures have fed lava flows during historical time that form platforms along the coast. Both summit and flank vents have been active at Farallon de Pajaros during historical time. Eruptions have also been observed from nearby submarine vents, and Makhahnas seamount, which rises to within 640 m of the sea surface, lies about 10 km to the SW.

Ahyi
Mariana Islands (Central Pacific)
Ahyi seamount is a large conical submarine volcano that rises to within 137 m of the sea surface about 18 km SE of the island of Farallon de Pajaros (Uracas) in the northern Marianas. Water discoloration has been observed over the submarine volcano, and in 1979 the crew of a fishing boat felt shocks over the summit area of the seamount followed by upwelling of sulfur-bearing water. On April 24-25, 2001 an explosive submarine eruption was detected seismically from a seismic station on Rangiroa Atoll, Tuamotu Archipelago. The event was well constrained (+/- 15 km) at a location near the southern base of Ahyi; the summit of the seamount lies within the location uncertainty.

Supply Reef
Mariana Islands (Central Pacific)
Supply Reef is a conical submarine volcano in the northern Mariana Islands that rises to within 8 m of the sea surface. The andesitic seamount lies about 10 km NW of the Maug Islands, the emergent summit of a submarine volcano that is joined to Supply Reef by a low saddle at a depth of about 1800 m. Supply Reef was mapped as Quaternary; living corals on the crater rim suggest that the volcano is either dormant or extinct (Corwin, 1971). Several submarine eruptions have been detected by sonar signals originating from points very approximately located at distances of 15-25 km NW of Supply Reef.

Maug Islands
Mariana Islands (Central Pacific)
Three small elongated islands up to 2.3 km long mark the northern, western, and eastern rims of a largely submerged 2.5-km-wide caldera. The highest point of the Maug Islands reach only 227 m above sea level; the submerged southern notch on the caldera rim lies about 140 m below sea level. The caldera has an average submarine depth of about 200 m and contains a twin-peaked central lava dome that rises to within about 20 m of the sea surface. The Maug Islands form a twin volcanic massif with Supply Reef, about 11 km to the north. The truncated inner walls of the caldera on all three islands expose lava flows and pyroclastic deposits that are cut by radial dikes; bedded ash deposits overlie the outer flanks of the islands. No eruptions are known since the discovery of the islands by Espinosa in 1522. The presence of poorly developed coral reefs and coral on the central lava dome suggests a long period of general quiescence, although it does not exclude mild eruptions (Corwin, 1971). A recent NOAA expedition detected possible evidence of submarine geothermal activity.

Asuncion
A single large asymmetrical stratovolcano, steeper on the NE side, forms 3-km-wide Asuncion Island. The steep NE flank of the 857-m-high volcano terminates in high sea cliffs. The gentler SW flanks have low-angle slopes bounded by sea cliffs only a few meters high. The southern flank of the volcano is cut by a large landslide scar. The southern flanks and western flanks of the volcano are mantled by ash deposits that may have originated during eruptions in historical time. An explosive eruption in 1906 also produced lava flows that descended about half way down the western and SE flanks, but several other historical eruption reports are of uncertain validity.

Agrigan
The highest of the Marianas arc volcanoes, Agrigan contains a 500-m-deep, flat-floored caldera. The elliptical island is 8 km long; its 965-m-high summit is the top of a massive 4000-m-high submarine volcano, the second largest in the Marianas Islands. Deep radial valley dissect the flanks of the thickly vegetated stratovolcano. The elongated caldera is 1 x 2 km wide and is breached to the NW, from where a prominent lava flow extends to the coast and forms a lava delta. The caldera floor is surfaced by fresh-looking lava flows and also contains two cones that may have formed during the volcano's only historical eruption in 1917. This eruption deposited large blocks and 3 m of ash and lapilli on a village on the SE coast, prompting its evacuation.

Pagan
Maars
Pagan Island, the largest and one of the most active of the Mariana Islands volcanoes, consists of two stratovolcanoes connected by a narrow isthmus. Both North and South Pagan stratovolcanoes were constructed within calderas, 7 and 4 km in diameter, respectively. The 570-m-high Mount Pagan at the NE end of the island rises above the flat floor of the northern caldera, which probably formed during the early Holocene. South Pagan is a 548-m-high stratovolcano with an elongated summit containing four distinct craters. Almost all of the historical eruptions of Pagan, which date back to the 17th century, have originated from North Pagan volcano. The largest eruption of Pagan during historical time took place in 1981 and prompted the evacuation of the sparsely populated island.

Alamagan
Alamagan is the emergent summit of a large stratovolcano in the central Mariana Islands with a roughly 350-m-deep summit crater east of the center of the island. The exposed cone is largely Holocene in age. A 1.6 x 1 km graben cuts the SW flank. An extensive basaltic-andesite lava flow has extended the northern coast of the island, and a lava platform also occurs on the south flank. Pyroclastic-flow deposits erupted about 1000 years ago have been dated, but reports of historical eruptions were considered invalid (Moore and Trusdell, 1993).

Guguan
The small island of Guguan, only 2.8 km wide, is composed of an eroded volcano on the south, a caldera with a post-caldera cone, and a northern volcano. The latter has three coalescing cones and a breached summit crater that fed lava flows to the west and NW. The 287-m high point of the island is the south rim of the caldera. Freycinet misidentifed Guguan with Alamagan; reported eruptions in 1819 and 1901 (Catalog of Active Volcanoes of the World) actually refer to solfataric activity on Alamagan (Corwin, 1971). The only known historical eruption of Guguan took place between 1882 and 1884 and produced the northern volcano and lava flows that reached the coast.

Zealandia Bank
Mariana Is
Zealandia Bank consists of two pinnacles about 1 km apart rising from a submerged bank to near the sea surface between Guguan and Sarigan Islands. One pinnacle reaches >1 m above water at low tide. Andesitic rocks were dredged at the southern peak, which showed some evidence of coral growth. Freshly broken pahoehoe basaltic rocks were recovered on the western flank of Zealandia Bank. The age of the most recent eruptive activity at Zealandia Bank is not known, but a NOAA bathymetric survey in 2004 detected fumarolic activity.

Sarigan
Sarigan volcano forms a 3-km-long, roughly triangular island. A low truncated cone with a 750-m-wide summit crater contains a small ash cone. The youngest eruptions produced two lava domes from vents above and near the south crater rim. Lava flows from each dome reached the coast and extended out to sea, forming irregular shorelines. The northern flow overtopped the crater rim on the north and NW sides. The sparse vegetation on the flows indicates they are of Holocene age (Meijer and Reagan, 1981).

Anatahan
The elongate, 9-km-long island of Anatahan in the central Mariana Islands consists of a large stratovolcano with a 2.3 x 5 km, E-W-trending compound summit caldera. The larger western portion of the caldera is 2.3 x 3 km wide, and its western rim forms the island's 790-m high point. Ponded lava flows overlain by pyroclastic deposits fill the floor of the western caldera, whose SW side is cut by a fresh-looking smaller crater. The 2-km-wide eastern portion of the caldera contained a steep-walled inner crater whose floor prior to the 2003 eruption was only 68 m above sea level. A submarine volcano, NE Anatahan, rises to within 460 m of the sea surface on the NE flank of the volcano, and numerous other submarine vents are found on the NE-to-SE flanks. Sparseness of vegetation on the most recent lava flows on Anatahan had indicated that they were of Holocene age, but the first historical eruption of Anatahan did not occur until May 2003, when a large explosive eruption took place forming a new crater inside the eastern caldera.

East Diamante
Mariana Is
The dacitic East Diamante submarine volcano contains an elongated NE-SW-trending caldera with a pronounced rim on the NE side. A large post-caldera cone lies on the SW caldera rim, and a complex of lava domes was constructed in the center of the caldera. Several areas of hydrothermal activity including "black smoker" sulfide chimneys at the Black Forest site were detected on the central dome complex at depths of only a few hundred meters. These marked the shallowest black smokers yet discovered. The summit of the submarine volcano extends to within 127 m of the sea surface.

Ruby
Ruby, a basaltic submarine volcano that rises to within 230 m of the sea surface near the southern end of the Mariana arc NW of Saipan, was detected in eruption in 1966 by sonar signals (Norris and Johnson, 1969). In 1995 submarine explosions were heard, accompanied by a fish kill, sulfurous odors, bubbling water, and the detection of volcanic tremor.

Esmeralda Bank
Esmeralda Bank is a massive submarine volcano with three summit cones oriented along a N-S line. Their summits are from 43 to 140 m beneath the sea surface. The highest, middle peak contains a 3-km-wide caldera open to the west and several parasitic cones. Frequent sulfur boils and water discoloration have been observed, which have variously been attributed to eruptive events or solfataric activity.

NW Rota-1
A submarine volcano detected during a 2003 NOAA bathymetric survey of the Mariana Island arc was found to be hydrothermally active and named NW Rota-1. The basaltic to basaltic-andesite seamount rises to within 517 m of the sea surface SW of Esmeralda Bank and lies 64 km NW of Rota Island and about 100 km north of Guam. When Northwest Rota-1 was revisited in 2004, a minor submarine eruption from a vent named Brimstone Pit on the upper south flank about 40 m below the summit intermittently ejected a plume several hundred meters high containing ash, rock particles, and molten sulfur droplets that adhered to the surface of the remotely operated submersible vehicle. The active vent was funnel-shaped, about 20 m wide and 12 m deep. NW Rota-1 is large submarine volcano with prominent structural lineaments about a kilometer apart cutting across the summit of the edifice and down the NE and SW flanks.
Smithsonian Volcano Information | NOAA Pacific Marine Environmental Laboratory | USGS Volcano Hazards Program

Forecast Seamount
Forecast Seamount lies about 70 km west of the southern tip of Guam and about 19 km NW of Seamount X. Hydrothermal fluid temperatures up to 200 degrees C, one of the highest temperature vent systems known in the Mariana arc, were measured during a 2006 NOAA expedition. Vent community species that occur on Forecast Seamount include shrimp, snails, limpets, crabs, sulfide worms, and scale worms, and differ from those further to the north in the Marianas arc.
Smithsonian Volcano Information | NOAA Pacific Marine Environmental Laboratory | USGS Volcano Hazards Program

Seamount X
Hydrothermal activity was detected during a 2003 NOAA expedition at a submarine volcano about 70 km WSW of Guam. The summit of the volcano, referred to as Seamount X, lies 1230 m below the sea surface. Diffuse sites of thermal venting colonized by shrimps, crabs, and scaleworms were detected near the summit during a 2006 NOAA expedition, and thick deposits of sulfur flows originating from the hydrothermal vent were observed that were covered with thousands of squat lobsters. Basaltic rocks were recovered along with sulfur samples. The summit of the volcano is cut by an elongated caldera.
Smithsonian Volcano Information | NOAA Pacific Marine Environmental Laboratory | USGS Volcano Hazards Program

Hokkaido

Oshima-Oshima
Hokkaido
Oshima-Oshima, a small, 4-km-wide Japan Sea island 55 km west of the SW tip of Hokkaido, is the emergent summit of two coalescing basaltic-to-andesitic stratovolcanoes. Higashi-yama, at the east end of the island, is cut by a 2-km-wide caldera covered on its west side by Nishi-yama volcano. The western cone failed during an eruption in 1741, creating a large horseshoe-shaped caldera breached to the north that extends from the summit down to the sea floor at the base of the volcano and producing a mostly submarine debris avalanche that traveled 16 km. A tsunami associated with the collapse swept the coasts of Hokkaido, western Honshu, and Korea, and caused nearly 1500 fatalities. The 1741 eruption, the largest in historical time at Oshima-Oshima, concluded with the construction of a basaltic pyroclastic cone at the head of the breached caldera. No eruptions have occurred since the late-18th century.

E-san
Hokkaido
E-san, a small andesitic stratovolcano capped by a 618-m-high lava dome, is Hokkaido's southernmost active volcano. E-san occupies the eastern tip of the double-pronged Oshima Peninsula across the Tsugaru Strait from Honshu. Another lava dome is located to the NW. Both the E-san lava dome, which formed about 9000 years ago, and the NW dome have been active during the Holocene. A minor phreatic eruption in 1846 produced a mudflow that caused many fatalities. The latest activity at E-san was a small eruption in 1874. Active fumaroles occur at a thermal area on the upper NW flank.

Komaga-take
The truncated Komaga-take volcano on the Oshima Peninsula of southern Hokkaido is one of the most active volcanoes of Japan's northernmost island. Komaga-take's sharp-topped 1131-m-high summit lies at the western side of a large breached crater that formed as a result of edifice collapse in 1640 AD. Hummocky debris avalanche material occurs at the base of the volcano on three sides. Much of the andesitic Komaga-take volcano is Pleistocene in age. Two late-Pleistocene and two Holocene plinian eruptions occurred prior to the first historical eruption in 1640, which began a period of more frequent explosive activity. The 1640 eruption, one of the largest in Japan during historical time, deposited ash as far away as central Honshu and produced a debris avalanche that reached the sea. The resulting tsunami caused 700 fatalities. Three plinian eruptions have occurred since 1640; in 1694, 1856, and 1929.

Nigorigawa
Hokkaido (Japan)
Hydrothermal field
Nigorigawa geothermal field is located in the late-Pleistocene Nigorikawa caldera in SW Hokkaido. The small 3-km-wide caldera, located along the shores of Uchiura Bay WNW of Komaga-take volcano, was formed during a major explosive eruption about 12,000 years ago. The caldera-forming eruption included the emplacement of pyroclastic-fall and -surge deposits and pyroclastic-flow deposits that extend northward and westward to the Pacific coast. The flat-bottomed caldera floor is cris-crossed by roads and houses of the town of Nigorigawa, and a river of the same name drains the caldera to the NW through a notch in the caldera rim.

Usu
Usu, one of Hokkaido's most well-known volcanoes, is a small stratovolcano located astride the southern topographic rim of the 110,000-year-old Toya caldera. The center of the 10-km-wide, lake-filled caldera contains Naka-jima, a group of forested andesitic lava domes. The summit of the basaltic-to-andesitic edifice of Usu is cut by a somma formed about 7-8,000 years ago when collapse of the volcano produced a debris avalanche that reached the sea. Dacitic domes erupted along two NW-SE-trending lines fill and flank the summit caldera. Three of these domes, O-Usu, Ko-Usu and Showa-Shinzan, along with seven crypto-domes, were erupted during historical time. The 1663 eruption of Usu was one of the largest in Hokkaido during historical time. The war-time growth of Showa-Shinzan from 1943-45 was painstakingly documented by the local postmaster, who created the first detailed record of growth of a lava dome.

Niseko
The Niseko volcano group in SW Hokkaido, WNW of Yotei volcano, contains a cluster of andesitic stratovolcanoes and lava domes. The volcanic complex is located NW of Niseko City. The latest dated activity at the Niseko group was a phreatic to magmatic eruption about 7000 years ago. Fumarolic areas and hot springs are found at various locations in the Niseko volcano group.

Yotei
Yotei is a symmetrical andesitic-to-dacitic stratovolcano with a Fuji-like profile located NW of Toya caldera. Its summit is truncated by a 700-m-wide crater that is cut on its NW rim by overlapping smaller craters. Deep radial gullies cut the flanks of Yotei. The latest eruption from Yotei took place about 5000-6000 years ago.

Shiribetsu
Shiribetsu volcano, located immediately SE of Yotei volcano in southwestern Hokkaido, is a small, 1107-m-high andesitic stratovolcano that contains a 1.5-km-wide crater breached widely to the west. It was created by a massive debris avalanche that removed the summit and swept more than 7 km to the west, forming a hummocky deposit at the SE foot of Yotei volcano. Shiribetsu volcano was mapped as Holocene in age (Japan Association of Quaternary Research, 1987).

Kuttara
The Kuttara volcanic group consists of a series of small stratovolcanoes, lava domes, pyroclastic cones, and a caldera near the Pacific coast SE of Toya caldera and SW of Shikotsu caldera. The Kuttara group was constructed during five major eruptive stages, the first of which occurred more than 60,000 years ago. A major dacitic pumice eruption at the end of the 4th stage about 40,000 years ago resulted in the formation of the 3-km-diameter Kuttara caldera. The caldera cut a basaltic-to-andesitic stratovolcano complex, which late in its activity produced two major andesitic lava flows on its north side at Kita-yama. Explosions, probably in early Holocene time, formed two large craters on the west flank of the caldera, and a dacitic lava dome was emplaced about 10,000 years ago. Late-stage phreatic explosion products from Jigoku-dani, a 300-400 m wide crater south of the lava dome, overlie the 1663 tephra from Usu volcano. Jigoku-dani and Noboribetsu Spa are the sites of intense thermal activity, including fumaroles, hot springs, and geysers.

Shikotsu
The 13 x 15 km Shikotsu caldera, largely filled by the waters of Lake Shikotsu, was formed during one of Hokkaido's largest Quaternary eruptions about 31-34,000 years ago. The small andesitic Tarumai stratovolcano was then constructed on its SE rim and has been Hokkaido's most active volcano in historical time. Pyroclastic-flow deposits from Tarumai extend nearly to the Pacific coast. Two other Holocene post-caldera volcanoes, Fuppushi (adjacent to Tarumai) and Eniwa (on the opposite side of the caldera), occur on a line trending NW from Tarumai, and were constructed just inside the caldera rim. Minor eruptions took place from the summit of Eniwa volcano as late as the 17th century. The summit of Tarumai contains a small 1.5-km-wide caldera formed during two of Hokkaido's largest historical eruptions, in 1667 and 1739. Tarumai is now capped by a flat-topped summit lava dome that formed in 1909.

Rishiri
Rishiri is a highly dissected andesitic stratovolcano that forms a 20-km-wide island west of the northern tip of Hokkaido. Extensive erosion has produced an extremely rugged topography, with a dramatic sharp-topped, 1719-m-high summit flanked by steep-sided radial ridges. A stratovolcano and flank lava domes were constructed at Rishiri beginning less than 200,000 years ago. Eruptions at the stratovolcano ceased about 37,000 years ago, after which only flank vents were active. Late-stage eruptions took place from scoria cones and maars along a 15-km-long NW-SE trend that extends to the SE coast. Flank eruptions were dominantly basaltic, but also included andesitic and rhyolitic activity. Extensive late-stage lava flows during the late Pleistocene form much of the northern and western coasts and extend offshore. The latest eruptions at Rishiri took place a few thousand years ago.

Tokachi
Tokachi volcano consists of a group of dominantly andesitic stratovolcanoes and lava domes arranged on a NE-SW line above a plateau of welded Pleistocene tuffs in central Hokkaido. Numerous explosion craters and cinder cones are located on the upper flanks of the small stratovolcanoes, with the youngest Holocene centers located at the NW end of the chain. Frequent historical eruptions, consisting mostly of mild-to-moderate phreatic explosions, have been recorded since the mid-19th century. Two larger eruptions occurred in 1926 and 1962. Partial cone collapse of the western flank of Tokachi-dake during the 1926 eruption produced a disastrous debris avalanche and mudflow.

Daisetsu
The Daisetsu volcano group (also spelled Taisetsu) lies at the northern end of the Daisetsu-Tokachi graben in central Hokkaido. It consists of a complex group of stratovolcanoes and lava domes associated with a small, 2-km-wide caldera. The eight satellitic volcanoes are aligned along a ring fracture that is centered over the eastern rim of the caldera. Asahi-dake, the highest peak of the complex, was constructed 3 km SW of the center of the caldera. Other stratovolcanoes are located along a NE-SW line cutting through the caldera that trends toward the Tokachi volcano complex to the SW. In contrast to the Tokachi group, no historical eruptions are known from Daisetsu, although the latest phreatic eruption took place sometime after 1739 AD. Fumarolic areas are located on Asahi-dake, where at one time sulfur was mined, and in the caldera.

Nipesotsu-Maruyama
The Nipesotsu-Maruyama volcano group, located west of Nukabira lake about 20 km east of Tokachi-dake volcano, is composed of a number of overlapping andesitic-to-dacitic stratovolcanoes and lava domes constructed along a NW-SE trend. The highest peak in the complex is 2013-m-high Nipesotsu-yama stratovolcano, which was active during the mid-Pleistocene, about 0.4-0.2 million years ago. The Maruyama stratovolcano and lava dome at the southern end of the complex was discovered to be a Quaternary volcano only in 1989. It is also referred to as Higashi-Tokachi-Maruyama to distinguish it from several other volcanoes named Maru-yama, which means "Round Mountain." A minor phreatic eruption took place at Maru-yama lava dome in 1898, and fumaroles are present on one of its summit craters.

Shikaribetsu Group
Shikaribetsu volcano consists of a group of andesitic-to-dacitic lava domes west and south of Lake Shikaribetsu in central Hokkaido. The youngest domes, which were mapped as Holocene (Japan Association of Quaternary Research, 1987), were constructed along a ENE-WSW line south of the lake. The age of the latest eruptions is not known precisely, but is less than 20,000 years (Nakano et al., 2001-). The largest dome, Higashi-Nupukaushinupuri, was built at the SW, breached end of a horseshoe-shaped crater. Two or more large debris-avalanche deposits extend to the south.

Akan
Akan is a 13 x 24 km, elongated caldera that formed more than 31,500 years ago immediately SW of Kutcharo caldera. Growth of four post-caldera stratovolcanoes, three at the SW end of the caldera and the other at the NE side, has restricted the size of the caldera lake. The 1-km-wide Nakamachineshiri crater was formed during a major pumice-and-scoria eruption about 13,500 years ago. Of the Holocene volcanoes of the Akan volcanic complex, only the Me-Akan group, east of Lake Akan, has been historically active, producing mild phreatic eruptions since the beginning of the 19th century. Me-Akan is composed of 9 overlapping cones. The main cone of Me-Akan proper has a triple crater at its summit. Historical eruptions at Me-Akan have consisted of minor phreatic explosions, but four major magmatic eruptions including pyroclastic flows have occurred during the Holocene.

Kutcharo
The 20 x 26 km Kutcharo caldera (also spelled Kussharo or Kuccharo), is the largest of a cluster of calderas in NE Hokkaido. The caldera was formed in a series of major eruptions between about 340,000 and 30,000 years ago. Naka-jima, a Holocene post-caldera dacitic-to-rhyolitic lava-dome complex, forms an island in the large lake that fills much of the western half of the caldera. The Holocene Atosanupuri stratovolcano and lava-dome complex islocated near the center of the caldera, east of the crescent-shaped Lake Kutcharo. Many lava domes were formed at Atosanupuri between about 10,000 and 1000 years ago. No historical eruptions are known, although intense fumarolic activity occurs on and around Atosanupuri volcano and along the shores of Lake Kutcharo.

Mashu
Mashu is a 6-km-wide Holocene caldera that truncates a stratovolcano constructed on the ESE rim of the large Kutcharo caldera. The steep-walled caldera, filled by the remarkably transparent waters of Lake Mashu, is one of the scenic highlights of Hokkaido. Following caldera collapse, a small andesitic stratovolcano, Kamuinupuri, was formed beginning about 4000 years ago, creating a reentrant into the SE side of the deep caldera lake. A large explosive eruption about 1000 years ago, the latest dated eruption from Mashu volcano, created a 1.2 x 1.5 km crater at the summit of Kamuinupuri. The small island of Kamuishu in the center of Lake Mashu represents the tip of a mostly submerged dacitic lava dome.

Rausu
Rausu is an andesitic-to-dacitic stratovolcano with summit lava domes on the Shiretoko Peninsula in NE Hokkaido. The 1660-m-high volcano is located along a ridge 5 km SW of Shiretoko-Iwo-san volcano, the NE-most Holocene volcano in Hokkaido. Young lava flows descent the NW flank and broad areas along the SE flank of Rausu, and an older lava flow traveled about 9 km to the west, reaching the coast of the Sea of Okhotsk along a broad front. Rausu-dake volcano produced eruptions of pumiceous tephras with associated pyroclastic flows about 2200, 1400, and 800 years ago. Recent work has documented a pyroclastic-flow deposit that overlies the 1739 tephra from Tarumai volcano in SW Hokkaido. Stratigraphic relationships place this eruption, the most recent known from Rausu, between about 1750 and 1850 AD.

Shiretoko-Iwo-zan
Shiretoko-Iwo-zan, one of many Japanese "sulfur mountains," is noted for the extrusion of molten sulfur during eruptions in 1889 and 1936. Located at the NE tip of Hokkaido on the Shiretoko Peninsula, the andesitic volcano contains two large craters at the summit that are breached to the NW. The southern crater contains a small flat-topped lava dome. The main cone, Naka-dake, was constructed NW of the headwalls of the two breached craters. Historical eruptions have originated from the southernmost of three explosion craters along a NNE-SSW line on the NW flank of the main cone of Shiretoko-Iwo-san.

Loihi 0 MA
Loihi
Hawaii (USA)
Lava cones
Longitude: 155.27°W
Loihi seamount, the youngest volcano of the Hawaiian chain, lies about 35 km off the SE coast of the island of Hawaii. Loihi (which is the Hawaiian word for "long") has an elongated morphology dominated by two curving rift zones extending north and south of the summit. The summit region contains a caldera about 3 x 4 km wide and is dotted with numerous lava cones, the highest of which is about 975 m below the sea surface. The summit platform includes two well-defined pit craters, sediment-free glassy lava, and low-temperature hydrothermal venting. An arcuate chain of small cones on the western edge of the summit extends north and south of the pit craters and merges into the crests of Loihi's prominent rift zones. Deep and shallow seismicity indicate a magmatic plumbing system distinct from that of Kilauea volcano. During 1996, a new pit crater was formed at the summit of the volcano, and lava flows were erupted. Continued volcanism is expected to eventually build a new island at Loihi; time estimates for the summit to reach the sea surface range from roughly 10,000 to 100,000 years.
Smithsonian Volcano Information | Hawaiian Volcano Observatory | USGS Volcano Hazards Program

Kilauea - 0,004 Ma
Kilauea
Hawaii (USA)
Longitude: 155.287°W
Kilauea volcano, which overlaps the east flank of the massive Mauna Loa shield volcano, has been Hawaii's most active volcano during historical time. Eruptions of Kilauea are prominent in Polynesian legends; written documentation extending back to only 1820 records frequent summit and flank lava flow eruptions that were interspersed with periods of long-term lava lake activity that lasted until 1924 at Halemaumau crater, within the summit caldera. The 3 x 5 km caldera was formed in several stages about 1500 years ago and during the 18th century; eruptions have also originated from the lengthy East and SW rift zones, which extend to the sea on both sides of the volcano. About 90% of the surface of the basaltic shield volcano is formed of lava flows less than about 1100 years old; 70% of the volcano's surface is younger than 600 years. A long-term eruption from the East rift zone that began in 1983 has produced lava flows covering more than 100 sq km, destroying nearly 200 houses and adding new coastline to the island.
Smithsonian Volcano Information | Hawaiian Volcano Observatory | USGS Volcano Hazards Program

Mauna Loa 0,01 Ma
Mauna Loa
Hawaii (USA)
Longitude: 155.608°W
Massive Mauna Loa shield volcano rises almost 9 km above the sea floor to form the world's largest active volcano. Flank eruptions are predominately from the lengthy NE and SW rift zones, and the summit is cut by the Mokuaweoweo caldera, which sits within an older and larger 6 x 8 km caldera. Two of the youngest large debris avalanches documented in Hawaii traveled nearly 100 km from Mauna Loa; the second of the Alika avalanches was emplaced about 105,000 years ago (Moore et al. 1989). Almost 90% of the surface of the basaltic shield volcano is covered by lavas less than 4000 years old (Lockwood and Lipman, 1987). During a 750-year eruptive period beginning about 1500 years ago, a series of voluminous overflows from a summit lava lake covered about one fourth of the volcano's surface. The ensuing 750-year period, from shortly after the formation of Mokuaweoweo caldera until the present, saw an additional quarter of the volcano covered with lava flows predominately from summit and NW rift zone vents.
Smithsonian Volcano Information | Hawaiian Volcano Observatory | USGS Volcano Hazards Program

Hualalai 0.15 Ma
Hualalai
Hualalai volcano, at the western end of the island, is the third youngest shield volcano on Hawaii. At 2523 m, it is dwarfed by its massive neighbors, Mauna Loa and Mauna Kea. Three rift zones, dotted with cinder cones and spatter cones, trend north, NW, and SE, and converge about 5 km east of the summit. Detailed mapping has shown that 95% of the surface area of the basaltic shield volcano is of Holocene age, more than half is less than 3000 years old, and a quarter is less than 1000 years old. The only historical eruptions of Hualalai took place during the end of the 18th century and in 1801, when lava flows from vents on the NW rift zone reached the sea and buried Hawaiian villages; the 1801 Huehue lava flow underlies part of the international airport at Kona. The earlier of the two flows, the Kaupulehu lava flow, is notable for its large quantities of lava-encrusted mafic and ultramafic nodular xenoliths.

Mauna Kea 0.375 Ma
Mauna Kea
Mauna Kea, Hawaii's highest volcano, reaches 4205 m, only 35 m above its neighbor, Mauna Loa. In contrast to Mauna Loa, Mauna Kea lacks a summit caldera and is capped by a profusion of cinder cones and pyroclastic deposits. Mauna Kea's rift zones are less pronounced than on neighboring volcanoes, and the eruption of voluminous, late-stage pyroclastic material has buried much of the early basaltic shield volcano, giving the volcano a steeper and more irregular profile. This transition took place about 250,000 to 200,000 years ago, and much of Mauna Kea, whose Hawaiian name means "White Mountain," was constructed during the Pleistocene. Its age and high altitude make it the only Hawaiian volcano with glacial moraines. A road that reaches a cluster of astronomical observatories on the summit also provides access to seasonal tropical skiing. The latest eruptions at Mauna Kea produced a series of cinder cones and lava flows from vents on the northern and southern flanks during the early to mid Holocene.

Koala - 0.43 Ma

Haleakala 0.75 Ma
Haleakala
The massive Haleakala shield volcano forms the eastern portion of the dumbbell-shaped island of Maui. The summit of 3055-m Haleakala contains a dramatic, 3.5 x 9.5 km summit crater that is widely breached on the north and SE sides. The "crater" is not of volcanic origin, but formed as a result of the coalescence of headward erosion of the Koolau and Kaupo valleys. Subsequently the crater has been partially filled by a chain of young cinder cones and lava flows erupted along a major rift zone that extends across the basaltic shield volcano from the SW to the east flanks. Another less prominent rift zone trends north from the summit. The most recent eruption of Haleakala was thought to have occurred between the exploring voyages of La Perouse in 1786 and Vancouver in 1793, but uncertainty surrounds the date of this event, which could have occurred in about 1750 AD (anthropological evidence) or several centuries earlier (radiocarbon dates).

Unnamed 9,6 Ma
A "smoke" column rising several thousand meters from the sea, steaming turbulent water, water discoloration, and a probable raft of floating pumice were seen from the air at a point 90 km NE of Necker Island on August 20, 1953. Despite a water depth at this point of approximately 4 km, Macdonald (1959) considered there to be little doubt that a submarine eruption, the westernmost historical volcanic eruption in the Hawaiian lsland chain, had occurred.

Kahoolawe - 1.03 Ma

Lanai - 1.28 Ma

WEST MAUI - 1.32 Ma

Molokai - 1.9 Ma

Koolau - 2.6

Walanoe - 3,6 Ma

Niihau - 4.89 Ma

Kawaikini - 5,6 Ma

Midway - 27.7 Ma

Légende volcans
Attention: - Ma signifie millions d'années (=âge des volcans)

Des indices :
Indice 1:
Chercher ce qu'est un point chaud.
Indice 2:
Sur une carte situer les différents volcans et le point chaud.
Indice 3:
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Le point chaud d'Hawaî
Repère à quel type de volcans correspond le point chaud

Des données

Plaque Pacifique

Plaques tectoniques
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.L'histoire de la tectonique des plaques.

Noms des plaques

Plaque africaine

Plaque Antarctique

Plaque Arabique

Plaque Australienne

Burma Plate

Plaque Caraîbes

Plaque Cocos

Plaque Eurasienne

Plaque Indienne

Paque Juan de Fuca

Plaque Nord Americaine

Plaque de Nazca

Plaque d'Okhotsk

Plaque des Philippine

Paque Rivera

Plaque Scotia

Plaque Sud Américaine

limites des plaques
Tectonic Plate Boundaries, detailed (US Geological Survey). from

Continental Rift Boundary

Oceanic Spreading Rift

Continental Transform Fault

Oceanic Transform Fault

Continental Convergent Boundary

Oceanic Convergent Boundary

Subduction Zone

Plate Convergence

Convergence Arrows

39 mm/yr
Convergence data are shown by arrows describing direction and speed, relative to the plate across the boundary.
For more information, see This Dynamic Planet.

58 mm/yr
Convergence data are shown by arrows describing direction and speed, relative to the plate across the boundary.
For more information, see This Dynamic Planet.

73 mm/yr
Convergence data are shown by arrows describing direction and speed, relative to the plate across the boundary.
For more information, see This Dynamic Planet.

Quelques autres points chauds :

La réunion

Hawaï

Mehetia (Polynésie française)

Islande

animation point chaud
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Cratère Halema`uma`u
Regarder l'heure à Hawaii, penser au décalage horaire. "Accéder à la webcam - Hawaiian Volcano Observatory - USGS"

Mon bilan
Tu peux rédiger ton bilan sur un fichier que tu enregistreras dans le dossier désigné par le professeur
- clique droit sur bilan puis: Ajouter Dossier
Le dossier s'ouvre
-dans Nom: donne un titre
-puis rédige un bilan répondant à la tâche à accomplir

Lexique
Arc insulaire : - ensemble d'îles (souvent volcaniques), réparties en un ou plusieurs alignements courbes dessinant des arcs.
Cône volcanique : : relief formé par l'accumulation des matériaux émis par le volcan.
Cratère: cavité située au sommet du cône volcanique.
Fosse océanique Dépression allongée de grande profondeur (5000 à 10000 m).
Frontière convergente : zone à la limite de 2 plaques qui se rapprochent.
Frontière divergente : zone à la limite de 2 plaques qui s'éloignent.
Lave : magma dégazé émis à la surface du globe terrestre.
Lithosphère: couche superficielle du globe terrestre très rigide: son épaisseur varie selon les endroits de 70km à 150 km (environ).
Magma : matière minérale provenant de la fusion plus ou moins partielle des roches composé de liquides, éléments solides et gaz dissous.
Plaque lithosphérique: vaste zone de la surface du globe constituée de lithosphère et délimitée par des zones ("frontières") actives.
Point chaud : zone très profonde de température élévée permettant la fusion des roches, de cette zone, le magma moins dense remonte en surface.
Un point chaud est considéré comme fixe.
Roches volcaniques : roches issues du refroidissement d'une lave.
Zone active: zone étroite de forte activité sismique et volcanique .

Un calcul pour aller plus loin
A partir des distances séparant les volcans et connaissant leur âge, que peut -on calculer?
Indice : Un pièton marche à une vitesse moyenne de 4km par heure!
Aide : utiliser le fichier "mesurer des distances":

Mesurer des distances
Utiliser l'icône règle de la barre de menu en haut.
Choisir "Trajet"/km puis à vous de continuer ...
Aide: on peut mesurer la distance entre Loihi (volcan actuel donc 0 million d'années) et Kawaïkini (5,6 millions d'années)