Smithsonian/USGS Weekly Volcanic Activity Report 7-13 September 2011
From: "Kuhn, Sally" <KUHNS@xxxxxx>
**************************************************************************************************************************
Smithsonian/USGS Weekly Volcanic Activity Report
7-13 September 2011
Sally Kuhn Sennert - Weekly Report Editor
kuhns@xxxxxx
URL: http://www.volcano.si.edu/reports/usgs/
New Activity/Unrest: | Cleveland, Chuginadak Island | Etna, Sicily (Italy) | Hierro, Canary Islands (Spain) | Ibu, Halmahera | Merapi, Central Java (Indonesia) | Ranakah, Flores Island (Indonesia) | Soputan, Sulawesi | Tambora, Sumbawa Island (Indonesia)
Ongoing Activity: | Batu Tara, Komba Island (Indonesia) | Dukono, Halmahera | Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaii (USA) | Kizimen, Eastern Kamchatka (Russia) | Puyehue-Cordón Caulle, Central Chile | Sakura-jima, Kyushu | 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
CLEVELAND Chuginadak Island 52.825°N, 169.944°W; summit elev. 1730 m
AVO reported that although cloud cover often prevented observations of Cleveland during 7-12 September, a thermal anomaly on the lava dome was visible during 8-9 and 12 September. A possible anomaly was visible on 10 September. The anomalies suggested that lava-dome growth was continuing, although no activity was observed in partly cloudy satellite images during 12-13 September. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange. No current seismic information was available because Cleveland does not have a real-time seismic network.
Geologic Summary. Symmetrical Mount Cleveland stratovolcano is situated at the western end of the uninhabited dumbbell-shaped Chuginadak Island in the east-central Aleutians. The 1,730-m-high stratovolcano is the highest of the Islands of Four Mountains group and is one of the most active in the Aleutians. Numerous large lava flows descend its flanks. It is possible that some 18th to 19th century eruptions attributed to Carlisle (a volcano located across the Carlisle Pass Strait to the NW) should be ascribed to Cleveland. In 1944 Cleveland produced the only known fatality from an Aleutian eruption. Recent eruptions from Mt. Cleveland have been characterized by short-lived explosive ash emissions, at times accompanied by lava fountaining and lava flows down the flanks.
Source: Alaska Volcano Observatory (AVO) http://www.avo.alaska.edu/
ETNA Sicily (Italy) 37.734°N, 15.004°E; summit elev. 3330 m
Sezione di Catania - Osservatorio Etneo reported that the thirteenth paroxysmal eruptive episode of 2011 took place at the New SE Crater of Etna on the morning of 8 September. Prior to the episode, a few emissions of ash from the New SE Crater occurred on 6 September. Sporadic, very weak Strombolian explosions from the crater started during the late evening on 7 September, and then continued in a subdued manner through the night.
On 8 September a series of ash emissions were followed by a rapid increase both in the intensity and frequency of Strombolian explosions. Loud detonations were audible across a vast sector of Etna's densely populated SE to E flanks. Simultaneously the volcanic tremor amplitude sharply increased and shifted from below the NE Crater toward the SE Crater. The Strombolian activity turned into a pulsating lava fountain, accompanied by increasing amounts of volcanic ash. Lava fountaining and ash emissions became more vigorous. Lava flowed through a deep breach in the E crater rim and along the fracture that had opened on the SE side of the cone during 29 August. The lava overflow was accompanied by repeated collapse and rockfalls from unstable portions of the cone in that area. Later brief periods of repeated emissions of brown ash mixed with white water vapor occurred from two or three vents on the N flank of the New SE Crater cone, in an area of the lava overflows from the N rim of the crater that had started shortly after the onset of the activity. The paroxysmal activity ceased in the evening and was followed by a series of progressively more passive ash emissions. Lava flows descended on the W slope of the Valle del Bove; expansion of the most advanced lava fronts continued for some time after feeding of the lava had ceased, mostly due to gravitational flow. Small active lava flows were observed for many hours after the cessation of the paroxysmal activity, remaining confined to the immediate vicinity of the crater.
The pyroclastic cone that grew around the New SE Crater during the recent series of eruptive episodes had undergone significant morphological changes. The S and N crater rims had further increased in height, whereas degradation and mass wasting on the SE flank had become more conspicuous. A large chunk of rock on the lower SE flank was rotated and uplifted, forming a steep-sided "spine" about 20-30 m tall, with locally vertical and sub-vertical flanks.
Geologic Summary. Mount Etna, towering above Catania, Sicily's second largest city, has one of the world's longest documented records of historical volcanism, dating back to 1500 BC. Historical lava flows cover much of the surface of this massive basaltic stratovolcano, the highest and most voluminous in Italy. Two styles of eruptive activity typically occur at Etna. Persistent explosive eruptions, sometimes with minor lava emissions, take place from one or more of the three prominent summit craters, the Central Crater, NE Crater, and SE Crater. Flank eruptions, typically with higher effusion rates, occur less frequently and originate from fissures that open progressively downward from near the summit. A period of more intense intermittent explosive eruptions from Etna's summit craters began in 1995. The active volcano is monitored by the Instituto Nazionale di Geofisica e Volcanologia (INGV) in Catania.
Source: Sezione di Catania - Osservatorio Etneo http://www.ct.ingv.it/
HIERRO Canary Islands (Spain) 27.73°N, 18.03°W; summit elev. 1500 m
The Spanish Geographic Institute (IGN) reported that since 16 July, seismicity at Hierro was high above the background levels. Until 7 September more than 6,200 events had been located, most of them in the El Golfo area with hypocenters that were 10 km deep, all magnitudes were below 3. The seismic activity alternated between relatively calm periods and high-energy periods. GPS local network stations showed deformations of about 2 cm. High rates of carbon dioxide flux were measured in the anomalous area.
Geologic Summary. The triangular island of Hierro is the SW-most and least studied of the Canary Islands. The massive Hierro shield volcano is truncated by a large NW-facing escarpment formed as a result of gravitational collapse of El Golfo volcano about 130,000 years ago. The steep-sided 1500-m-high scarp towers above a low lava platform bordering 12-km-wide El Golfo Bay, and three other large submarine landslide deposits occur to the SW and SE. Three prominent rifts oriented NW, NE, and south at 120 degree angles form prominent topographic ridges. The subaerial portion of the volcano consists of flat-lying Quaternary basaltic and trachybasaltic lava flows and tuffs capped by numerous young cinder cones and lava flows. Holocene cones and flows are found both on the outer flanks and in the El Golfo depression. Hierro contains the greatest concentration of young vents in the Canary Islands. Uncertainty surrounds the report of an historical eruption in 1793.
Source: National Geographic Institute of Spain (IGN) http://www.ign.es/ign/layout/volcaVolcanologia.do
IBU Halmahera 1.488°N, 127.63°E; summit elev. 1325 m
CVGHM reported mostly clear conditions at Ibu during January-8 September and that white-to-gray plumes were observed rising 200-400 m above the craters. On 20 August observers from the nearby villages of Goin and Duono noted multiple eruptions from the S, E, and N craters. Eruption "smoke" rose 50-250 m above the craters and an avalanche traveled 300 m. Seismicity indicating avalanches occurred on average 45 times per day during January-8 September. Other types of seismic signals fluctuated during the time period but stabilized or decreased towards September. Based on visual observations and seismicity, CVGHM lowered the Alert Level to 2 (on a scale of 1-4) on 8 September.
Geologic Summary. The truncated summit of Gunung Ibu stratovolcano along the NW coast of Halmahera Island has large nested summit craters. The inner crater, 1 km wide and 400 m deep, contained several small crater lakes through much of historical time. The outer crater, 1.2 km wide, is breached on the north side, creating a steep-walled valley. A large parasitic cone is located ENE of the summit. A smaller one to the WSW has fed a lava flow down the western flank. A group of maars is located below the northern and western flanks of the volcano. Only a few eruptions have been recorded from Ibu in historical time, the first a small explosive eruption from the summit crater in 1911. An eruption producing a lava dome that eventually covered much of the floor of the inner summit crater began in December 1998.
Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://portal.vsi.esdm.go.id/
MERAPI Central Java (Indonesia) 7.542°S, 110.442°E; summit elev. 2968 m
CVGHM reported that during 29 August-4 September white solfatara plumes rose at most 350 m above Merapi and drifted W. On 4 September small avalanches traveled 700 m SW. The Alert Level remained at 2 (on a scale of 1-4). Based on a pilot observation, the Darwin VAAC reported that on 8 September an ash plume rose to an altitude of 3.7 km (12,000 ft) a.s.l. and drifted almost 30 km N.
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://portal.vsi.esdm.go.id/,
Darwin Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AU/messages.html
RANAKAH Flores Island (Indonesia) 8.62°S, 120.52°E; summit elev. 2350 m
Based on visual observations and seismic data analyses of the Anak Ranakah lava dome since December 2010, CVGHM raised the Alert Level on 26 August to 2 (on a scale of 1-4). During 26 August-7 September white plumes rose 5-10 m above the lava dome. Seismic activity continued to increase, prompting CVGHM to again raised the Alert Level, to 3, on 8 September.
Geologic Summary. A new lava dome, named Anak Ranakah (Child of Ranakah) was formed in 1987 in an area without previous historical eruptions at the base of the large older lava dome of Gunung Ranakah. An arcuate group of lava domes extending westward from Gunung Ranakah occurs on the outer flanks of the poorly known Poco Leok caldera on western Flores Island. Pocok Mandosawa lava dome, at 2350 m the highest point on the island of Flores, lies west of Anak Ranakah.
Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://portal.vsi.esdm.go.id/
SOPUTAN Sulawesi 1.108°N, 124.73°E; summit elev. 1784 m
CVGHM reported that seismicity at Soputan significantly decreased after the eruption on 14 August until 7 September. White plumes rose at most 200 m above the crater during 14-18 August, up to 150 m above the crater during 19-28 August, and as high as 100 m above the crater during 29 August-7 September. The Alert Level was lowered to 2 (on a scale of 1-4) on 8 September. Visitors and residents were prohibited from going within a 4-km radius of the crater, a change from the 6-km restricted zone in place when the Alert level was at 3.
Geologic Summary. The small conical volcano of Soputan on the southern rim of the Quaternary Tondano caldera is one of Sulawesi's most active volcanoes. During historical time the locus of eruptions has included both the summit crater and Aeseput, a prominent NE-flank vent that formed in 1906 and was the source of intermittent major lava flows until 1924.
Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://portal.vsi.esdm.go.id/
TAMBORA Sumbawa Island (Indonesia) 8.25°S, 118.00°E; summit elev. 2850 m
Based on visual observation and seismic data, CVGHM reported an increase in activity at Tambora that started in April. Therefore, on 30 August, the Alert Level was raised to 2 (on a scale of 1-4). During 30 August-8 September seismicity continued to increase. Diffuse white plumes were observed on 5 September and rose 10 m above the crater rim. On 8 September the Alert Level was raised to 3 (on a scale of 1-4).
Geologic Summary. The massive Tambora stratovolcano forms the entire 60-km-wide Sanggar Peninsula on northern Sumbawa Island. The largely trachybasaltic-to-trachyandesitic volcano grew to about 4000 m elevation before forming a caldera more than 43,000 years ago. Late-Pleistocene lava flows largely filled the early caldera, after which activity changed to dominantly explosive eruptions during the early Holocene. Tambora was the source of history's largest explosive eruption, in April 1815. Pyroclastic flows reached the sea on all sides of the peninsula, and heavy tephra fall devastated croplands, causing an estimated 60,000 fatalities. The eruption of an estimated more than 150 cu km of tephra formed a 6-km-wide, 1250-m-deep caldera and produced global climatic effects. Minor lava domes and flows have been extruded on the caldera floor at Tambora during the 19th and 20th centuries.
Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://portal.vsi.esdm.go.id/
Ongoing Activity
BATU TARA Komba Island (Indonesia) 7.792°S, 123.579°E; summit elev. 748 m
Based on analyses of satellite imagery, the Darwin VAAC reported that during 8-13 September ash plumes from Batu Tara rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted 37-65 km NW and W.
Geologic Summary. The small isolated island of Batu Tara in the Flores Sea about 50 km north of Lembata (formerly Lomblen) Island contains a scarp on the eastern side similar to the Sciara del Fuoco of Italy's Stromboli volcano. Vegetation covers the flanks of Batu Tara to within 50 m of the 748-m-high summit. Batu Tara lies north of the main volcanic arc and is noted for its potassic leucite-bearing basanitic and tephritic rocks. The first historical eruption from Batu Tara, during 1847-52, produced explosions and a lava flow.
Source: Darwin Volcanic Ash Advisory Centre (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AU/messages.html
DUKONO Halmahera 1.68°N, 127.88°E; summit elev. 1335 m
Based on analyses of satellite imagery, the Darwin VAAC reported that on 13 September an ash plume from Dukono rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted 75 km NW.
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 during 2-9 September moderate seismic activity continued at Karymsky, indicating that possible ash plumes rose to an altitude of 3.5 km (11,500 ft) a.s.l. A thermal anomaly on the volcano was detected daily in satellite imagery. The Aviation Color Code 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
KILAUEA Hawaii (USA) 19.421°N, 155.287°W; summit elev. 1222 m
During 31 August-6 September, HVO reported that the level of the lava-lake surface in the deep pit within Kilauea's Halema'uma'u crater periodically fluctuated and circulated. Almost daily measurements indicated that the gas plume from the vent continued to deposit variable amounts of ash and occasionally fresh spatter nearby. At Pu'u 'O'o' crater, lava from E, W, and S-central sources on the crater floor fed an eastern and a western perched lava lake during 7-8 September. Lava also covered much of the crater floor, rising to within 5 m of a low point on the E crater rim. During 9-10 September a large amount of lava from a new source of effusion at the NE edge of the crater covered most of the crater floor. On 10 September a pilot confirmed that lava overtopped the E rim and fed a short lava flow. Not long after that the effusion rate decreased and lava fed only the two perched lava lakes. During 11-13 September the lava lakes mostly circulated and, by 12 September, had overflowed onto the crater floor.
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/
KIZIMEN Eastern Kamchatka (Russia) 55.130°N, 160.32°E; summit elev. 2376 m
KVERT reported that during 2-9 September the magnitude of volcanic earthquakes at Kizimen remained high; about 1,000 earthquakes were detected daily. Satellite images showed a large thermal anomaly on the volcano. Lava on the E flank continued to flow and video images showed strong fumarolic activity. The Aviation Color Code remained at Orange.
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
PUYEHUE-CORDON CAULLE Central Chile 40.590°S, 72.117°W; summit elev. 2236 m
Based on seismicity during 7-13 September, OVDAS-SERNAGEOMIN reported that the eruption from the Cordón Caulle rift zone, part of the Puyehue-Cordón Caulle volcanic complex, continued at a low level. Although cloudy weather mostly prevented observations of the vent, plumes detected in satellite imagery during 7-8, 10, and 12 September drifted 10-60 km NE, E, and SE. A plume observed by an area camera on 12 September rose less than 1 km above the crater. The next day a plume rose less than 4 km above the crater and was observed in satellite imagery drifting 35 km NE. The Alert Level remained at Red.
Geologic Summary. The Puyehue-Cordón Caulle volcanic complex (PCCVC) is a large NW-SE-trending late-Pleistocene to Holocene basaltic-to-rhyolitic transverse volcanic chain SE of Lago Ranco. The 1799-m-high Pleistocene Cordillera Nevada caldera lies at the NW end, separated from Puyehue stratovolcano at the SE end by the Cordón Caulle fissure complex. The Pleistocene Mencheca volcano with Holocene flank cones lies NE of Puyehue. The basaltic-to-rhyolitic Puyehue volcano is the most geochemically diverse of the PCCVC. The flat-topped, 2236-m-high Puyehue volcano was constructed above a 5-km-wide caldera and is capped by a 2.4-km-wide summit caldera of Holocene age. Lava flows and domes of mostly rhyolitic composition are found on the eastern flank of Puyehue. Historical eruptions originally attributed to Puyehue, including major eruptions in 1921-22 and 1960, are now known to be from the Cordón Caulle rift zone. The Cordón Caulle geothermal area, occupying a 6 x 13 km wide volcano-tectonic depression, is the largest active geothermal area of the southern Andes volcanic zone.
Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN) http://www.sernageomin.cl/
SAKURA-JIMA Kyushu 31.585°N, 130.657°E; summit elev. 1117 m
Based on information from JMA, the Tokyo VAAC reported that during 9-13 September explosions from Sakura-jima produced plumes that rose to altitudes of 1.8-2.7 km (6,000-9,000 ft) a.s.l. and drifted NW and N. On 9 September a pilot observed an ash plume that rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted NW.
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
SHIVELUCH Central Kamchatka (Russia) 56.653°N, 161.360°E; summit elev. 3283 m
KVERT reported that seismic activity at Shiveluch was moderate during 2-9 September, and indicated that possible ash plumes rose to an altitude of 4.3 km (14,100 ft) a.s.l. during 2-3 September. Ground-based observers noted fumarolic activity during the week, and an ash plume that rose to an altitude of 4 km (19,700 ft) a.s.l. on 3 September. Also on 3 September an ash cloud 19 by 11 km was observed in satellite imagery drifting 20 km E. A thermal anomaly on the volcano was also observed in satellite imagery on 5 and 7 September. The Aviation Color Code remained at Orange.
Based on information from KEMSD, the Tokyo VAAC reported that on 10 September an eruption produced a plume that rose to an altitude of 6.7 km (22,000 ft) a.s.l.
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 an explosion from Suwanose-jima on 12 September. That same day an eruption produced a plume that rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted W.
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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Sally Kuhn Sennert
SI/USGS Weekly Volcanic Activity Report Editor
Global Volcanism Program
http://www.volcano.si.edu/reports/usgs/
Smithsonian Institution, National Museum of Natural History
Department of Mineral Sciences, MRC-119
Washington, D.C., 20560
Phone: 202.633.1805
Fax: 202.357.2476
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