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Smithsonian/USGS Weekly Volcanic Activity Report 17-23 November 2010
From: "Venzke, Ed" <VENZKEE@si.edu>
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Smithsonian/USGS Weekly Volcanic Activity Report
17-23 November 2010
Sally Kuhn Sennert - Weekly Report Editor
kuhns@si.edu
URL: http://www.volcano.si.edu/reports/usgs/
New Activity/Unrest: | Bulusan, Luzon | Kizimen, Eastern Kamchatka (Russia) | Merapi, Central Java (Indonesia) | Semeru, Eastern Java (Indonesia) | Shiveluch, Central Kamchatka (Russia) | Tengger Caldera, Eastern Java (Indonesia) | Tungurahua, Ecuador
Ongoing Activity: | Batur, Bali (Indonesia) | Dukono, Halmahera | Fuego, Guatemala | Gorely, Southern Kamchatka (Russia) | Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaii (USA) | Kliuchevskoi, Central Kamchatka (Russia) | Krakatau, Indonesia | Rinjani, Lombok Island (Indonesia) | Sakura-jima, Kyushu | Santa María, Guatemala | Suwanose-jima, Ryukyu Islands (Japan)
The Weekly Volcanic Activity Report is a cooperative project between the Smithsonian's Global Volcanism Program and the US Geological Survey's Volcano Hazards Program. Updated by 2300 UTC every Wednesday, notices of volcanic activity posted on these pages are preliminary and subject to change as events are studied in more detail. This is not a comprehensive list of all of Earth's volcanoes erupting during the week, but rather a summary of activity at volcanoes that meet criteria discussed in detail in the "Criteria and Disclaimers" section. Carefully reviewed, detailed reports on various volcanoes are published monthly in the Bulletin of the Global Volcanism Network.
Note: Many news agencies do not archive the articles they post on the Internet, and therefore the links to some sources may not be active. To obtain information about the cited articles that are no longer available on the Internet contact the source.
New Activity/Unrest
BULUSAN Luzon 12.770°N, 124.05°E; summit elev. 1565 m
On 16 November, white steam rose from Bulusan's NW vent, but no steaming was observed from the crater and SE vent. Cloud cover prevented observations the next day. On 18 November weak steaming from the crater and known thermal vents produced plumes that drifted downslope to the SW. Cloud cover obscured views of the crater during 19-20 November. An explosion-type earthquake on 21 November was coincident with rumbling sounds and an ash plume that rose 2 km above the crater. Ashfall up to 3 mm thick was reported in multiple areas. According to news reports, about 500 families evacuated and some local roads were impassable. Steam was emitted from the crater and known thermal vents during 22-23 November.
Geologic Summary. Luzon's southernmost volcano, Bulusan, was constructed within the 11-km-diameter dacitic Irosin caldera, which was formed more than 36,000 years ago. A broad, flat moat is located below the prominent SW caldera rim; the NE rim is buried by the andesitic Bulusan complex. Bulusan is flanked by several other large intracaldera lava domes and cones, including the prominent Mount Jormajan lava dome on the SW flank and Sharp Peak to the NE. The summit of Bulusan volcano is unvegetated and contains a 300-m-wide, 50-m-deep crater. Three small craters are located on the SE flank. Many moderate explosive eruptions have been recorded at Bulusan since the mid-19th century.
Sources: Philippine Institute of Volcanology and Seismology (PHIVOLCS) http://www.phivolcs.dost.gov.ph/,
Philippine Daily Inquirer http://newsinfo.inquirer.net/breakingnews/regions/view/20101121-304505/Sorsogon-town-in-st ate-of-calamity-as-volcano-spews-worsen,
Malaya http://www.malaya.com.ph/11222010/news5.html
KIZIMEN Eastern Kamchatka (Russia) 55.130°N, 160.32°E; summit elev. 2376 m
Based on information from the Yelizovo Airport (UHPP), the Tokyo VAAC reported that on 17 November an ash plume from Kizimen rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted NE.
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: Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html
MERAPI Central Java (Indonesia) 7.542°S, 110.442°E; summit elev. 2968 m
CVGHM reported that on 15 November no pyroclastic flows descended Merapi's flanks and few avalanches were detected compared to the previous day. During 16-18 November, the number of seismic signals and the number of avalanches both continued to decrease. Although fog often prevented observations, a gas-and-ash plume was observed rising 1.5 km above the crater and drifting SW. A steam plume rose 250 m above the crater and drifted W. On 18 November a pyroclastic flow occurred with low intensity. Lahar deposits were seen in multiple drainages. CVGHM noted areas that remained within a 10-20 km danger zone. On 21 November one pyroclastic flow was detected and five were recorded the next day. During 21-23 November avalanches continued to occur. Lahars traveling S on 23 November carried material up to 100 cm in diameter. According to news articles, the Yogyakarta airport resumed operations on 20 November. The death toll from the eruption reached 322 and more than 130,000 people continued to live in temporary shelters.
Based on analysis of satellite imagery, the Darwin VAAC reported that during 16-21 November ash plumes rose to altitudes of 4.6-6.1 km (15,000-20,000 ft) a.s.l. and drifted 55-165 km W and NW.
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,
Agence France-Presse http://www.abc.net.au/news/stories/2010/11/20/3072108.htm,
South African Press Association and Agence France-Presse http://www.timeslive.co.za/world/article778677.ece/Indonesia-volcano-death-toll-rises-to-3 22
SEMERU Eastern Java (Indonesia) 8.108°S, 112.92°E; summit elev. 3676 m
Based on analysis of satellite imagery, the Darwin VAAC reported that during 18-19 November ash plumes from Semeru rose to an altitude of 4.3 km (14,000 ft) a.s.l. and drifted 75-110 N and NW. Sulfur dioxide gas concentrations were detected 75 km SW.
Geologic Summary. Semeru is the highest volcano on Java and one of its most active. The symmetrical stratovolcano rises abruptly to 3,676 m above coastal plains to the S and lies at the southern end of a volcanic massif extending N to the Tengger caldera. Semeru has been in almost continuous eruption since 1967. Frequent small-to-moderate Vulcanian eruptions have accompanied intermittent lava dome extrusion, and periodic pyroclastic flows and lahars have damaged villages below the volcano. A major secondary lahar on 14 May 1981 caused more than 250 deaths and damaged 16 villages.
Source: Darwin Volcanic Ash Advisory Centre (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AU/messages.html
SHIVELUCH Central Kamchatka (Russia) 56.653°N, 161.360°E; summit elev. 3283 m
KVERT reported that moderate seismic activity from Shiveluch was detected during 12-19 November, suggesting that possible ash plumes rose to an altitude of 3.5 km (11,500 ft) a.s.l. Two distinct thermal anomalies over the volcano observed in satellite imagery showed the hot lava dome and recent pyroclastic flow deposits from an eruption on 27 October. During 11-14 November, satellite imagery showed ash plumes drifting 100 km N and E, and ash clouds with dimensions as large as 60 by 32 km. Gas-and-steam activity was observed during 16-18 November; cloud cover prevented visual observations the other days. The Aviation Color Code level remained at Orange.
Based on analyses of satellite imagery and information from KVERT, the Tokyo VAAC reported that during 19-21 and 23 November eruptions produced plumes that rose to altitudes of 4.6-5.2 km (15,000-17,000 ft) a.s.l. and drifted NE, E, and SE.
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
TENGGER CALDERA Eastern Java (Indonesia) 7.942°S, 112.95°E; summit elev. 2329 m
CVGHM reported that during November seismicity from Tengger Caldera increased, and volcanic tremor was first detected on 8 November. The heights of gas-and-steam plumes increased during the month, going from 75 m above the crater during 1-7 November to100-250 m above the crater during 8-23 November. The Alert Level was raised to 3 (on a scale of 1-4) on 23 November. Residents and tourists were not permitted within a 3-km-radius of the active crater. Later that night, seismic activity increased and a white-to-gray plume rose 200-300 m above the crater. The Alert Level was raised to 4. The tourist areas surrounding Tengger Caldera was closed.
Geologic Summary. The 16-km-wide Tengger caldera in eastern Java is located at the northern end of a volcanic massif extending from Semeru volcano. The massive Tengger volcanic complex consists of five overlapping stratovolcanoes, each truncated by a caldera. The most recent is the 9 x 10 km wide Sandsea caldera, which formed incrementally during the late Pleistocene and early Holocene. An overlapping cluster of post-caldera cones was constructed on the floor of the Sandsea caldera within the past several thousand years. The youngest of these is Bromo, one of Java's most frequently visited and most active volcanoes. More than 50 mild-to-moderate explosive eruptions have occurred since 1804.
Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://www.vsi.esdm.go.id/
TUNGURAHUA Ecuador 1.467°S, 78.442°W; summit elev. 5023 m
Based on Air Force Weather Agency (AFWA) reports, pilot observations, and analyses of satellite imagery, the Washington VAAC reported that on 22 November an eruption from Tungurahua produced an ash plume that rose to an altitude of 7.6 km (25,000 ft) a.s.l. and drifted 37 km SW. Subsequent satellite images showed a detached ash cloud that became difficult to discern in images about 230 km SW of the volcano. Pilots reported additional ash emissions that rose to an altitude of 6.4 km (21,000 ft) a.s.l. On 23 November satellite images showed an ash plume drifting S. IG reported that an ash plume rose to an altitude of 7 km (23,000 ft) a.s.l.
Geologic Summary. The steep-sided Tungurahua stratovolcano towers more than 3 km above its northern base. It sits ~140 km S of Quito, Ecuador's capital city, and is one of Ecuador's most active volcanoes. Historical eruptions have all originated from the summit crater. They have been accompanied by strong explosions and sometimes by pyroclastic flows and lava flows that reached populated areas at the volcano's base. The last major eruption took place from 1916 to 1918, although minor activity continued until 1925. The latest eruption began in October 1999 and prompted temporary evacuation of the town of Baños on the N side of the volcano.
Source: Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html
Ongoing Activity
BATUR Bali (Indonesia) 8.242°S, 115.375°E; summit elev. 1717 m
CVGHM reported that seismicity from Batur decreased from 1 June to 17 November and fumarolic plumes rose from the crater. On 19 November the Alert level was lowered to Normal, or 1 (on a scale of 1-4).
Geologic Summary. The historically active Batur volcano is located at the center of two concentric calderas NW of Agung volcano in eastern Bali. The SE side of the larger 10 x 13 km caldera contains a caldera lake. The inner 7.5-km-wide caldera, which was formed during emplacement of the Bali (or Ubud) ignimbrite, has been dated at either 23,670 or 28,500 years ago. The SE wall of the inner caldera lies beneath Lake Batur; Batur cone has been constructed within the inner caldera to a height above the outer caldera rim. The Batur stratovolcano has produced vents over much of the inner caldera, but a NE-SW fissure system has localized the Batur I, II, and III craters along the summit ridge. Historical eruptions have been characterized by mild-to-moderate explosive activity sometimes accompanied by lava flows from summit and flank vents that have reached the caldera floor and the shores of Lake Batur.
Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://www.vsi.esdm.go.id/
DUKONO Halmahera 1.68°N, 127.88°E; summit elev. 1335 m
Based on analyses of satellite imagery, the Darwin VAAC reported that on 23 November an ash plume from Dukono rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted 130 km W.
Geologic Summary. Reports from this remote volcano in northernmost Halmahera are rare, but Dukono has been one of Indonesia's most active volcanoes. More-or-less continuous explosive eruptions, sometimes accompanied by lava flows, occurred from 1933 until at least the mid-1990s, when routine observations were curtailed. During a major eruption in 1550, a lava flow filled in the strait between Halmahera and the N-flank cone of Gunung Mamuya. Dukono is a complex volcano presenting a broad, low profile with multiple summit peaks and overlapping craters. Malupang Wariang, 1 km SW of Dukono's summit crater complex, contains a 700 x 570 m crater that has also been active during historical time.
Source: Darwin Volcanic Ash Advisory Centre (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AU/messages.html
FUEGO Guatemala 14.473°N, 90.880°W; summit elev. 3763 m
During 18-22 November, INSIVUMEH reported that explosions from Fuego produced ash plumes that rose as high as 1 km above the crater and drifted S, SW, and W. Incandescent material was ejected 100 m above the crater and avalanches occurred. Ashfall was reported in areas downwind, including in villages 10 km W. Some explosions were accompanied by rumbling noises and shock waves detected as far away as 8 km.
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.
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH) http://www.insivumeh.gob.gt/
GORELY Southern Kamchatka (Russia) 52.558°N, 158.03°E; summit elev. 1829 m
KVERT reported that during 12-19 November seismic activity from Gorely was above background levels and volcanic tremor continued to be detected. Gas-and-steam emissions were observed during 12-14 and 16-18 November. Clouds obscured the volcano on the other days. Satellite imagery showed a gas-and-steam plume drifting 40 km NE on 12 November and a weak thermal anomaly over the volcano during 12-14 and 18 November. The Aviation Color Code level remained at Yellow.
Geologic Summary. Gorely volcano, one of the most active in southern Kamchatka, consists of five small overlapping stratovolcanoes constructed along a WNW-ESE line within a large 9 x 13.5 km late-Pleistocene caldera. The massive Gorely complex contains 11 summit and 30 flank craters. During the early Holocene, activity was characterized by frequent mild eruptions with occasional larger explosions and lava flows that filled in the caldera. Quiescent periods became longer between 6,000 and 2,000 years ago, after which the activity was mainly explosive. About 600-650 years ago intermittent strong explosions and lava flow effusion accompanied frequent mild eruptions. Historical eruptions have consisted of vulcanian and phreatic explosions of moderate volume.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php
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 11-19 November, suggesting that possible ash plumes rose to an altitude of 5.2 km (17,100 ft) a.s.l. on 13 and 17 November. Satellite imagery showed a thermal anomaly over the volcano during 11-18 November. Ash clouds with dimensions as large as 23 x 10 km were detected in imagery 82 km NE on 16 November and 15 km NE on 17 November. The Aviation Color Code level remained at Orange.
Geologic Summary. Karymsky, the most active volcano of Kamchatka's eastern volcanic zone, is a symmetrical stratovolcano constructed within a 5-km-wide caldera that formed about 7,600-7,700 radiocarbon years ago. Construction of the Karymsky stratovolcano began about 2,000 years later. The latest eruptive period began about 500 years ago, following a 2,300-year quiescence. Much of the cone is mantled by lava flows less than 200 years old. Historical eruptions have been Vulcanian or Vulcanian-Strombolian with moderate explosive activity and occasional lava flows from the summit crater. Most seismicity preceding Karymsky eruptions has originated beneath Akademia Nauk caldera, which is located immediately S of Karymsky volcano and erupted simultaneously with Karymsky in 1996.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php
KILAUEA Hawaii (USA) 19.421°N, 155.287°W; summit elev. 1222 m
During 17-23 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 approximately 150 m below the crater floor, periodically rising about 20 m above that level. Nighttime incandescence has been visible from the Jaggar Museum on the NW caldera rim since early 2010. A plume from the vent deposited ash nearby.
At the east rift zone, lava continued to flow through the TEB lava-tube system and fed small weakly active surface flows on the coastal plain, breakout flows W of a county viewing area (located along Highway 130), and a single ocean entry on the Puhi-o-Kalaikini delta W of Kalapana Gardens subdivision. Incandescence was visible from vents on the N part of the Pu'u 'O'o crater floor during 17-18 November. Spattering from the vent was seen during 18-19 November, and a slow-moving lava flow began at about noon on 19 November.
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 seismic activity at Kliuchevskoi was above background levels during 12-14 November and at background levels during 15-19 November. A weak thermal anomaly over the volcano was detected daily in satellite imagery. Fumarolic activity was observed during 16-18 November; cloud cover prevented observations on the other days. Satellite imagery also showed an ash plume that drifted 40 km NE on 13 November and a gas-and-steam plume that drifted 28 km NE the next day. The Aviation Color Code level remained at Yellow.
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
KRAKATAU Indonesia 6.102°S, 105.423°E; summit elev. 813 m
According to NASA's Earth Observatory, a satellite image shows an ash-and-gas plume rising from Anak Krakatau on 17 November.
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: NASA Earth Observatory http://earthobservatory.nasa.gov/
RINJANI Lombok Island (Indonesia) 8.42°S, 116.47°E; summit elev. 3726 m
CVGHM reported that during June-15 November seismicity from Rinjani decreased; visual observations indicated no activity since August. On 19 November the Alert level was lowered to Normal, or 1 (on a scale of 1-4).
Geologic Summary. Rinjani volcano on the island of Lombok rises to 3,726 m, second in height among Indonesian volcanoes only to Sumatra's Kerinci volcano. Rinjani has a steep-sided conical profile when viewed from the E, but the W side of the compound volcano is truncated by the 6 x 8.5 km, oval-shaped Segara Anak caldera. The western half of the caldera contains a 230-m-deep lake whose crescentic form results from growth of the post-caldera cone Barujari at the E end of the caldera. Historical eruptions at Rinjani dating back to 1847 have been restricted to Barujari cone and consist of moderate explosive activity and occasional lava flows that have entered Segara Anak lake.
Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://www.vsi.esdm.go.id/
SAKURA-JIMA Kyushu 31.585°N, 130.657°E; summit elev. 1117 m
Based on information from JMA and pilot observations, the Tokyo VAAC reported that during 17, 19-21, and 23 November ash plumes from Sakura-jima rose to altitudes of 1.2-3 km (4,000-10,000 ft) a.s.l. and drifted E, NE, and 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
SANTA MARIA Guatemala 14.756°N, 91.552°W; summit elev. 3772 m
INSIVUMEH reported that on 17 and 22 November explosions from Santa María's Santiaguito lava dome complex produced ash plumes that rose 0.7-1 km above the crater and drifted E and SW, respectively. On 19 November cloud cover prevented observations of the volcano. Ashfall was reported from farms to the S.
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.
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH) http://www.insivumeh.gob.gt/
SUWANOSE-JIMA Ryukyu Islands (Japan) 29.635°N, 129.716°E; summit elev. 799 m
Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima during 18-23 November. Plumes rose to an altitude of 1.8 km (6,000 ft) on 18 November and to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted NE on 21 November.
Geologic Summary. The 8-km-long, spindle-shaped island of Suwanose-jima in the northern Ryukyu Islands consists of an andesitic stratovolcano with two historically active summit craters. Only about 50 persons live on the sparsely populated island. The summit of the volcano is truncated by a large breached crater extending to the sea on the east flank that was formed by edifice collapse. Suwanose-jima, one of Japan's most frequently active volcanoes, was in a state of intermittent Strombolian activity from On-take, the NE summit crater, that began in 1949 and lasted nearly a half century. The largest historical eruption took place in 1813-14, when thick scoria deposits blanketed residential areas, after which the island was uninhabited for about 70 years. The SW crater produced lava flows that reached the western coast in 1813, and lava flows reached the eastern coast of the island in 1884.
Source: Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html
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