VOLCANO: Smithsonian/USGS Weekly Volcanic Activity Report 9-15 February 2011
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Smithsonian/USGS Weekly Volcanic Activity Report 9-15 February 2011
Smithsonian/USGS Weekly Volcanic Activity Report
9-15 February 2011
Sally Kuhn Sennert - Weekly Report Editor
New Activity/Unrest: | Fuego, Guatemala | Kirishima, Kyushu | Santa María, Guatemala
Ongoing Activity: | Dukono, Halmahera | Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaii (USA) | Kizimen, Eastern Kamchatka (Russia) | Kliuchevskoi, Central Kamchatka (Russia) | Poás, Costa Rica | Sakura-jima, Kyushu | Shiveluch, Central Kamchatka (Russia) | Soufrière Hills, Montserrat | St. Helens, Washington (USA) | Suwanose-jima, Ryukyu Islands (Japan) | Tengger Caldera, Eastern Java (Indonesia)
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.
FUEGO Guatemala 14.473°N, 90.880°W; summit elev. 3763 m
INSIVUMEH reported that during 9-10 and 13-14 February explosions from Fuego produced ash plumes that rose 300-800 m above the crater and drifted W, NW, N, and NE. The explosions generated shock waves that rattled structures in Panimaché and Sangre de Cristo. Crater incandescence was observed at night and avalanches descended the flanks. Fine ashfall was reported in communities downwind during 9-10 February, including Panimaché I and II (8 km SW), Morelia (9 km SW), and Sangre de Cristo (8 km WSW).
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.
KIRISHIMA Kyushu 31.931°N, 130.864°E; summit elev. 1700 m
Based on reports from JMA, the Tokyo VAAC reported that during 9-11 February explosions from Shinmoe-dake (Shinmoe peak), a stratovolcano of the Kirishima volcano group, produced plumes that rose to altitudes of 1.8-4 km (6,000-13,000 ft) a.s.l. and drifted E and SE. On 11 and 14 February, pilots observed ash plumes that rose to altitudes of 4.6-6.1 km (15,000-20,000 ft) a.s.l. According to a news article, rocks ejected during an eruption on 14 February broke windows in cars parked at the Kirishima service area on the Miyazaki expressway and in several places in Kobayashi, 13 km NE.
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.
SANTA MARIA Guatemala 14.756°N, 91.552°W; summit elev. 3772 m
Based on information from INSIVUMEH, the Washington VAAC reported that ash observed in satellite imagery from a pyroclastic flow at Santa María's Santiaguito lava dome complex on 9 February had dissipated. INSIVUMEH reported that early on 10 February explosions produced ash plumes that rose almost 800 m above Caliente dome. Cloud cover prevented observations through the day. Seismic data suggested a block avalanche at 1230. During 11-12 February ash from pyroclastic flows was detected in satellite imagery and rose to altitudes of 3.4-4.3 km (11,000-14,000 ft) a.s.l. On 13 February INSIVUMEH noted that a pyroclastic flow was detected, but not visually observed due to cloud cover. Explosions during 13-15 February produced ash plumes that rose 300-1,200 m above the dome. Block avalanches originated from the E crater rim. Ash fell in the La Florida and El Faro fincas (ranches) 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.
DUKONO Halmahera 1.68°N, 127.88°E; summit elev. 1335 m
Based on analyses of satellite imagery, the Darwin VAAC reported that on 11 February an ash plume from Dukono rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted 75 km N.
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.
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 4-11 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 160 km E during 6-7 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.
KILAUEA Hawaii (USA) 19.421°N, 155.287°W; summit elev. 1222 m
During 9-15 February, activity continued from the summit caldera and east rift zone. At the summit caldera, the level of the lava-pool surface in the deep pit within Halema'uma'u crater circulated and periodically changed depth. The highest level the lava rose to 72 m below the crater floor. Nighttime incandescence was visible from the Jaggar Museum on the NW caldera rim. A plume from the vent drifted mostly W and deposited ash and fresh spatter nearby.
At the east rift zone, lava flows continued from one of the upper rootless shields, near the TEB vent. Two branches of the 29 November lava flow (a lava tube breach at 366 m elevation) produced scattered surface flows on the pali and coastal plain. In Pu'u 'O'o crater, incandescence emanated from a cone on the N portion of the crater floor, lava effused from a cone on the W edge of the floor, and spatter and lava flows were produced from a vent in the E crater wall. On 12 February increased activity from a cone on the N floor was characterized by lava flows and incandescent tephra ejected 40-50 m above the cone. During 14-15 February lava from a NE cone covered the E half of the 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.
KIZIMEN Eastern Kamchatka (Russia) 55.130°N, 160.32°E; summit elev. 2376 m
KVERT reported that during 4-11 February seismicity from Kizimen was high but variable, and many shallow volcanic earthquakes as well as volcanic tremor continued to be detected. Ash plumes drifted more than 260 km E. Satellite images during 4-14 February showed a bright daily thermal anomaly over the volcano. On 14 February the magnitude of volcanic tremor gradually increased and resembled seismic patterns noted on 8 December, a few days before strong ash explosions occurred. The Aviation Color Code remained at Orange.
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.
KLIUCHEVSKOI Central Kamchatka (Russia) 56.057°N, 160.638°E; summit elev. 4835 m
Although moderate seismic activity was recorded at Kliuchevskoi during 4-11 February, KVERT reported that seismicity had essentially decreased. Gas-and-steam activity was observed during 4-7 February; clouds prevented observations on later days. Gas-and-steam plumes drifted 20 km NE on 5 and 7 February. Satellite imagery showed a weak thermal anomaly over the crater on 6 and 7 February. The Aviation Color Code was lowered to Green.
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.
POAS Costa Rica 10.20°N, 84.233°W; summit elev. 2708 m
OVSICORI-UNA reported that on 2 February a small phreatic eruption occurred from the central part of Laguna Caliente, a summit lake of Poás. Solid dark material was ejected 6 m high and fell back into the lake. Before, during, and after the eruption a concentric area of the lake surface about 15 m in diameter was disturbed by a convecting cell. Bubbles of gas rose from the agitated area and upwelling sediments were observed.
Geologic Summary. The broad, well-vegetated edifice of Poás, one of the most active volcanoes of Costa Rica, contains three craters along a N-S line. The frequently visited multi-hued summit crater lakes of the basaltic-to-dacitic volcano, which is one of Costa Rica's most prominent natural landmarks, are easily accessible by vehicle from the nearby capital city of San José. A N-S-trending fissure cutting the 2,708-m-high complex stratovolcano extends to the lower northern flank, where it has produced the Congo stratovolcano and several lake-filled maars. The southernmost of the two summit crater lakes, Botos, is cold and clear and last erupted about 7,500 years ago. The more prominent geothermally heated northern lake, Laguna Caliente, is one of the world's most acidic natural lakes, with a pH of near zero. It has been the site of frequent phreatic and phreatomagmatic eruptions since the first historical eruption was reported in 1828. Poás eruptions often include geyser-like ejection of crater-lake water.
SAKURA-JIMA Kyushu 31.585°N, 130.657°E; summit elev. 1117 m
Based on information from JMA, the Tokyo VAAC reported that during 9 and 11-15 February explosions from Sakura-jima sometimes produced plumes that rose to altitudes of 1.5-2.1 km (5,000-7,000 ft) a.s.l. and drifted S, SE, and E. On 10, 13, and 15 February, pilots reported that ash plumes rose to altitudes of 1.8-3 km (6,000-10,000 ft) a.s.l.
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.
SHIVELUCH Central Kamchatka (Russia) 56.653°N, 161.360°E; summit elev. 3283 m
KVERT reported that moderate seismic activity was recorded at Shiveluch during 4-11 February and many volcanic earthquakes were detected. A thermal anomaly over the lava dome was observed in satellite imagery. Ash plumes observed from the ground rose to an altitude of 7.5 km (24,600 ft) a.s.l. on 4 February. That same day ash plumes detected in satellite imagery drifted 120 km E. Gas-and-steam activity was observed during 4 and 6-7 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.
SOUFRIERE HILLS Montserrat 16.72°N, 62.18°W; summit elev. 915 m
MVO reported that during 4-11 February activity from the Soufrière Hills lava dome was at a low level. Helicopter observations revealed fresh pyroclastic-flow deposits about 1.5 km long in the Tar River valley to the E that formed on 10 February. The pyroclastic flow had an extensive surge component that inundated the lower flanks of Roaches Mountain. Clouds prevented observations of the lava dome. 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.
ST. HELENS Washington (USA) 46.20°N, 122.18°W; summit elev. 2549 m
CVO reported that on 14 February a M 4.3 earthquake near Mount St. Helens, felt widely throughout SW Washington and NW Oregon, was followed over the next few hours by several aftershocks up to M 2.8. The three largest aftershocks were also felt. All of the earthquakes were located about 8 km N of the crater, near the Johnston Ridge Observatory, at depths of about 4-6 km. CVO also noted that a previous earthquake swarm had occurred in the same area on 29 January. The Volcano Alert Level remained at Normal and the Aviation Color Code remained at Green.
Geologic Summary. Prior to 1980, Mount St. Helens formed a conical, youthful volcano sometimes known as the Fuji-san of America. During the 1980 eruption the upper 400 m of the summit was removed by slope failure, leaving a 2 x 3.5 km horseshoe-shaped crater now partially filled by a lava dome. Mount St. Helens was formed during nine eruptive periods beginning about 40-50,000 years ago, and has been the most active volcano in the Cascade Range during the Holocene. The modern edifice was constructed during the last 2,200 years, when the volcano produced basaltic as well as andesitic and dacitic products from summit and flank vents. Historical eruptions in the 19th century originated from the Goat Rocks area on the N flank, and were witnessed by early settlers.
SUWANOSE-JIMA Ryukyu Islands (Japan) 29.635°N, 129.716°E; summit elev. 799 m
Based on information from JMA, the Tokyo VAAC reported an explosion from Suwanose-jima on 9 and 14 February. Details of a possible resulting plume were not reported.
Geologic Summary. The 8-km-long, spindle-shaped island of Suwanose-jima in the northern Ryukyu Islands consists of an andesitic stratovolcano with two historically active summit craters. Only about 50 persons live on the sparsely populated island. The summit of the volcano is truncated by a large breached crater extending to the sea on the east flank that was formed by edifice collapse. Suwanose-jima, one of Japan's most frequently active volcanoes, was in a state of intermittent Strombolian activity from On-take, the NE summit crater, that began in 1949 and lasted nearly a half century. The largest historical eruption took place in 1813-14, when thick scoria deposits blanketed residential areas, after which the island was uninhabited for about 70 years. The SW crater produced lava flows that reached the western coast in 1813, and lava flows reached the eastern coast of the island in 1884.
TENGGER CALDERA Eastern Java (Indonesia) 7.942°S, 112.95°E; summit elev. 2329 m
CVGHM reported that during 8-9 February gray-to-brown ash plumes from Tengger Caldera's Bromo cone rose 400-800 m above the crater and drifted E. Incandescent material was ejected 300 m above the crater and landed as far as 500 m away, and roaring and booming was heard. Ash fell at the Bromo observation post on 8 February. The Alert Level remained at 3 (on a scale of 1-4). Residents and tourists were not permitted within a 2-km-radius of the active crater.
Based on a pilot observation, the Darwin VAAC reported that on 9 February an eruption produced a plume that rose to an altitude of 7 km (23,000 ft) a.s.l. and drifted W. On 11 February satellite imagery showed an ash plume drifting 37 km SE at an altitude of 3 km (10,000 ft) a.s.l. Ash plumes on 12 February rose to altitudes of 3-7.9 km (10,000-26,000 ft) a.s.l. and drifted 37-167 km NW and SE.
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.
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