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SI/USGS Weekly Volcanic Activity Report 24-30 November 2010
From: "Kuhn, Sally" <KUHNS@xxxxxx>
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SI/USGS Weekly Volcanic Activity Report
24-30 November 2010
Sally Kuhn Sennert - Weekly Report Editor
kuhns@xxxxxx
URL: http://www.volcano.si.edu/reports/usgs/
New Activity/Unrest: | Bulusan, Luzon | Erta Ale, Ethiopia | Kizimen, Eastern Kamchatka (Russia) | Kliuchevskoi, Central Kamchatka (Russia) | Merapi, Central Java (Indonesia) | Tengger Caldera, Eastern Java (Indonesia) | Tungurahua, Ecuador | Ulawun, New Britain
Ongoing Activity: | Dukono, Halmahera | Karymsky, Eastern Kamchatka (Russia) | Katmai, Alaska Peninsula | Kilauea, Hawaii (USA) | Manam, Northeast of New Guinea (SW Pacific) | Sakura-jima, Kyushu | Sarychev Peak, Matua Island | Shiveluch, Central Kamchatka (Russia) | Suwanose-jima, Ryukyu Islands (Japan)
The Weekly Volcanic Activity Report is a cooperative project between the Smithsonian's Global Volcanism Program and the US Geological Survey's Volcano Hazards Program. Updated by 2300 UTC every Wednesday, notices of volcanic activity posted on these pages are preliminary and subject to change as events are studied in more detail. This is not a comprehensive list of all of Earth's volcanoes erupting during the week, but rather a summary of activity at volcanoes that meet criteria discussed in detail in the "Criteria and Disclaimers" section. Carefully reviewed, detailed reports on various volcanoes are published monthly in the Bulletin of the Global Volcanism Network.
Note: Many news agencies do not archive the articles they post on the Internet, and therefore the links to some sources may not be active. To obtain information about the cited articles that are no longer available on the Internet contact the source.
New Activity/Unrest
BULUSAN Luzon 12.770°N, 124.05°E; summit elev. 1565 m
On 24 November, PHIVOLCS reported that an explosion from Bulusan, recorded for almost six minutes by seismographs, produced an ash plume that rose 1 km above the crater, drifted SW, and dissipated. Ashfall was not observed outside of the permanent danger zone, defined as a 4-km radius from the summit, suggesting that ashfall was confined to the upper flanks. On 26 November steam was emitted from known thermal vents and the crater. A steam plume rose 150 m above the NW vent and drifted SW. Later that night an explosion-type earthquake was recorded by the seismic network; cloud cover prevented visual observations of the crater. On 28 November steam rose from the SE and SW vents. During 29 November-1 December steam rose from both the NW vents and thermal vents.
Geologic Summary. Luzon's southernmost volcano, Bulusan, was constructed within the 11-km-diameter dacitic Irosin caldera, which was formed more than 36,000 years ago. A broad, flat moat is located below the prominent SW caldera rim; the NE rim is buried by the andesitic Bulusan complex. Bulusan is flanked by several other large intracaldera lava domes and cones, including the prominent Mount Jormajan lava dome on the SW flank and Sharp Peak to the NE. The summit of Bulusan volcano is unvegetated and contains a 300-m-wide, 50-m-deep crater. Three small craters are located on the SE flank. Many moderate explosive eruptions have been recorded at Bulusan since the mid-19th century.
Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS) http://www.phivolcs.dost.gov.ph/index.php
ERTA ALE Ethiopia 13.60°N, 40.67°E; summit elev. 613 m
Scientists from the Afar Consortium Project observed the lava lake at Erta Ale during 21-23 November. They noted Strombolian activity from the lava lake in the southern pit crater. The lava lake had filled the pit crater and breached the W rim, spilling two lava flows into the main crater. The lava lake was encompassed by a scoria ring that was about 4 m high on the S side. By 23 November, the lake was above the scientist's eye level when they stood W of the southern pit in the main crater.
Geologic Summary. Erta Ale is an isolated basaltic shield volcano that is the most active volcano in Ethiopia. The broad, 50-km-wide volcano rises more than 600 m from below sea level in the barren Danakil depression. Erta Ale is the namesake and most prominent feature of the Erta Ale Range. The 613-m-high volcano contains a 0.7 x 1.6 km, elliptical summit crater housing steep-sided pit craters. Another larger 1.8 x 3.1 km wide depression elongated parallel to the trend of the Erta Ale range is located to the SE of the summit and is bounded by curvilinear fault scarps on the SE side. Fresh-looking basaltic lava flows from these fissures have poured into the caldera and locally overflowed its rim. The summit caldera is renowned for one, or sometimes two long-term lava lakes that have been active since at least 1967, or possibly since 1906.
Source: Afar Rift Consortium http://www.see.leeds.ac.uk/afar/index.html
KIZIMEN Eastern Kamchatka (Russia) 55.130°N, 160.32°E; summit elev. 2376 m
KVERT reported that volcanologists flying around Kizimen by helicopter on 20 November observed several new fumaroles at the summit and SW flank. A small amount of "dust" covered the SW flank, possibly from the new fumaroles. Seismic activity was above background levels during 19-26 November. The Level of Aviation Color Code was raised to Yellow.
Geologic Summary. Kizimen is an isolated, conical stratovolcano that is morphologically similar to Mount St. Helens prior to its 1980 eruption. The summit of Kizimen consists of overlapping lava domes, and blocky lava flows descend the flanks of the volcano, which is the westernmost of a volcanic chain north of Kronotsky volcano. The 2,376-m-high Kizimen was formed during four eruptive cycles beginning about 12,000 years ago and lasting 2,000-3,500 years. The largest eruptions took place about 10,000 and 8300-8400 years ago, and three periods of longterm lava-dome growth have occurred. The latest eruptive cycle began about 3,000 years ago with a large explosion and was followed by lava-dome growth lasting intermittently about 1,000 years. An explosive eruption about 1,100 years ago produced a lateral blast and created a 1.0 x 0.7 km wide crater breached to the NE, inside which a small lava dome (the fourth at Kizimen) has grown. A single explosive eruption, during 1927-28, has been recorded in historical time.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php
KLIUCHEVSKOI Central Kamchatka (Russia) 56.057°N, 160.638°E; summit elev. 4835 m
KVERT reported that seismic activity at Kliuchevskoi did not exceed background levels during 19-26 November. Strong fumarolic activity was observed daily and an ash plume rose to an altitude of 5 km (16,400 ft) a.s.l. on 24 November. Satellite imagery showed a thermal anomaly over the crater during 19-21 November and a gas-and-steam plume that drifted 111 km NE on 24 November. The Aviation Color Code level was raised to Orange.
Based on information from the Yelizovo Airport (UHPP), the Tokyo VAAC reported that on 25 November an ash plume rose to an altitude of 7.9 km (26,000 ft) a.s.l. and drifted E. Possible eruptions detected in satellite imagery on 27 and 29 November produced plumes that rose to altitudes of 5.8 km and 6.7 km (19,000 and 22,000 ft) a.s.l., respectively, and drifted NE.
Geologic Summary. Kliuchevskoi is Kamchatka's highest and most active volcano. Since its origin about 7,000 years ago, the beautifully symmetrical, 4,835-m-high basaltic stratovolcano has produced frequent moderate-volume explosive and effusive eruptions without major periods of inactivity. More than 100 flank eruptions, mostly on the NE and SE flanks of the conical volcano between 500 m and 3,600 m elevation, have occurred during the past 3,000 years. The morphology of its 700-m-wide summit crater has been frequently modified by historical eruptions, which have been recorded since the late-17th century. Historical eruptions have originated primarily from the summit crater, but have also included major explosive and effusive events from flank craters.
Sources: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php,
Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html
MERAPI Central Java (Indonesia) 7.542°S, 110.442°E; summit elev. 2968 m
CVGHM reported that avalanches on Merapi’s flanks were detected by the seismic network during 25-30 November. Although fog often prevented observations, white and brown plumes rising 100 m above the crater drifted SW on 25 November, and brownish plumes rose 300 m above the crater on 27 November. During 27-30 November, white plumes rose 100-800 m above the crater and drifted W, SW, N, and E. Incandescence from the crater was observed through cameras installed at the Merapi museum. According to news articles, a lahar in the Code River that runs through Yogyakarta, 30 km SSW, flooded streets and damaged bridges, and caused about 1,000 residents to evacuate. The Alert Level remained at 4, the highest level, on a scale of 1-4.
Geologic Summary. Merapi, one of Indonesia's most active volcanoes, lies in one of the world's most densely populated areas and dominates the landscape immediately N of the major city of Yogyakarta. The steep-sided modern Merapi edifice, its upper part unvegetated due to frequent eruptive activity, was constructed to the SW of an arcuate scarp cutting the eroded older Batulawang volcano. Pyroclastic flows and lahars accompanying growth and collapse of the steep-sided active summit lava dome have devastated cultivated and inhabited lands on the volcano's western-to-southern flanks and caused many fatalities during historical time. The volcano is the object of extensive monitoring efforts by the Merapi Volcano Observatory (MVO).
Sources: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://www.vsi.esdm.go.id/,
BNO News http://www.islandcrisis.net/2010/11/mount-merapis-mudflow-forces-hundreds-to-escape-in-indonesia/
TENGGER CALDERA Eastern Java (Indonesia) 7.942°S, 112.95°E; summit elev. 2329 m
According to the Darwin VAAC, CVGHM stated that an eruption from Tengger Caldera’s Bromo cone had occurred on 26 November. An ash plume detected in satellite imagery rose to an altitude of 13.7 km (45,000 ft) a.s.l. and dissipated. During 27-29 November satellite imagery showed ash plumes drifting 55-165 km at an altitude of 4.3 km (14,000 ft) a.s.l. According to news articles, Malang city's domestic airport, 25 km W, closed on 29 November. Meteorological clouds prevented observations during 29-30 November. The Alert Level remained at 4, the highest level, on a scale of 1-4.
Geologic Summary. The 16-km-wide Tengger caldera in eastern Java is located at the northern end of a volcanic massif extending from Semeru volcano. The massive Tengger volcanic complex consists of five overlapping stratovolcanoes, each truncated by a caldera. The most recent is the 9 x 10 km wide Sandsea caldera, which formed incrementally during the late Pleistocene and early Holocene. An overlapping cluster of post-caldera cones was constructed on the floor of the Sandsea caldera within the past several thousand years. The youngest of these is Bromo, one of Java's most frequently visited and most active volcanoes. More than 50 mild-to-moderate explosive eruptions have occurred since 1804.
Sources: Darwin Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AU/messages.html,
Agence France-Presse http://www.bangkokpost.com/breakingnews/208717/indonesia-closes-airport-as-volcano-rumbles
TUNGURAHUA Ecuador 1.467°S, 78.442°W; summit elev. 5023 m
The IG reported that on 22 November an explosion ejected incandescent blocks that fell onto the flanks 1.5 km below the crater rim, and produced an ash plume that rose to altitudes of 11-12 km (36,100-39,400 ft) a.s.l. Ashfall was reported in multiple areas to the W and SW. Smaller explosions produced ash plumes that rose to altitudes of 7-8 km (23,000-26,200 ft) a.s.l. and drifted NE and E. Lahars descended a SW drainage and temporarily dammed the Puela river. During 23-25 November, explosions produced ash plumes that rose less than 7 km (23,000 ft) a.s.l. Ashfall was reported in areas within 8 km N, NNE, W, and SW. Strombolian activity was seen at night.
During 25-26 and 29 November incandescent blocks were observed rolling down the flanks. During 26-30 November, steam-and-ash plumes rose to altitudes of 5.5-9 km (18,000-29,500 ft) a.s.l. and drifted SW and W. Plumes also drifted NW on 28 November. Ashfall was reported in areas within 8 km downwind, and roaring was occasionally reported. At night during 28-29 November Strombolian activity ejected blocks that rolled 400 m down the flanks. Satellite imagery on 29 November showed an increase in sulfur dioxide concentrations.
Geologic Summary. The steep-sided Tungurahua stratovolcano towers more than 3 km above its northern base. It sits ~140 km S of Quito, Ecuador's capital city, and is one of Ecuador's most active volcanoes. Historical eruptions have all originated from the summit crater. They have been accompanied by strong explosions and sometimes by pyroclastic flows and lava flows that reached populated areas at the volcano's base. The last major eruption took place from 1916 to 1918, although minor activity continued until 1925. The latest eruption began in October 1999 and prompted temporary evacuation of the town of Baños on the N side of the volcano.
Source: Instituto Geofísico-Escuela Politécnica Nacional (IG) http://www.igepn.edu.ec/
ULAWUN New Britain 5.05°S, 151.33°E; summit elev. 2334 m
Based on analyses of satellite imagery and information from RVO, the Darwin VAAC reported that on 26 November an ash plume from Ulawun rose to an altitude of 3.7 km (12,000 ft) a.s.l. and drifted 55 km NE.
Geologic Summary. The symmetrical basaltic to andesitic Ulawun stratovolcano is the highest volcano of the Bismarck arc, and one of Papua New Guinea's most frequently active. Ulawun rises above the N coast of New Britain opposite Bamus volcano. The upper 1,000 m of the 2,334-m-high volcano is unvegetated. A steep-walled valley cuts the NW side of the volcano, and a flank lava-flow complex lies to the S of this valley. Historical eruptions date back to the beginning of the 18th century. Twentieth-century eruptions were mildly explosive until 1967, but after 1970 several larger eruptions produced lava flows and basaltic pyroclastic flows, greatly modifying the summit crater.
Source: Darwin Volcanic Ash Advisory Centre (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AU/messages.html
Ongoing Activity
DUKONO Halmahera 1.68°N, 127.88°E; summit elev. 1335 m
Based on analyses of satellite imagery, the Darwin VAAC reported that during 23-27 November ash plumes from Dukono rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted 75-130 km W.
Geologic Summary. Reports from this remote volcano in northernmost Halmahera are rare, but Dukono has been one of Indonesia's most active volcanoes. More-or-less continuous explosive eruptions, sometimes accompanied by lava flows, occurred from 1933 until at least the mid-1990s, when routine observations were curtailed. During a major eruption in 1550, a lava flow filled in the strait between Halmahera and the N-flank cone of Gunung Mamuya. Dukono is a complex volcano presenting a broad, low profile with multiple summit peaks and overlapping craters. Malupang Wariang, 1 km SW of Dukono's summit crater complex, contains a 700 x 570 m crater that has also been active during historical time.
Source: Darwin Volcanic Ash Advisory Centre (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AU/messages.html
KARYMSKY Eastern Kamchatka (Russia) 54.05°N, 159.45°E; summit elev. 1536 m
KVERT reported that seismic activity from Karymsky was above background levels during 19-26 November, suggesting that possible ash plumes rose to an altitude of 5.5 km (18,000 ft) a.s.l. during 20-24 November. On 20 November, volcanologists surveying the volcano by helicopter observed gas-and-steam activity and noted that the upper flanks were covered with ash. Satellite imagery showed a daily thermal anomaly over the volcano and a gas-and-steam plume drifting 15 km SE on 22 November. The Aviation Color Code level remained at Orange.
Geologic Summary. Karymsky, the most active volcano of Kamchatka's eastern volcanic zone, is a symmetrical stratovolcano constructed within a 5-km-wide caldera that formed about 7,600-7,700 radiocarbon years ago. Construction of the Karymsky stratovolcano began about 2,000 years later. The latest eruptive period began about 500 years ago, following a 2,300-year quiescence. Much of the cone is mantled by lava flows less than 200 years old. Historical eruptions have been Vulcanian or Vulcanian-Strombolian with moderate explosive activity and occasional lava flows from the summit crater. Most seismicity preceding Karymsky eruptions has originated beneath Akademia Nauk caldera, which is located immediately S of Karymsky volcano and erupted simultaneously with Karymsky in 1996.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php
KATMAI Alaska Peninsula 58.280°N, 154.963°W; summit elev. 2047 m
Based on analysis of satellite imagery and information from AVO, the Anchorage VAAC reported that on 29 November strong winds in the Katmai area picked up loose ash deposited during the 1912 eruption and carried it SE over Kodiak Island. The Volcano Alert Level remained at Normal and the Aviation Color Code remained at Green.
Geologic Summary. Prior to 1912, Mount Katmai was a compound stratovolcano with four NE-SW-trending summits, most of which were truncated by caldera collapse in that year. Most of the two overlapping pre-1912 Katmai volcanoes are Pleistocene in age, but Holocene lava flows from a flank vent descend the SE flank of the SW stratovolcano into the Katmai River canyon. Katmai was initially considered to be the source of the Valley of Ten Thousand Smokes ash flow in 1912. However, the 3 x 4 km wide caldera of 1912 is now known to have formed as a result of the voluminous eruption at nearby Novarupta volcano. The steep walled young caldera has a jagged rim that rises 500-1,000 m above the caldera floor and contains a 250-m-deep, still-rising lake. Lake waters have covered a small post-collapse lava dome (Horseshoe Island) that was seen on the caldera floor at the time of the initial ascent to the caldera rim in 1916. Post-1912 glaciers have formed on a bench within Katmai caldera.
Source: Anchorage Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AK/messages.html
KILAUEA Hawaii (USA) 19.421°N, 155.287°W; summit elev. 1222 m
During 24-30 November, HVO reported that activity at Kilauea continued from the summit caldera and the east rift zone. At the summit caldera, the level of the lava-pool surface in the deep pit within Halema'uma'u crater remained mostly stable between approximately 140 and 145 m below the crater floor, periodically rising about 20 m above that level. Nighttime incandescence has been visible from the Jaggar Museum on the NW caldera rim since early 2010. A plume from the vent mostly drifted SW and deposited ash nearby.
At the east rift zone, lava continued to flow through the TEB lava-tube system and fed surface flows on the coastal plain, breakout flows W and N of a county viewing area (located along Highway 130), and one or more ocean entries on the Puhi-o-Kalaikini delta W of Kalapana Gardens subdivision. A lava flow that broke out of the tube on 24 November advanced towards an abandoned house in Kalapana Gardens, and on 27 November, set fire to and destroyed the structure. Incandescence was visible from vents on the N part of the Pu'u 'O'o crater floor on 23 November before it started to spatter and feed a small lava flow. The lava flow continued to advance E during 24 November-1 December.
Geologic Summary. Kilauea, one of five coalescing volcanoes that comprise the island of Hawaii, is one of the world's most active volcanoes. Eruptions at Kilauea originate primarily from the summit caldera or along one of the lengthy E and SW rift zones that extend from the caldera to the sea. About 90% of the surface of Kilauea is formed of lava flows less than about 1,100 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.
Source: US Geological Survey Hawaiian Volcano Observatory (HVO) http://hvo.wr.usgs.gov/
MANAM Northeast of New Guinea (SW Pacific) 4.080°S, 145.037°E; summit elev. 1807 m
RVO reported that during 19-25 November light brown to dark gray ash plumes were seen rising 400-500 m above Manam's South Crater. People living on the island reported occasional roaring and rumbling noises. Incandescent material ejected from the crater mainly fell back in and around the crater, but occasionally spilled into the SE and SW valleys. White vapor rose from Main Crater and incandescence from the crater was visible on most nights from 21 November onward.
Geologic Summary. The 10-km-wide island of Manam, lying 13 km off the northern coast of mainland Papua New Guinea, is one of the country's most active volcanoes. Four large radial valleys extend from the unvegetated summit of the conical 1807-m-high basaltic-andesitic stratovolcano to its lower flanks. These "avalanche valleys," regularly spaced 90 degrees apart, channel lava flows and pyroclastic avalanches that have sometimes reached the coast. Two summit craters are present; both are active, although most historical eruptions have originated from the southern crater, concentrating eruptive products during much of the past century into the SE avalanche valley. Frequent historical eruptions, typically of mild-to-moderate scale, have been recorded at Manam since 1616. Occasional larger eruptions have produced pyroclastic flows and lava flows that reached flat-lying coastal areas and entered the sea, sometimes impacting populated areas.
Source: Rabaul Volcano Observatory (RVO)
SAKURA-JIMA Kyushu 31.585°N, 130.657°E; summit elev. 1117 m
Based on information from JMA, the Tokyo VAAC reported that during 24 November-1 December explosions from Sakura-jima produced plumes that rose to altitudes of 1.2-1.8 km (4,000-6,000 ft) a.s.l. and drifted E, SE, and S. During 24 and 28-29 November, pilots reported that ash plumes rose to altitudes of 1.5-3 km (5,000-10,000 ft) a.s.l. and drifted SE and E.
Geologic Summary. 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 was associated with the formation of the 17 x 23-km-wide Aira caldera about 22,000 years ago. The construction of Sakura-jima began about 13,000 years ago 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 4,850 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.
Source: Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html
SARYCHEV PEAK Matua Island 48.092°N, 153.20°E; summit elev. 1496 m
Based on satellite image observations, SVERT reported that steam-and-gas emissions rose from Sarychev Peak on 28 November. Sarychev Peak does not have a seismic network; satellite imagery is the primary tool for monitoring many of the Kurile Islands volcanoes.
Geologic Summary. 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.
Source: Sakhalin Volcanic Eruption Response Team (SVERT) http://www.imgg.ru/rus/labs_vulcan_hazard.php
SHIVELUCH Central Kamchatka (Russia) 56.653°N, 161.360°E; summit elev. 3283 m
KVERT reported that moderate seismic activity from Shiveluch was detected during 19-26 November, suggesting that possible ash plumes rose to an altitude of 3.8 km (12,500 ft) a.s.l. A bright thermal anomaly over the volcano was observed in satellite imagery. Ash plumes that rose to an altitude of 5.8 km (19,000 ft) a.s.l. and strong gas-and-steam activity were observed on 19, 20, 22, and 24 November. Ash plumes observed in satellite imagery drifted 408 km E and S during 19-20 and 23-24 November. The Aviation Color Code level remained at Orange.
Based on analyses of satellite imagery, the Tokyo VAAC reported that on 30 November an eruption produced an ash plume that rose to an altitude of 4 km (13,000 ft) a.s.l. and drifted NE.
Geologic Summary. The high, isolated massif of Shiveluch volcano (also spelled Sheveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group and forms one of Kamchatka's largest and most active volcanoes. The currently active Molodoy Shiveluch lava-dome complex was constructed during the Holocene within a large breached caldera formed by collapse of the massive late-Pleistocene Strary Shiveluch volcano. At least 60 large eruptions of Shiveluch have occurred during the Holocene, making it the most vigorous andesitic volcano of the Kuril-Kamchatka arc. Frequent collapses of lava-dome complexes, most recently in 1964, have produced large debris avalanches whose deposits cover much of the floor of the breached caldera. Intermittent explosive eruptions began in the 1990s from a new lava dome that began growing in 1980. The largest historical eruptions from Shiveluch occurred in 1854 and 1964.
Sources: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php,
Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html
SUWANOSE-JIMA Ryukyu Islands (Japan) 29.635°N, 129.716°E; summit elev. 799 m
Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima during 27 November-1 December. Plumes rose to a maximum altitude of 1.5 km (5,000 ft) on 29 November.
Geologic Summary. 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, the NE summit crater, that began in 1949 and lasted nearly a half century. The largest historical eruption took place in 1813-14, when thick scoria deposits blanketed residential areas, after which the island was uninhabited for about 70 years. The SW crater produced lava flows that reached the western coast in 1813, and lava flows reached the eastern coast of the island in 1884.
Source: Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html
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