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  Volcanología
Actualizado el
09/09/2010 12:46h
Enviado por Fernando Raja
el 2010-09-02 17:41:28
VOLCANO: SI/USGS Weekly Volcanic Activity Report 25-31 August 2010

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.



New Activity/Unrest: Ekarma, Kuril Islands (Russia) / Galeras, Colombia / Manam, Northeast of New Guinea (SW Pacific) / Sinabung, Sumatra (Indonesia)

 
Ongoing Activity: Batu Tara, Komba Island (Indonesia) / Cleveland, Chuginadak Island / Dukono, Halmahera / Karymsky, Eastern Kamchatka (Russia) / Kilauea, Hawaii (USA) / Kliuchevskoi, Central Kamchatka (Russia) / Nevado del Huila, Colombia / Reventador, Ecuador / Sakura-jima, Kyushu / Sangay, Ecuador / Shiveluch, Central Kamchatka (Russia) / Soufrière Hills, Montserrat / Suwanose-jima, Ryukyu Islands (Japan)

 

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
 
 
EKARMA Kuril Islands (Russia) 48.958°N, 153.93°E; summit elev. 1170 m
 
SVERT reported that on 10 August scientists observed a vigorous steam plume from Ekarma that rose to an altitude of 1.8 km (5,900 ft) a.s.l. while visiting Sarychev Peak, 110 km SSW. On 24 August scientists visited Ekarma Island and observed continuous vigorous gas emissions from a new vent located on the S flank, about 250 m below the summit. The flanks had been blanketed by a layer of fine ash with a thickness exceeding 5 cm in the vicinity of the vent. Two recent lahar deposits were seen on the S flank. Based on their observations, SVERT speculated that a small eruption may have occurred between early June and late July 2010. Ekarma does not have a seismic network; satellite image analysis and infrequent ground observations are the primary tool for monitoring many of the Kuril Islands volcanoes.
 
Geologic Summary. 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.
 
Source: Sakhalin Volcanic Eruption Response Team (SVERT) http://www.imgg.ru/rus/labs_vulcan_hazard.php
 
 
GALERAS Colombia 1.22°N, 77.37°W; summit elev. 4276 m
 
An eruption from Galeras that began at 0400 on 25 August prompted INGEOMINAS to raise the Alert Level to I (Red; "imminent eruption or in progress"). Meteorological cloud cover initially prevented visual observations of the summit. Seismicity associated with the eruption continued for a period of about 12 hours and gradually declined in the afternoon. The Alert Level was lowered to II (Orange; "probable eruption in term of days or weeks"). Scientists aboard an overflight later that day observed ash-and-gas emissions from multiple areas of the active cone, and thermal anomalies that were detected on the N side of the cone. Ash fell to the NW, as far away as 30 km. According to news articles, about 7,000 were requested by officials to evacuate, although few left their homes. During 26-31 August at least 12 earthquakes, M 2-4, were located within a 2-km radius from the crater, at depths not more than 3 km. Gas plumes drifted NW, then S.
 
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.
 
Sources: Instituto Colombiano de Geología y Minería (INGEOMINAS) http://www.ingeominas.gov.co//,
CNN http://www.cnn.com/2010/WORLD/americas/08/25/colombia.volcano/index.html?section=cnn_latest
 
 
MANAM Northeast of New Guinea (SW Pacific) 4.080°S, 145.037°E; summit elev. 1807 m
 
RVO reported that during 13-26 August incandescence from Manam's South Crater was visible at night. Main Crater emitted diffuse white vapor. During 27-28 August incandescence emanated from both craters and brightened every 15-20 minutes. At that time, incandescent lava fragments ejected tens to hundreds of meters above South Crater were reported from observers in Bogia, about 23 km SSW. Weak explosions were heard at 15-20 minute intervals. During 28-29 August diffuse white-to-blue vapor emissions from Main Crater were occasionally accompanied by diffuse gray ash plumes. Incandescent lava fragments continued to be ejected. Based on analysis of satellite imagery, the Darwin VAAC reported that on 30 August an ash plume rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted 55 km NW.
 
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.
 
Sources: Rabaul Volcano Observatory (RVO),
Darwin Volcanic Ash Advisory Centre (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AU/messages.html
 
 
SINABUNG Sumatra (Indonesia) 3.17°N, 98.392°E; summit elev. 2460 m
 
CVGHM reported that on 28 August Sinabung emitted diffuse white plumes that rose 20 m and showed no signs of increased activity. On 29 August rumbling was heard, prompting authorizes to contact and move people living within a 6-km-radius of the volcano. Later that day, an explosion produced an ash plume that rose 1.5 km above the crater, and the Alert Level was raised to 4 (on a scale of 1-4). Media footage of the eruption at one point showed two closely spaced ash plumes from vents near the summit, causing domestic flights to be diverted. The next day a second, more powerful, explosion generated an ash plume that rose 2 km above the crater. The number of people media sources reported had evacuated ranged from 20,000-30,000. Ash fell in nearby areas and a strong sulfur odor was reported. Nighttime video showed incandescent material descending the flank of the volcano.
 
Geologic Summary. Gunung Sinabung is a Pleistocene-to-Holocene stratovolcano with many lava flows on its flanks.  The migration of summit vents along a N-S line gives the summit crater complex an elongated form.  The youngest crater of  this conical, 2460-m-high andesitic-to-dacitic volcano is at the southern end of the four overlapping summit craters.  An unconfirmed eruption was noted in 1881, and solfataric activity was seen at the summit and upper flanks of Sinabung in 1912, although no confirmed historical eruptions were recorded prior to 2010.    
 
Sources: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://portal.vsi.esdm.go.id/joomla/,
Associated Press http://news.yahoo.com/s/ap/20100830/ap_on_re_as/as_indonesia_volcano_erupts_16;_ylc=X3oDMTEwMGg1Nm1uBF9TAzIwMjM4Mjc1MjQEZW1haWxJZAMxMjgzMjEwMzAw,
Daily Mail http://www.dailymail.co.uk/news/worldnews/article-1307360/21k-people-evacuated-Indonesian-volcano-continues-spew-ash.html
 

 
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 26-28 August ash plumes from Batu Tara rose to an altitude of 1.5 km (5,000 ft) a.s.l. and drifted 55-75 km. The plumes drifted W and NW during 27-28 August.
 
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
 
 
CLEVELAND Chuginadak Island 52.825°N, 169.944°W; summit elev. 1730 m
 
AVO reported that on 26 August the Volcano Alert Level for Cleveland was raised to Advisory, and the Aviation Color Code was raised to Yellow, due to a persistent thermal anomaly near the summit visible in satellite imagery on most days during 16-24 August. Cloudy weather conditions prevented views of the summit during 25-29 August. A thermal anomaly was again seen in satellite imagery at night during 29-30 August. 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/
 
 
DUKONO Halmahera 1.68°N, 127.88°E; summit elev. 1335 m
 
Based on analyses of satellite imagery, the Darwin VAAC reported that during 25-29 August ash plumes from Dukono rose to altitudes of 2.1-3 km (7,000-10,000 ft) a.s.l. and drifted 35-110 km W and NE.
 
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 20-27 August seismic activity from Karymsky was above background levels and suggested that possible ash plumes rose to an altitude of 3.8 km (12,500 ft) a.s.l. Satellite imagery showed a thermal anomaly over the volcano during 20 and 23-24 August. 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
 
 
KILAUEA Hawaii (USA) 19.421°N, 155.287°W; summit elev. 1222 m
 
During 25-31 August 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 the floor of Halema'uma'u crater remained mostly stable; glow from the vent was also visible at night. A plume from the vent drifted SW. At Pu'u 'O'o crater, incandescence emanated from an active hornito on the N floor. At the east rift zone, lava that flowed through the TEB lava-tube system fed minor surface flows on the coastal plain, as well as two ocean entries at Puhi-o-Kalaikini, SW of Kalapana.
 
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/
 
 
KLIUCHEVSKOI Central Kamchatka (Russia) 56.057°N, 160.638°E; summit elev. 4835 m
 
KVERT reported that 20-27 August seismic activity from Kliuchevskoi was above background levels and lava flowed down the SW flank. Strombolian activity and gas-and-ash emissions were observed on 20 and 21 August. Cloud cover prevented observations the other days. Satellite imagery analyses showed a large and intense daily thermal anomaly from the volcano and ash plumes that drifted more than 200 km SE on 20 August. Based on analyses of satellite imagery and information from KEMSD, the Tokyo VAAC reported that an eruption on 28 August produced plumes that rose to altitudes of 7.6-10.4 km (25,000-34,000 ft) a.s.l. and drifted SE. Satellite imagery showed a possible eruption on 30 August. The Aviation Color Code level 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.
 
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
 
 
NEVADO DEL HUILA Colombia 2.93°N, 76.03°W; summit elev. 5364 m
 
According to the Washington VAAC, the Popayán Volcano Observatory (INGEOMINAS) received several reports from towns W of Nevado del Huila that indicated ash emissions on 30 August. Ash was not seen in satellite imagery, although extensive clouds were present in the area. A thermal anomaly was detected, however. INGEOMINAS reported that a pulse of tremor was detected, associated with an ash emission seen in the web camera at Tafxnú. Ashfall was later confirmed in Toribio, 27 km W.
 
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
 
 
REVENTADOR Ecuador 0.077°S, 77.656°W; summit elev. 3562 m
 
The Washington VAAC reported that on 30 August an ash plume was observed near Reventador by a pilot. Ash was not seen in satellite imagery.
 
Geologic Summary. Reventador is the most frequently active of a chain of Ecuadorian volcanoes in the Cordillera Real, well E of the principal volcanic axis. It is a forested stratovolcano that rises above the remote jungles of the western Amazon basin. A 3-km-wide caldera breached to the E was formed by edifice collapse and is partially filled by a young, unvegetated stratovolcano that rises about 1,300 m above the caldera floor. Reventador has been the source of numerous lava flows as well as explosive eruptions that were visible from Quito in historical time. Frequent lahars in this region of heavy rainfall have constructed a debris plain on the eastern floor of the caldera.
 
Source: Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html
 
 
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 during 26-31 August produced plumes that rose to altitudes of 1.2-2.1 km (4,000-7,000 ft) a.s.l. Some of the plumes drifted N and 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
 
 
SANGAY Ecuador 2.002°S, 78.341°W; summit elev. 5230 m
 
The Washington VAAC reported that on 30 August an ash plume was observed near Sangay by a pilot. Ash was not seen 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 August seismic activity from Shiveluch was above background levels, suggesting that possible ash plumes rose to an altitude of 8.5 km (27,900 ft) a.s.l. during 20-24 August. Gas-and-ash plumes were observed on 20 and 21 August. Satellite imagery analysis showed a thermal anomaly on the volcano during 20-22 and 24 August. The Aviation Color Code level 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 most of the rockfalls and pyroclastic flows detected during 20-27 August originated from a vertical face on the SE side of the lava dome and traveled W down Gages valley and E down the Tar River valley. The pyroclastic flows traveled no longer than 1.5 km and produced weakly convecting ash clouds that rose a few hundred meters. 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
 
Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima on 25 and 27 August. Details of possible resulting plumes were not reported.
 
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

 

 

Sally Kuhn Sennert - Weekly Report Editor
kuhns@si.edu
URL: http://www.volcano.si.edu/reports/usgs/

 

Map of Volcanoes Discussed this Week (Smithsonian - USGSG)



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