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SI/USGS Weekly Volcanic Activity Report 27 October-2 November 2010
From: "Kuhn, Sally" <KUHNS@xxxxxx>
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SI/USGS Weekly Volcanic Activity Report
27 October-2 November 2010
Sally Kuhn Sennert - Weekly Report Editor
URL: http://www.volcano.si.edu/reports/usgs/
New Activity/Unrest: | Colima, México | Kliuchevskoi, Central Kamchatka (Russia) | Krakatau, Indonesia | Merapi, Central Java (Indonesia) | Piton de la Fournaise, Reunion Island | Planchón-Peteroa, Central Chile-Argentina border | Shiveluch, Central Kamchatka (Russia)
Ongoing Activity: | Dukono, Halmahera | Eyjafjallajökull, Southern Iceland | Fuego, Guatemala | Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaii (USA) | Manam, Northeast of New Guinea (SW Pacific) | Pagan, Mariana Islands (Central Pacific) | Sakura-jima, Kyushu | Sangay, Ecuador | Santa María, Guatemala | Villarrica, Central Chile
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
COLIMA México 19.514°N, 103.62°W; summit elev. 3850 m
Based on analysis of satellite imagery, the Washington VAAC reported that an ash cloud from Colima drifted W on 28 October.
Geologic Summary. The Colima volcanic complex is the most prominent volcanic center of the western Mexican Volcanic Belt. It consists of two southward-younging volcanoes, Nevado de Colima (the 4,320 m high point of the complex) on the N and the historically active Volcán de Colima on the S. Volcán de Colima (also known as Volcán Fuego) is a youthful stratovolcano constructed within a 5-km-wide caldera, breached to the S, that has been the source of large debris avalanches. Major slope failures have occurred repeatedly from both the Nevado and Colima cones, and have produced a thick apron of debris-avalanche deposits on three sides of the complex. Frequent historical eruptions date back to the 16th century. Occasional major explosive eruptions (most recently in 1913) have destroyed the summit and left a deep, steep-sided crater that was slowly refilled and then overtopped by lava dome growth.
Source: Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html
KLIUCHEVSKOI Central Kamchatka (Russia) 56.057°N, 160.638°E; summit elev. 4835 m
KVERT reported that during 22-29 October seismic activity at Kliuchevskoi was above background levels and Strombolian activity was observed. Satellite imagery analyses showed a large and intense daily thermal anomaly over the volcano and two lava flows descending the W and SW flanks from the summit crater. Ash plumes also detected in imagery drifted more than 2,300 km E. Ash plumes rose to altitudes of 8-9 km (26,200-29,500 ft) a.s.l. during 22-25 and 27 October. The Aviation Color Code level remained at Red. A news article from 29 October stated that ash from Kliuchevskoi and Shiveluch caused area flight diversions.
On 30 October explosive activity decreased along with the magnitude of volcanic tremor. Based on visual observations and analysis of satellite imagery, ash plumes rose to altitudes of 5-5.5 km (16,400-18,000 ft) a.s.l. and drifted 100 km SE. The Aviation Color Code level was lowered to Orange. The Tokyo VAAC reported that, based on analyses of satellite imagery and information from KVERT, eruptions on 31 October and 2 November, and a possible eruption on 1 November produced ash plumes that rose to altitudes of 5.2-6.7 km (17,000-22,000 ft) a.s.l. and drifted SE and E.
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,
Associated Press http://www.mmail.com.my/content/53705-two-russian-volcanoes-erupt-forcing-flights-divert
KRAKATAU Indonesia 6.102°S, 105.423°E; summit elev. 813 m
A news report on 2 November noted that the frequency of explosions from Anak Krakatau had slowly increased to 100 per day since 25 October. During 31 October-1 November there were 251 explosions recorded.
Geologic Summary. Renowned Krakatau volcano lies in the Sunda Strait between Java and Sumatra. Collapse of the ancestral Krakatau edifice, perhaps in 416 AD, resulted in a 7-km-wide caldera. Remnants of this volcano formed Verlaten and Lang Islands; subsequently Rakata, Danan and Perbuwatan volcanoes were formed, coalescing to create the pre-1883 Krakatau Island. Caldera collapse during the catastrophic 1883 eruption destroyed Danan and Perbuwatan volcanoes, and left only a remnant of Rakata volcano. The post-collapse cone of Anak Krakatau (Child of Krakatau), constructed within the 1883 caldera at a point between the former cones of Danan and Perbuwatan, has been the site of frequent eruptions since 1927.
Source: Jakarta Post http://www.thejakartapost.com/news/2010/11/02/anak-krakatau-continues-spewing-toxic-gas.html
MERAPI Central Java (Indonesia) 7.542°S, 110.442°E; summit elev. 2968 m
According to the Darwin VAAC, ground-based reports indicated an eruption from Merapi on 28 October. Cloud cover prevented satellite observations. CVGHM reported that two pyroclastic flows occurred on 30 October. According to a news article, ash fell in Yogyakarta, 30 km SSW, causing low visibility. CVGHM noted four pyroclastic flows the next day.
On 1 November an eruption began mid-morning with a low-frequency earthquake and avalanches. About seven pyroclastic flows occurred during the next few hours, traveling SSE a maximum distance of 4 km. A gas-and-ash plume rose 1.5 km above the crater and drifted E and N. CVGHM recommended that evacuees from several communities within a 10-km radius should continue to stay in shelters or safe areas. The Darwin VAAC reported that a possible eruption on 1 November produced an ash plume that rose to an altitude of 6.1 km (20,000 ft) a.s.l., according to ground-based reports, analyses of satellite imagery, and web camera views. On 2 November an ash plume was seen in satellite imagery drifting 75 km N at an altitude of 6.1 km (20,000 ft) a.s.l. News outlets noted diversions and cancellations of flights in and out of the Solo (40 km E) and Yogyakarta airports. The Alert Level remained at 4 (on a scale of 1-4).
CVGHM reported 26 pyroclastic flows on 2 November. A mid-day report on 3 November stated that 38 pyroclastic flows occurred during the first 12 hours of the day. An observer from the Kaliurang post saw 19 of those 38 flows travel 4 km S. Plumes from the pyroclastic flows rose 1.2 km, although dense fog made visual observations difficult. Ashfall was noted in some nearby areas.
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/,
Darwin Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AU/messages.html,
BBC News http://www.bbc.co.uk/news/world-asia-pacific-11673186
PITON DE LA FOURNAISE Reunion Island 21.231°S, 55.713°E; summit elev. 2632 m
OVPDLF reported that an eruption from Piton de la Fournaise that began on 14 October from a fissure near the Château Fort crater, about 1.5 km SE of the Dolomieu crater rim, continued during 27-30 October. On 27 October steam plumes rose from the main vent (Cone 3) and lava flows were active. A sudden increase in tremor intensity was detected. The next day material was ejected from Cone 3, along with gas and steam. A small lava lake was observed in the cone, and lava flows continued to be active on the field. Tremor slightly decreased, and then significantly decreased on 29-30 October. No further tremor was recorded on 31 October and OVPDLF stated that the eruption had stopped.
Geologic Summary. Massive Piton de la Fournaise shield volcano on the island of Réunion is one of the world's most active volcanoes. Most historical eruptions have originated from the summit and flanks of a 400-m-high lava shield, Dolomieu, that has grown within the youngest of three large calderas. This depression is 8 km wide and is breached to below sea level on the eastern side. More than 150 eruptions, most of which have produced fluid basaltic lava flows within the caldera, have been documented since the 17th century. The volcano is monitored by the Piton de la Fournaise Volcano Observatory, one of several operated by the Institut de Physique du Globe de Paris.
Source: Observatoire Volcanologique du Piton de la Fournaise (OVPDLF) http://www.ipgp.fr/pages/03030810.php
PLANCHON-PETEROA Central Chile-Argentina border 35.240°S, 70.570°W; summit elev. 4107 m
SERNAGEOMIN reported that during 15-25 October seismic activity from Planchón-Peteroa was low. Observations based on images from a camera installed in the town of Romeral (approximately 60 km NW) and photos sent by staff from a mining company (65 km WNW) showed that plume color changed from gray to white on 13 October. The plume was smaller, with heights of less than 200 m above the crater. Satellite imagery analyses corroborated the ground-based observations. On 27 October, the Alert Level was lowered to 3, Yellow.
Geologic Summary. Planchón-Peteroa is an elongated complex volcano along the Chile-Argentina border with several overlapping calderas. Activity began in the Pleistocene with construction of the basaltic-andesite to dacitic Volcán Azufre, followed by formation of basaltic and basaltic-andesite Volcán Planchón, 6 km to the N. About 11,500 years ago, much of Azufre and part of Planchón collapsed, forming the massive Río Teno debris avalanche, which reached Chile's Central Valley. Subsequently, Volcán Planchón II was formed. The youngest volcano, andesitic and basaltic-andesite Volcá Peteroa, consists of scattered vents between Azufre and Planchón. Peteroa has been active into historical time and contains a small steaming crater lake. Historical eruptions from the Planchón-Peteroa complex have been dominantly explosive, although lava flows were erupted in 1837 and 1937.
Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN) http://www.sernageomin.cl/
SHIVELUCH Central Kamchatka (Russia) 56.653°N, 161.360°E; summit elev. 3283 m
KVERT reported that seismic activity from Shiveluch began to increase on 27 October. The magnitude of volcanic tremor then sharply increased on 28 October, indicating a strong explosive eruption. Cloud cover prevented observations of the volcano, but ash plumes possibly rose to an altitude of 10 km (32,800 ft) a.s.l. Ash fell in Ust-Kamchatsk, 85 km SE, a few hours later. The road from Ust-Kamchatsk to Kliuchi, 50 km SW, closed due to poor visibility and darkness. Satellite images indicated that the ash plume rose to an altitude of 12 km (39,400 ft) a.s.l. and drifted E. The Aviation Color Code level was raised to Red. According to news articles, ash from Shiveluch and Kliuchevskoi caused area flight diversions.
On 29 October satellite imagery showed the ash plume drifting 2,500 km E; ash continued to fall in Ust-Kamchatsk. Ash explosions continued on 30 October. Seismic data suggested that ash plumes rose to an altitude of 10 km (32,800 ft) a.s.l. and drifted NE. The Aviation Color Code level was lowered to Orange. Based on analyses of satellite imagery and information from KVERT, the Tokyo VAAC reported that possible eruptions on 31 October and during 1-2 November produced ash plumes that rose to altitudes of 3.7-6.7 km (12,000-22,000 ft) a.s.l. and drifted SE and E. Subsequent notices on 31 October and 1 November stated that ash had dissipated.
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,
Associated Press http://www.mmail.com.my/content/53705-two-russian-volcanoes-erupt-forcing-flights-divert
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 1-2 November ash plumes from Dukono rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted 45-75 km NW and SW.
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
EYJAFJALLAJOKULL Southern Iceland 63.63°N, 19.62°W; summit elev. 1666 m
According to a news article from 27 October, a scientist at the University of Iceland Institute of Earth Sciences noted that the eruption of Eyjafjallajökull, that began as a fissure eruption on 20 March 2010 and later continued from the summit caldera on 14 April, was over. Ash was last seen rising from the caldera in June.
Geologic Summary. Eyjafjallajökull (also known as Eyjafjöll) is located west of Katla volcano. Eyjafjallajökull consists of an E-W-trending, elongated ice-covered basaltic-andesite stratovolcano with a 2.5-km-wide summit caldera. Fissure-fed lava flows occur on both the eastern and western flanks of the volcano, but are more prominent on the western side. Although the 1666-m-high volcano has erupted during historical time, it has been less active than other volcanoes of Iceland's eastern volcanic zone, and relatively few Holocene lava flows are known. An intrusion beneath the south flank from July-December 1999 was accompanied by increased seismic activity and was constrained by tilt measurements, GPS-geodesy and InSAR. The last historical eruption of Eyjafjallajökull prior to an eruption in 2010 produced intermediate-to-silicic tephra from the central caldera during December 1821 to January 1823.
Source: Iceland Review http://icelandreview.com/icelandreview/daily_news/?cat_id=16539&ew_0_a_id=369471
FUEGO Guatemala 14.473°N, 90.880°W; summit elev. 3763 m
During 28-29 October, INSIVUMEH reported that explosions from Fuego produced ash plumes that rose 300-600 m above the crater. Incandescent material was ejected 75 m above the crater, and rumbling and degassing sounds were occasionally heard. Avalanches descended the W flank. On 18 October, ashfall was reported in Sangre de Cristo, 10 km WSW. Based on analyses of satellite imagery, the Washington VAAC reported that on 31 October an ash cloud was detected up to 20 km W of Fuego.
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 (Russia) 54.05°N, 159.45°E; summit elev. 1536 m
KVERT reported that seismic activity from Karymsky was above background levels during 21-23 October and at background levels during 24-29 October. Satellite imagery showed a thermal anomaly over the volcano during 22-25 October and an ash plume that drifted 40 km E on 23 October. 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 27 October-2 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 160 and 170 m below the crater floor. Periodically the lava rose a few meters above that level, producing nighttime incandescence seen from the Jaggar Museum, on the NW caldera rim. A plume from the vent drifted SW and deposited ash nearby.
At the east rift zone, lava continued to flow through the TEB lava-tube system and fed two ocean entries at the Puhi-o-Kalaikini delta. On 27 October a small lava flow broke out of the lava tube and was active W of the end of Highway 130. A channelized 'a'a lava flow at the base of the pali began the next day. Lava flows were active on the coastal plain during 29-30 October and 1-2 November. Incandescence was frequently visible from vents on the N part of the Pu'u 'O'o 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/
MANAM Northeast of New Guinea (SW Pacific) 4.080°S, 145.037°E; summit elev. 1807 m
Based on analysis of satellite imagery and pilot observations, the Darwin VAAC reported that on 28 October an ash plume from Manam rose to an altitude of 4.6 km (15,000 ft) a.s.l. and drifted about 95 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.
Source: Darwin Volcanic Ash Advisory Centre (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AU/messages.html
PAGAN Mariana Islands (Central Pacific) 18.13°N, 145.80°E; summit elev. 570 m
Low-level gas-and-steam plumes from Pagan were observed in satellite imagery during 24 and 26-27 October. The Aviation Color Code remained at Yellow and the Volcano Alert Level remained at Advisory. Pagan is not monitored with ground-based geophysical instrumentation; the only source of information is satellite observation and occasional reports from observers who visit the island.
Geologic Summary. Pagan Island, the largest and one of the most active of the Marianas Islands volcanoes, consists of two stratovolcanoes connected by a narrow isthmus. Both North and South Pagan stratovolcanoes were constructed within calderas, 7 and 4 km in diameter, respectively. The 570-m-high Mount Pagan at the NE end of the island rises above the flat floor of the caldera, which probably formed during the early Holocene. South Pagan is a 548-m-high stratovolcano with an elongated summit containing four distinct craters. Almost all of the historical eruptions of Pagan, which date back to the 17th century, have originated from North Pagan volcano. The largest eruption of Pagan during historical time took place in 1981 and prompted the evacuation of the sparsely populated island.
Source: Emergency Management Office of the Commonwealth of the Mariana Islands, Office of the Governor, United States Geological Survey Volcano Hazards Program http://volcanoes.usgs.gov/nmi/activity/index.php
SAKURA-JIMA Kyushu 31.585°N, 130.657°E; summit elev. 1117 m
Based on information from JMA, the Tokyo VAAC reported that an eruption from Sakura-jima on 31 October produced a plume that rose to an altitude of 1.5 km (6,000 ft) a.s.l. and drifted NE. On 2 November a pilot reported that an ash plume rose to an altitude of 1.5 km (6,000 ft) a.s.l. and drifted SE.
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 29 October a thermal anomaly from Sangay was seen in satellite imagery. A narrow steam-and-gas plume possibly containing some ash was also detected.
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
SANTA MARIA Guatemala 14.756°N, 91.552°W; summit elev. 3772 m
INSIVUMEH reported that on 29 October an explosion from Santa María's Santiaguito lava dome complex produced ash plumes that rose 900 m above Caliente dome and drifted SW. A weak pyroclastic flow from the lava dome traveled down the SE flank. Ashfall was reported in the Finca La Florida (5 km S), and Palajunoj and San José on the SW flank. Based on analyses of satellite imagery, the Washington VAAC reported that on 31 October an ash cloud drifted W.
Geologic Summary. Symmetrical, forest-covered Santa María volcano is one of a chain of large stratovolcanoes that rises dramatically above the Pacific coastal plain of Guatemala. The stratovolcano has a sharp-topped, conical profile that is cut on the SW flank by a large, 1-km-wide crater, which formed during a catastrophic eruption in 1902 and extends from just below the summit to the lower flank. The renowned Plinian eruption of 1902 followed a long repose period and devastated much of SW Guatemala. The large dacitic Santiaguito lava-dome complex has been growing at the base of the 1902 crater since 1922. Compound dome growth at Santiaguito has occurred episodically from four westward-younging vents, accompanied by almost continuous minor explosions and periodic lava extrusion, larger explosions, pyroclastic flows, and lahars.
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
VILLARRICA Central Chile 39.42°S, 71.93°W; summit elev. 2847 m
Based on Significant Meteorological Information (SIGMET) advisories and web camera views, the Buenos Aires VAAC reported that during 1-2 November ash plumes from Villarrica rose to altitudes of 3.7-4.6 km (12,000-15,000 ft) a.s.l. and drifted N, NE, E, and ESE. Ash was not detected on satellite imagery. On 2 November a steam-and-gas plume drifted NE.
Geologic Summary. Villarrica, one of Chile's most active volcanoes, rises above the lake and town of the same name. It is the westernmost of three large stratovolcanoes that trend perpendicular to the Andean chain. A 6-km wide caldera formed during the late Pleistocene, more than 0.9 million years ago. A 2-km-wide postglacial caldera is located at the base of the presently active, dominantly basaltic-to-andesitic cone at the NW margin of the Pleistocene caldera. About 25 scoria cones dot Villarrica's flanks. Plinian eruptions and pyroclastic flows have been produced during the Holocene from this dominantly basaltic volcano, but historical eruptions have consisted largely of mild-to-moderate explosive activity with occasional lava effusion. Lahars from the glacier-covered volcano have damaged towns on its flanks.
Source: Buenos Aires Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AG/messages.html
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