VOLCANO: SI/USGS Weekly Volcanic Activity Report 25 November-1 December 2009

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SI/USGS Weekly Volcanic Activity Report 25 November-1 December 2009
From: "Sally Kuhn Sennert " <KUHNS@xxxxxx>
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Sally Kuhn Sennert - Weekly Report Editor kuhns@xxxxxx
URL: http://www.volcano.si.edu/reports/usgs/
 
 
New Activity/Unrest: | Galeras, Colombia | Gaua, Banks Islands (SW Pacific) | Karkar, Northeast of New Guinea (SW Pacific) | Sarychev Peak, Matua Island
 
Ongoing Activity: | Chaitén, Southern Chile | Dukono, Halmahera | Fuego, Guatemala | Karymsky, Eastern Kamchatka | Kilauea, Hawaii (USA) | Kliuchevskoi, Central Kamchatka (Russia) | Nevado del Huila, Colombia | Rabaul, New Britain | Sakura-jima, Kyushu | Sangay, Ecuador | Shiveluch, Central Kamchatka (Russia) | Soufrière Hills, Montserrat | 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
 
 
GALERAS Colombia 1.22°N, 77.37°W; summit elev. 4276 m
 
On 27 November, INGEOMINAS lowered the Alert Level for Galeras to III (Yellow; "changes in the behavior of volcanic activity"). During the previous few days, seismicity was low and occasionally punctuated by signals indicative of minor gas and ash emissions. An overflight on 26 November revealed gas emissions from the interior walls of the main crater and thermal anomalies with temperatures of 200 degrees Celsius. During 27 November-1 December, seismicity remained low; signals indicated gas emissions.
 
Geologic Summary. Galeras, a stratovolcano with a large breached caldera located immediately W of the city of Pasto, is one of Colombia's most frequently active volcanoes. The dominantly andesitic Galeras volcanic complex has been active for more than 1 million years, and two major caldera collapse eruptions took place during the late Pleistocene. Longterm extensive hydrothermal alteration has affected the volcano. This has contributed to large-scale edifice collapse that has occurred on at least three occasions, producing debris avalanches that swept to the W and left a large horseshoe-shaped caldera inside which the modern cone has been constructed. Major explosive eruptions since the mid Holocene have produced widespread tephra deposits and pyroclastic flows that swept all but the southern flanks. A central cone slightly lower than the caldera rim has been the site of numerous small-to-moderate historical eruptions since the time of the Spanish conquistadors.
 
Source: Instituto Colombiano de Geología y Minería (INGEOMINAS) http://www.ingeominas.gov.co//
 
 
GAUA Banks Islands (SW Pacific) 14.27°S, 167.50°E; summit elev. 797 m
 
The Vanuatu Geohazards Observatory reported that a large explosion from Gaua's Mount Garat on 18 November was followed by high dense ash plumes. Seismicity increased on 25 October and remained significant through 24 November. According to news articles, an explosion that caused ashfall in inhabited areas on 26 November prompted the evacuation of more than 300 people. The Alert Level was raised to 4, the second highest level on a scale of 0-5.
 
Geologic Summary. The roughly 20-km-diameter Gaua Island, also known as Santa Maria, consists of a basaltic-to-andesitic stratovolcano with an 6 x 9 km wide summit caldera. Small parasitic vents near the caldera rim fed Pleistocene lava flows that reached the coast on several sides of the island; several littoral cones were formed where these lava flows reached the sea. Quiet collapse that formed the roughly 700-m-deep caldera was followed by extensive ash eruptions. Construction of the historically active cone of Mount Garat (Gharat) and other small cinder cones in the SW part of the caldera has left a crescent-shaped caldera lake. The symmetrical, flat-topped Mount Garat cone is topped by three pit craters. The onset of eruptive activity from a vent high on the SE flank of Mount Garat in 1962 ended a long period of dormancy.
 
Sources: Vanuatu Geohazards Observatory http://www.geohazards.gov.vu/,
Agence France-Presse http://www.nst.com.my/Current_News/NST/articles/20091126142958/Article
 
 
KARKAR Northeast of New Guinea (SW Pacific) 4.649°S, 145.964°E; summit elev. 1839 m
 
Based on analyses of satellite imagery, the Darwin VAAC reported that an eruption from Karkar on 25 November produced a plume that rose to an altitude of 13.7 km (45,000 ft) a.s.l. The report also stated that ash had merged with a thunderstorm cloud and had become unidentifiable. Another ash plume identified on 26 November rose to an altitude of 9.1 km (30,000 ft) a.s.l. Confirmation of ash emissions was not available from RVO at the time of the posting of this report.
 
Geologic Summary. Karkar is a 19 x 25 km wide, forest-covered island that is truncated by two nested summit calderas. The 5.5-km-wide outer caldera was formed during one or more eruptions, the last of which occurred 9000 years ago. The eccentric 3.2-km-wide inner caldera was formed sometime between 1500 and 800 years ago. Parasitic cones are present on the northern and southern flanks of basaltic-to-andesitic Karkar volcano; a linear array of small cones extends from the northern rim of the outer caldera nearly to the coast. Most historical eruptions, which date back to 1643, have originated from Bagiai cone, a pyroclastic cone constructed within the steep-walled, 300-m-deep inner caldera. The floor of the caldera is covered by young, mostly unvegetated andesitic lava flows.
 
Source: Darwin Volcanic Ash Advisory Centre (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AU/messages.html
 
 
SARYCHEV PEAK Matua Island 48.092°N, 153.20°E; summit elev. 1496 m
 
SVERT reported that a thermal anomaly on Sarychev Peak was detected by satellite on 25 November. Steam-and-gas emissions were noted on 25, 26, and 29 November.
 
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
 
 
Ongoing Activity
 
 
CHAITEN Southern Chile 42.833°S, 72.646°W; summit elev. 1122 m
 
Based on analyses of satellite imagery, the Buenos Aires VAAC reported that on 26 November a diffuse plume from Chaitén's lava-dome complex drifted ENE.
 
Geologic Summary. Chaitén is a small, glacier-free caldera with a Holocene lava dome located 10 km NE of the town of Chaitén on the Gulf of Corcovado. A pyroclastic-surge and pumice deposit considered to originate from the eruption that formed the elliptical 2.5 x 4 km wide summit caldera was dated at about 9400 years ago. A rhyolitic, 962-m-high obsidian lava dome occupies much of the caldera floor. Obsidian cobbles from this dome found in the Blanco River are the source of prehistorical artifacts from archaeological sites along the Pacific coast as far as 400 km away from the volcano to the north and south. The caldera is breached on the SW side by a river that drains to the bay of Chaitén, and the high point on its southern rim reaches 1122 m.
 
Source: Buenos Aires Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AG/messages.html
 
 
DUKONO Halmahera 1.68°N, 127.88°E; summit elev. 1335 m
 
The Darwin VAAC reported that on 30 November an ash plume from Dukono at an altitude of 3 km (10,000 ft) a.s.l. was observed on satellite imagery 75 km E.
 
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
 
 
FUEGO Guatemala 14.473°N, 90.880°W; summit elev. 3763 m
 
Based on analyses of satellite imagery, the Washington VAAC reported that on 29 November a small plume from Fuego, possibly containing ash, drifted 10 km SW. A thermal anomaly was also detected. On 30 November and 1 December, INSIVUMEH reported that explosions produced ash plumes that rose to altitudes of 4.3-4.7 km (14,100-15,400 ft) a.s.l. and drifted 8-15 km W and SW. Rumbling noises were noted and incandescent block avalanches were generated.
 
Geologic Summary. Volcán Fuego, one of Central America's most active volcanoes, is one of three large stratovolcanoes overlooking Guatemala's former capital, Antigua. The scarp of an older edifice, Meseta, lies between 3,763-m-high Fuego and its twin volcano to the N, Acatenango. Construction of Meseta volcano continued until the late Pleistocene or early Holocene, after which growth of the modern Fuego volcano continued the southward migration of volcanism that began at Acatenango. Frequent vigorous historical eruptions have been recorded at Fuego since the onset of the Spanish era in 1524, and have produced major ashfalls, along with occasional pyroclastic flows and lava flows. The last major explosive eruption from Fuego took place in 1974, producing spectacular pyroclastic flows visible from Antigua.
 
Sources: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH) http://www.insivumeh.gob.gt/,
Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html
 
 
KARYMSKY Eastern Kamchatka 54.05°N, 159.45°E; summit elev. 1536 m
 
KVERT reported that seismic activity at Karymsky was above background levels on 23 and 25 November; data were not available on the other days during 20-27 November due to technical reasons. Elevated seismicity possibly indicated that ash plumes rose to an altitude of 3.8 km (12,500 ft) a.s.l. Analyses of satellite imagery revealed a daily thermal anomaly and ash plumes that drifted 120 km E on 23 and 25 November. The Level of Concern 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 25 November-1 December, HVO reported that lava flowed SE from beneath Kilauea's Thanksgiving Eve Breakout (TEB) and rootless shield complex through a lava tube system, reaching the ocean at multiple locations between Waikupanaha and an area 700 m farther to the W. A small bench collapse may have occurred on 27 November. Thermal anomalies detected by satellite and visual observations revealed active surface lava flows on the coastal plain. Incandescence was occasionally seen on the Pu'u 'O'o crater floor.
 
The vent in Halema'uma'u crater continued to produce a white or off-white plume that drifted mainly SW and dropped small amounts of ash downwind. Incandescence originated from a lava pond deep in the vent cavity floor; the lava pond circulated and spattered during 25-26 November and 1 December. Measurements indicated that the sulfur dioxide emission rate at the summit remained elevated; 1,000 tonnes per day were measured on 28 and 30 November. The 2003-2007 average rate was 140 tonnes per day.
 
According to a news article on 30 November, Hawaii county was declared a natural disaster area due to the negative impact that vog from Halema'uma'u crater has had on croplands and livestock.
 
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.
 
Sources: US Geological Survey Hawaiian Volcano Observatory (HVO) http://hvo.wr.usgs.gov/,
Hawaii News Now http://www.hawaiinewsnow.com/global/story.asp?s=11592445
 
 
KLIUCHEVSKOI Central Kamchatka (Russia) 56.057°N, 160.638°E; summit elev. 4835 m
 
KVERT reported that during 20-27 November seismic activity from Kliuchevskoi was above background levels and lava continued to flow down the ESE flank. Strombolian activity ejected tephra 300 m above the crater during 21-25 November. Satellite imagery revealed a large daily thermal anomaly at the volcano. The Level of Concern Color Code remained at Orange.
 
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.
 
Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php
 

NEVADO DEL HUILA Colombia 2.93°N, 76.03°W; summit elev. 5364 m
 
INGEOMINAS reported that during 25 November-1 December gas plumes from Nevado del Huila were seen on the web camera rising 8.4 km (27,600 ft) a.s.l. and drifting downwind. Seismicity included both tremor indicative of gas emissions and hybrid earthquakes. An overflight on 25 November revealed that the newest lava dome had continued to grow. Based on pilot observations, the Washington VAAC reported that on 26 November a gas plume, possibly containing ash, rose to an altitude of 7.6 km (25,000 ft) a.s.l. Ash was not identified in satellite imagery, although low weather clouds were present in the area. A sulfur dioxide plume was emitted on 30 November at a calculated rate of 3,900 tons per day. The Alert Level remained at II (Orange; "probable eruption in term of days or weeks").
 
Geologic Summary. Nevado del Huila, the highest active volcano in Colombia, is an elongated N-S-trending volcanic chain mantled by a glacier icecap. The andesitic-dacitic volcano was constructed within a 10-km-wide caldera. Volcanism at Nevado del Huila has produced six volcanic cones whose ages in general migrated from south to north. Two glacier-free lava domes lie at the southern end of the Huila volcanic complex. The first historical eruption from this little known volcano took place in the 16th century. Two persistent steam columns rise from the central peak, and hot springs are also present.
 
Sources: Instituto Colombiano de Geología y Minería (INGEOMINAS) http://www.ingeominas.gov.co//,
Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html
 
 
RABAUL New Britain 4.271°S, 152.203°E; summit elev. 688 m
 
RVO reported that during 20-26 November thick white plumes and gray ash plumes rose from Rabaul caldera's Tavurvur cone. Strong explosions produced ash plumes that rose 1.5 km above the summit and showered the flanks with lava fragments that were incandescent at night. Shock waves rattled windows in the Kokopo area, about 20 km SE. Occasionally, incandescence from the summit crater was noted.
 
Geologic Summary. The low-lying Rabaul caldera on the tip of the Gazelle Peninsula at the NE end of New Britain forms a broad sheltered harbor. The outer flanks of the 688-m-high asymmetrical pyroclastic shield volcano are formed by thick pyroclastic-flow deposits. The 8 x 14 km caldera is widely breached on the E, where its floor is flooded by Blanche Bay. Two major Holocene caldera-forming eruptions at Rabaul took place as recently as 3,500 and 1,400 years ago. Three small stratovolcanoes lie outside the northern and NE caldera rims. Post-caldera eruptions built basaltic-to-dacitic pyroclastic cones on the caldera floor near the NE and western caldera walls. Several of these, including Vulcan cone, which was formed during a large eruption in 1878, have produced major explosive activity during historical time. A powerful explosive eruption in 1994 occurred simultaneously from Vulcan and Tavurvur volcanoes and forced the temporary abandonment of Rabaul city.
 
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 explosions from Sakura-jima on 26 November and 1 December produced plumes that rose to altitudes of 1.8-2.7 km (6,000-9,000 ft) a.s.l. and drifted SW and E. Ash was seen in satellite imagery on 26 November.
 
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
 
 
SANGAY Ecuador 2.002°S, 78.341°W; summit elev. 5230 m
 
Based on a pilot observation, the Washington VAAC reported that on 1 December an ash plume from Sangay rose to an altitude of 7.9 km (26,000 ft) a.s.l. and drifted W. Ash was not identified in satellite imagery, although low weather clouds were present in the area. Later that day, an eruption was reported, but ash was again unidentifiable in satellite imagery.
 
Geologic Summary. The isolated Sangay volcano, located E of the Andean crest, is the southernmost of Ecuador's volcanoes, and its most active. It has been in frequent eruption for the past several centuries. The steep-sided, 5,230-m-high glacier-covered volcano grew within horseshoe-shaped calderas of two previous edifices, which were destroyed by collapse to the E, producing large debris avalanches that reached the Amazonian lowlands. The modern edifice dates back to at least 14,000 years ago. Sangay towers above the tropical jungle on the E side; on the other sides flat plains of ash from the volcano have been sculpted by heavy rains into steep-walled canyons up to 600 m deep. The earliest report of an historical eruption was in 1628. More or less continuous eruptions were reported from 1728 until 1916, and again from 1934 to the present. The more or less constant eruptive activity has caused frequent changes to the morphology of the summit crater complex.
 
Source: Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html
 
 
SHIVELUCH Central Kamchatka (Russia) 56.653°N, 161.360°E; summit elev. 3283 m
 
KVERT reported that during 20-27 November seismic activity from Shiveluch was above background levels, possibly indicating that ash plumes rose to an altitude of 4.3 km (14,100 ft) a.s.l. Fumarolic activity was seen using a video camera. Analyses of satellite imagery revealed a large daily thermal anomaly from the lava dome. The Level of Concern Color Code remained at Orange.
 
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.
 
Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php
 
 
SOUFRIERE HILLS Montserrat 16.72°N, 62.18°W; summit elev. 915 m
 
MVO reported that during 20-27 November activity from the Soufrière Hills lava dome continued at a high level. Activity increased on 21 November and periods of tremor were detected on 23 November. Lava extrusion during this period shifted from the W side of the lava dome to the summit region. As a result, abundant pyroclastic flows traveled NE down Tuitt's Ghaut on 23 November for the first time in several weeks. On 24 November there was a period of 120 minutes of continuous pyroclastic flow activity, followed by 90 minutes of semi-continuous activity. The pyroclastic flows traveled W down Gages Valley and into Spring Ghaut, and NE down Tuitt's Ghaut and Whites Bottom Ghaut reaching Tuitt's village. Associated ash plumes rose to an altitude of 6.1 km (20,000 ft) a.s.l. On 26 November, a pyroclastic flow that descended the Tar River valley was caused by collapse of part of the old, pre-2009 lava dome. Ashfall occurred in Old Towne and parts of Olveston. Incandescent material seen in a photograph taken at night on 29 November traveled down the flanks of the lava dome in several areas. The Hazard Level remained at 3.
 
Geologic Summary. The complex dominantly andesitic Soufrière Hills volcano occupies the southern half of the island of Montserrat. The summit area consists primarily of a series of lava domes emplaced along an ESE-trending zone. English's Crater, a 1-km-wide crater breached widely to the E, was formed during an eruption about 4,000 years ago in which the summit collapsed, producing a large submarine debris avalanche. Block-and-ash flow and surge deposits associated with dome growth predominate in flank deposits at Soufrière Hills. Non-eruptive seismic swarms occurred at 30-year intervals in the 20th century, but with the exception of a 17th-century eruption that produced the Castle Peak lava dome, no historical eruptions were recorded on Montserrat until 1995. Long-term small-to-moderate ash eruptions beginning in that year were later accompanied by lava-dome growth and pyroclastic flows that forced evacuation of the southern half of the island and ultimately destroyed the capital city of Plymouth, causing major social and economic disruption.
 
Source: Montserrat Volcano Observatory (MVO) http://www.mvo.ms/
 
 
SUWANOSE-JIMA Ryukyu Islands (Japan) 29.635°N, 129.716°E; summit elev. 799 m
 
The Tokyo VAAC reported that on 26 November an ash plume from Suwanose-jima was seen by a pilot 65 km S drifting NE at an altitude of 3 km (10,000 ft) a.s.l.
 
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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