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Smithsonian/USGS Weekly Volcanic Activity Report 23 February-1 March 2011
From: "Kuhn, Sally" <KUHNS@xxxxxx>
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Smithsonian/USGS Weekly Volcanic Activity Report
23 February-1 March 2011
Sally Kuhn Sennert - Weekly Report Editor
kuhns@xxxxxx
URL: http://www.volcano.si.edu/reports/usgs/
New Activity/Unrest: | Fuego, Guatemala | Lokon-Empung, Sulawesi | Santa María, Guatemala | Ulawun, New Britain
Ongoing Activity: | Bulusan, Luzon | Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaii (USA) | Kirishima, Kyushu | Kizimen, Eastern Kamchatka (Russia) | Pagan, Mariana Islands (Central Pacific) | Sakura-jima, Kyushu | Sangay, Ecuador | Shiveluch, Central Kamchatka (Russia) | Soufrière Hills, Montserrat
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
FUEGO Guatemala 14.473°N, 90.880°W; summit elev. 3763 m
INSIVUMEH reported that during 24-25 and 27-28 February explosions from Fuego produced ash plumes that rose 500-700 m above the crater and drifted W and SW. Incandescent material was ejected as high as 100 m above the crater. Avalanches traveled SW, descending the Taniluyá, Ceniza, and Trinidad drainages.
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/
LOKON-EMPUNG Sulawesi 1.358°N, 124.792°E; summit elev. 1580 m
According to news articles, a phreatic eruption from Tompaluan crater, in the saddle between the Lokon-Empung peaks, produced an ash plume that rose 400 m above the crater rim and drifted SE on 22 February.
Geologic Summary. The twin volcanoes Lokon and Empung, rising about 800 m above the plain of Tondano, are among the most active volcanoes of Sulawesi. Lokon, the higher of the two peaks (whose summits are only 2.2 km apart) has a flat, craterless top. The morphologically younger Empung volcano has a 400-m-wide, 150-m-deep crater that erupted last in the 18th century, but all subsequent eruptions have originated from Tompaluan, a 150 x 250 m wide double crater situated in the saddle between the two peaks. Historical eruptions have primarily produced small-to-moderate ash plumes that have occasionally damaged croplands and houses, but lava-dome growth and pyroclastic flows have also occurred.
Source: Tempo http://www.tempointeraktif.com/hg/nusa_lainnya/2011/02/23/brk,20110223-315501,id.html
SANTA MARIA Guatemala 14.756°N, 91.552°W; summit elev. 3772 m
INSIVUMEH reported that during 24-25 February a few explosions from Santa María's Santiaguito lava dome complex produced ash plumes that rose 800 m above Caliente dome and drifted SW. Incandescent avalanches descended the E and SW flanks.
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/
ULAWUN New Britain 5.05°S, 151.33°E; summit elev. 2334 m
RVO reported that mild activity from Ulawun that began in May 2010 continued during 1 January-28 February. The activity was characterized by brown-to-gray ash plumes that rose less than 500 m and produced fine ashfall to the SE. Sulfur dioxide plumes drifted SE on 5 and 31 January. During 23-26 February gray ash plumes occasionally drifted NE, SW, and NW.
Geologic Summary. The symmetrical basaltic to andesitic Ulawun stratovolcano is the highest volcano of the Bismarck arc, and one of Papua New Guinea's most frequently active. Ulawun rises above the N coast of New Britain opposite Bamus volcano. The upper 1,000 m of the 2,334-m-high volcano is unvegetated. A steep-walled valley cuts the NW side of the volcano, and a flank lava-flow complex lies to the S of this valley. Historical eruptions date back to the beginning of the 18th century. Twentieth-century eruptions were mildly explosive until 1967, but after 1970 several larger eruptions produced lava flows and basaltic pyroclastic flows, greatly modifying the summit crater.
Source: Rabaul Volcano Observatory (RVO)
Ongoing Activity
BULUSAN Luzon 12.770°N, 124.05°E; summit elev. 1565 m
During 24 February-1 March, PHIVOLCS reported that up to five daily volcanic earthquakes at Bulusan were detected by the seismic network. There were 13 lahar-related seismic signals detected during 27-28 February. Continuous heavy rain caused small lahars on the flanks and in river channels, including the Cogon and Monbon rivers to the SW. Cloud cover prevented observations of the summit area during 24-28 February.
Based on notices from the Manila airport (RPLL), the Tokyo VAAC reported that on 24 and 28 February ash was observed. However, ash was not identified in satellite imagery.
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/index.php,
Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html
KARYMSKY Eastern Kamchatka (Russia) 54.05°N, 159.45°E; summit elev. 1536 m
KVERT reported that moderate seismic activity was detected at Karymsky during 18-25 February. Seismic data indicated that possible ash plumes rose to an altitude of 4 km (13,100 ft) a.s.l. Satellite imagery showed a daily thermal anomaly and ash plumes that drifted 38 km NE on 22 February. The Aviation Color Code remained at Orange.
Geologic Summary. Karymsky, the most active volcano of Kamchatka's eastern volcanic zone, is a symmetrical stratovolcano constructed within a 5-km-wide caldera that formed about 7,600-7,700 radiocarbon years ago. Construction of the Karymsky stratovolcano began about 2,000 years later. The latest eruptive period began about 500 years ago, following a 2,300-year quiescence. Much of the cone is mantled by lava flows less than 200 years old. Historical eruptions have been Vulcanian or Vulcanian-Strombolian with moderate explosive activity and occasional lava flows from the summit crater. Most seismicity preceding Karymsky eruptions has originated beneath Akademia Nauk caldera, which is located immediately S of Karymsky volcano and erupted simultaneously with Karymsky in 1996.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/current/shv/index.html
KILAUEA Hawaii (USA) 19.421°N, 155.287°W; summit elev. 1222 m
During 23 February-2 March, activity continued from the summit caldera and east rift zone. At the summit caldera, the level of the circulating lava-pool surface in the deep pit within Halema'uma'u crater fluctuated between 80 and 120 m below the crater floor. Nighttime incandescence was visible from the Jaggar Museum on the NW caldera rim. A plume from the vent drifted in multiple directions and deposited ash and fresh spatter nearby. At the east rift zone, two branches of the 29 November lava flow (from a lava tube breach at 366 m elevation) produced scattered surface flows on the pali and coastal plain. In Pu'u 'O'o crater, lava periodically effused or spattered from a cone on the NE portion of the crater floor and from a vent in the E crater wall.
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/
KIRISHIMA Kyushu 31.931°N, 130.864°E; summit elev. 1700 m
Based on reports from JMA, the Tokyo VAAC reported that eruptions from Kirishima’s Shinmoe-dake (Shinmoe peak) on 24 and 28 February as well as 1 March produced plumes that rose to altitudes of 1.8-2.1 km (6,000-7,000 ft) a.s.l. and drifted N, E, and SE.
Geologic Summary. Kirishima is a large group of more than 20 Quaternary volcanoes located north of Kagoshima Bay. The late-Pleistocene to Holocene volcano group consists of stratovolcanoes, pyroclastic cones, maars, and underlying shield volcanoes located over an area of 20 x 30 km. The larger stratovolcanoes are scattered throughout the field, with the centrally located, 1,700-m-high Karakuni-dake being the highest. Onami-ike and Mi-ike, the two largest maars, are located SW of Karakuni-dake and at its far eastern end, respectively. Holocene eruptions have been concentrated along an E-W line of vents from Mi-ike to Ohachi, and at Shinmoe-dake to the NE. Frequent small-to-moderate explosive eruptions have been recorded since the 8th century.
Source: Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html
KIZIMEN Eastern Kamchatka (Russia) 55.130°N, 160.32°E; summit elev. 2376 m
KVERT reported that during 18-21 February seismicity from Kizimen was high but variable, and many shallow volcanic earthquakes as well as volcanic tremor continued to be detected. Satellite images showed a bright thermal anomaly over the volcano daily during 18-25 February. Ash plumes drifted more than 200 km E during 21-24 February. The Aviation Color Code remained at Orange.
The Tokyo VAAC reported that on 25 February an eruption detected in satellite imagery produced a plume that rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted E. Subsequent notices stated that continuing ash emissions dissipated later that day. NASA's Earth Observatory posted a satellite image acquired on 25 February that showed steam and ash plumes drifting NE. Ash on the snow was visible NE, E, and SE of the volcano. The VAAC also noted that eruptions reported by KEMSD during 27 February-1 March produced plumes that rose to altitudes of 6.1-7.3 km (20,000-24,000 ft) a.s.l.
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.
Sources: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/current/shv/index.html,
Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html,
NASA Earth Observatory http://earthobservatory.nasa.gov/
PAGAN Mariana Islands (Central Pacific) 18.13°N, 145.80°E; summit elev. 570 m
On 22 February, the Aviation Color Code and the Volcano Alert Level for Pagan were lowered to Unassigned. With the exception of a faint steam-and-gas plume observed on 24 January, no unusual activity at Pagan volcano had been detected in satellite imagery during the previous six weeks. Pagan is not monitored with ground-based geophysical instrumentation; the only source of information is satellite observations and occasional reports from island visitors.
Geologic Summary. Pagan Island, the largest and one of the most active of the Mariana 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 during 23 February-2 March explosions from Sakura-jima sometimes produced plumes that rose to altitudes of 1.5-2.7 km (5,000-9,000 ft) a.s.l. and drifted in multiple directions. On 23 and 26 February, pilots reported that ash plumes rose to altitudes of 3 and 4 km (10,000 and 13,000 ft) a.s.l. and drifted E and NW, respectively.
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 23 February a pilot observed ash from Sangay. No ash was confirmed in a small cloud identified in satellite imagery drifting SSE.
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 moderate seismic activity was detected at Shiveluch during 18-25 February. A thermal anomaly over the lava dome was observed daily in satellite imagery. Gas and steam activity was observed during 21-24 February and ash plumes rose to an altitude of 5.5 km (18,000 ft) a.s.l. during 22-23 February. Ash plumes observed in satellite imagery drifted more than 220 km SE at altitudes below 6 km (19,700 ft) a.s.l. during 23-24 February. The Aviation 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/current/shv/index.html
SOUFRIERE HILLS Montserrat 16.72°N, 62.18°W; summit elev. 915 m
MVO reported that during 18-25 February activity from the Soufrière Hills lava dome was at a low level. Of 31 volcano-tectonic earthquakes detected by the seismic network, 18 occurred in a small swarm on 23 February. On 24 February a pyroclastic flow that traveled less than 1.5 km on the N flank originated from one of the highest parts of the dome, and travelled down the collapse scar formed on 11 February. The event produced an extensive pyroclastic surge and a relatively strong ash plume that rose to an altitude of about 1.5 km (5,000 ft) a.s.l. 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/
==============================================================
23 February-1 March 2011
Sally Kuhn Sennert - Weekly Report Editor
kuhns@xxxxxx
URL: http://www.volcano.si.edu/reports/usgs/
New Activity/Unrest: | Fuego, Guatemala | Lokon-Empung, Sulawesi | Santa María, Guatemala | Ulawun, New Britain
Ongoing Activity: | Bulusan, Luzon | Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaii (USA) | Kirishima, Kyushu | Kizimen, Eastern Kamchatka (Russia) | Pagan, Mariana Islands (Central Pacific) | Sakura-jima, Kyushu | Sangay, Ecuador | Shiveluch, Central Kamchatka (Russia) | Soufrière Hills, Montserrat
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
FUEGO Guatemala 14.473°N, 90.880°W; summit elev. 3763 m
INSIVUMEH reported that during 24-25 and 27-28 February explosions from Fuego produced ash plumes that rose 500-700 m above the crater and drifted W and SW. Incandescent material was ejected as high as 100 m above the crater. Avalanches traveled SW, descending the Taniluyá, Ceniza, and Trinidad drainages.
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/
LOKON-EMPUNG Sulawesi 1.358°N, 124.792°E; summit elev. 1580 m
According to news articles, a phreatic eruption from Tompaluan crater, in the saddle between the Lokon-Empung peaks, produced an ash plume that rose 400 m above the crater rim and drifted SE on 22 February.
Geologic Summary. The twin volcanoes Lokon and Empung, rising about 800 m above the plain of Tondano, are among the most active volcanoes of Sulawesi. Lokon, the higher of the two peaks (whose summits are only 2.2 km apart) has a flat, craterless top. The morphologically younger Empung volcano has a 400-m-wide, 150-m-deep crater that erupted last in the 18th century, but all subsequent eruptions have originated from Tompaluan, a 150 x 250 m wide double crater situated in the saddle between the two peaks. Historical eruptions have primarily produced small-to-moderate ash plumes that have occasionally damaged croplands and houses, but lava-dome growth and pyroclastic flows have also occurred.
Source: Tempo http://www.tempointeraktif.com/hg/nusa_lainnya/2011/02/23/brk,20110223-315501,id.html
SANTA MARIA Guatemala 14.756°N, 91.552°W; summit elev. 3772 m
INSIVUMEH reported that during 24-25 February a few explosions from Santa María's Santiaguito lava dome complex produced ash plumes that rose 800 m above Caliente dome and drifted SW. Incandescent avalanches descended the E and SW flanks.
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/
ULAWUN New Britain 5.05°S, 151.33°E; summit elev. 2334 m
RVO reported that mild activity from Ulawun that began in May 2010 continued during 1 January-28 February. The activity was characterized by brown-to-gray ash plumes that rose less than 500 m and produced fine ashfall to the SE. Sulfur dioxide plumes drifted SE on 5 and 31 January. During 23-26 February gray ash plumes occasionally drifted NE, SW, and NW.
Geologic Summary. The symmetrical basaltic to andesitic Ulawun stratovolcano is the highest volcano of the Bismarck arc, and one of Papua New Guinea's most frequently active. Ulawun rises above the N coast of New Britain opposite Bamus volcano. The upper 1,000 m of the 2,334-m-high volcano is unvegetated. A steep-walled valley cuts the NW side of the volcano, and a flank lava-flow complex lies to the S of this valley. Historical eruptions date back to the beginning of the 18th century. Twentieth-century eruptions were mildly explosive until 1967, but after 1970 several larger eruptions produced lava flows and basaltic pyroclastic flows, greatly modifying the summit crater.
Source: Rabaul Volcano Observatory (RVO)
Ongoing Activity
BULUSAN Luzon 12.770°N, 124.05°E; summit elev. 1565 m
During 24 February-1 March, PHIVOLCS reported that up to five daily volcanic earthquakes at Bulusan were detected by the seismic network. There were 13 lahar-related seismic signals detected during 27-28 February. Continuous heavy rain caused small lahars on the flanks and in river channels, including the Cogon and Monbon rivers to the SW. Cloud cover prevented observations of the summit area during 24-28 February.
Based on notices from the Manila airport (RPLL), the Tokyo VAAC reported that on 24 and 28 February ash was observed. However, ash was not identified in satellite imagery.
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/index.php,
Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html
KARYMSKY Eastern Kamchatka (Russia) 54.05°N, 159.45°E; summit elev. 1536 m
KVERT reported that moderate seismic activity was detected at Karymsky during 18-25 February. Seismic data indicated that possible ash plumes rose to an altitude of 4 km (13,100 ft) a.s.l. Satellite imagery showed a daily thermal anomaly and ash plumes that drifted 38 km NE on 22 February. The Aviation Color Code remained at Orange.
Geologic Summary. Karymsky, the most active volcano of Kamchatka's eastern volcanic zone, is a symmetrical stratovolcano constructed within a 5-km-wide caldera that formed about 7,600-7,700 radiocarbon years ago. Construction of the Karymsky stratovolcano began about 2,000 years later. The latest eruptive period began about 500 years ago, following a 2,300-year quiescence. Much of the cone is mantled by lava flows less than 200 years old. Historical eruptions have been Vulcanian or Vulcanian-Strombolian with moderate explosive activity and occasional lava flows from the summit crater. Most seismicity preceding Karymsky eruptions has originated beneath Akademia Nauk caldera, which is located immediately S of Karymsky volcano and erupted simultaneously with Karymsky in 1996.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/current/shv/index.html
KILAUEA Hawaii (USA) 19.421°N, 155.287°W; summit elev. 1222 m
During 23 February-2 March, activity continued from the summit caldera and east rift zone. At the summit caldera, the level of the circulating lava-pool surface in the deep pit within Halema'uma'u crater fluctuated between 80 and 120 m below the crater floor. Nighttime incandescence was visible from the Jaggar Museum on the NW caldera rim. A plume from the vent drifted in multiple directions and deposited ash and fresh spatter nearby. At the east rift zone, two branches of the 29 November lava flow (from a lava tube breach at 366 m elevation) produced scattered surface flows on the pali and coastal plain. In Pu'u 'O'o crater, lava periodically effused or spattered from a cone on the NE portion of the crater floor and from a vent in the E crater wall.
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/
KIRISHIMA Kyushu 31.931°N, 130.864°E; summit elev. 1700 m
Based on reports from JMA, the Tokyo VAAC reported that eruptions from Kirishima’s Shinmoe-dake (Shinmoe peak) on 24 and 28 February as well as 1 March produced plumes that rose to altitudes of 1.8-2.1 km (6,000-7,000 ft) a.s.l. and drifted N, E, and SE.
Geologic Summary. Kirishima is a large group of more than 20 Quaternary volcanoes located north of Kagoshima Bay. The late-Pleistocene to Holocene volcano group consists of stratovolcanoes, pyroclastic cones, maars, and underlying shield volcanoes located over an area of 20 x 30 km. The larger stratovolcanoes are scattered throughout the field, with the centrally located, 1,700-m-high Karakuni-dake being the highest. Onami-ike and Mi-ike, the two largest maars, are located SW of Karakuni-dake and at its far eastern end, respectively. Holocene eruptions have been concentrated along an E-W line of vents from Mi-ike to Ohachi, and at Shinmoe-dake to the NE. Frequent small-to-moderate explosive eruptions have been recorded since the 8th century.
Source: Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html
KIZIMEN Eastern Kamchatka (Russia) 55.130°N, 160.32°E; summit elev. 2376 m
KVERT reported that during 18-21 February seismicity from Kizimen was high but variable, and many shallow volcanic earthquakes as well as volcanic tremor continued to be detected. Satellite images showed a bright thermal anomaly over the volcano daily during 18-25 February. Ash plumes drifted more than 200 km E during 21-24 February. The Aviation Color Code remained at Orange.
The Tokyo VAAC reported that on 25 February an eruption detected in satellite imagery produced a plume that rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted E. Subsequent notices stated that continuing ash emissions dissipated later that day. NASA's Earth Observatory posted a satellite image acquired on 25 February that showed steam and ash plumes drifting NE. Ash on the snow was visible NE, E, and SE of the volcano. The VAAC also noted that eruptions reported by KEMSD during 27 February-1 March produced plumes that rose to altitudes of 6.1-7.3 km (20,000-24,000 ft) a.s.l.
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.
Sources: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/current/shv/index.html,
Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html,
NASA Earth Observatory http://earthobservatory.nasa.gov/
PAGAN Mariana Islands (Central Pacific) 18.13°N, 145.80°E; summit elev. 570 m
On 22 February, the Aviation Color Code and the Volcano Alert Level for Pagan were lowered to Unassigned. With the exception of a faint steam-and-gas plume observed on 24 January, no unusual activity at Pagan volcano had been detected in satellite imagery during the previous six weeks. Pagan is not monitored with ground-based geophysical instrumentation; the only source of information is satellite observations and occasional reports from island visitors.
Geologic Summary. Pagan Island, the largest and one of the most active of the Mariana 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 during 23 February-2 March explosions from Sakura-jima sometimes produced plumes that rose to altitudes of 1.5-2.7 km (5,000-9,000 ft) a.s.l. and drifted in multiple directions. On 23 and 26 February, pilots reported that ash plumes rose to altitudes of 3 and 4 km (10,000 and 13,000 ft) a.s.l. and drifted E and NW, respectively.
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 23 February a pilot observed ash from Sangay. No ash was confirmed in a small cloud identified in satellite imagery drifting SSE.
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 moderate seismic activity was detected at Shiveluch during 18-25 February. A thermal anomaly over the lava dome was observed daily in satellite imagery. Gas and steam activity was observed during 21-24 February and ash plumes rose to an altitude of 5.5 km (18,000 ft) a.s.l. during 22-23 February. Ash plumes observed in satellite imagery drifted more than 220 km SE at altitudes below 6 km (19,700 ft) a.s.l. during 23-24 February. The Aviation 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/current/shv/index.html
SOUFRIERE HILLS Montserrat 16.72°N, 62.18°W; summit elev. 915 m
MVO reported that during 18-25 February activity from the Soufrière Hills lava dome was at a low level. Of 31 volcano-tectonic earthquakes detected by the seismic network, 18 occurred in a small swarm on 23 February. On 24 February a pyroclastic flow that traveled less than 1.5 km on the N flank originated from one of the highest parts of the dome, and travelled down the collapse scar formed on 11 February. The event produced an extensive pyroclastic surge and a relatively strong ash plume that rose to an altitude of about 1.5 km (5,000 ft) a.s.l. 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/
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