*************************************************************** SI/USGS Weekly Volcanic Activity Report 25 February-3 March 2009 *************************************************************** Sally Kuhn Sennert - Weekly Report Editor kuhns@xxxxxx URL: http://www.volcano.si.edu/reports/usgs/ New Activity/Unrest: | Chaitén, Southern Chile | Koryaksky, Eastern Kamchatka | Okmok, Fox Islands | Sakura-jima, Kyushu Ongoing Activity: | Colima, México | Galeras, Colombia | Karymsky, Eastern Kamchatka | Kilauea, Hawaii (USA) | Redoubt, Southwestern Alaska | Santa María, Guatemala | Shiveluch, Central Kamchatka (Russia) | Soufrière Hills, Montserrat | Suwanose-jima, Ryukyu Islands (Japan) | Tungurahua, Ecuador 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 CHAITEN Southern Chile 42.833°S, 72.646°W; summit elev. 1122 m On 24 February, SERNAGEOMIN reported that an overflight of Chaitén's Domo Nuevo 1 and Domo Nuevo 2 lava-dome complex revealed that a large amount of material from the 19 February partial dome collapse had accumulated in the basal ring depression surrounding the dome complex and throughout the Chaitén (Blanco) River valley. Most of the collapsed material originated from Domo Nuevo 1. Steam plumes with little ash content rose from the N part of Domo Nuevo 2 and steam and brown ash plumes were emitted from a central spine complex. Steam plumes and sporadic explosions were noted from the S part of Domo Nuevo 1; producing four plumes that mixed and rose 1.5 km above the complex. Small collapses, originating from unstable slopes of the SE part of Domo Nuevo 1, generated block-and-ash flows. On 26 February, observers in Chaitén town (10 km SW) reported that plumes rose 2 km above the complex. During 26-27 February, small collapses caused the plume to occasionally enlarge and turn brown. On 27 February, an overflight revealed that the S part of Domo Nuevo 1 continued to grow. Numerous fan-shaped deposits from collapses were seen on the S slope. Based on web camera views, the Buenos Aires VAAC reported that during 27 February, and 2-3 March plumes rose to altitudes of 2.1-2.4 km (7,000-8,000 ft) a.s.l. Plumes drifted E on 27 February and SE on 3 March. Geologic Summary. Chaitén is a small, glacier-free caldera with a Holocene lava dome located 10 km NE of the town of Chaitén on the Gulf of Corcovado. A pyroclastic-surge and pumice deposit considered to originate from the eruption that formed the elliptical 2.5 x 4 km wide summit caldera was dated at about 9400 years ago. A rhyolitic, 962-m-high obsidian lava dome occupies much of the caldera floor. Obsidian cobbles from this dome found in the Blanco River are the source of prehistorical artifacts from archaeological sites along the Pacific coast as far as 400 km away from the volcano to the north and south. The caldera is breached on the SW side by a river that drains to the bay of Chaitén, and the high point on its southern rim reaches 1122 m. Sources: Servicio Nacional de Geología y Minería (SERNAGEOMIN) http://www.sernageomin.cl/index.php, Buenos Aires Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AG/messages.html KORYAKSKY Eastern Kamchatka 53.320°N, 158.688°E; summit elev. 3456 m KVERT reported that during 25 February-4 March seismic activity at Koryaksky was at background levels. Observers reported that during 3-4 March gas plumes containing a small amount of ash rose to an altitude of 3.7 km (12,100 ft) a.s.l. and drifted more than 200 km ENE. Ash deposits were seen at the summit. Ash deposits 1-2 mm thick accumulated in an area between Koryaksky and Avachinsky volcanoes. The Level of Concern Color Code was raised to Orange. Geologic Summary. The large symmetrical Koryaksky stratovolcano is the most prominent landmark of the NW-trending Avachinskaya volcano group, which towers above Kamchatka's largest city, Petropavlovsk. Erosion has produced a ribbed surface on the eastern flanks of the 3456-m-high volcano; the youngest lava flows are found on the upper western flank and below SE-flank cinder cones. No strong explosive eruptions have been documented during the Holocene. Extensive Holocene lava fields on the western flank were primarily fed by summit vents; those on the SW flank originated from flank vents. Lahars associated with a period of lava effusion from south- and SW-flank fissure vents about 3900-3500 years ago reached Avacha Bay. Only a few moderate explosive eruptions have occurred during historical time. Koryaksky's first historical eruption, in 1895, also produced a lava flow. Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php OKMOK Fox Islands 53.43°N, 168.13°W; summit elev. 1073 m On 2 March, AVO raised the Volcano Alert Level for Okmok to Advisory and the Aviation Color Code to Yellow because of increased seismicity. Short bursts of volcanic tremor at an average rate of one per hour had been detected during the previous 24 hours, an increase above the typical background level. The events were the first sign of significant seismic activity at the volcano since the cessation of the last eruption in August 2008. Geologic Summary. The broad, basaltic Okmok shield volcano, which forms the NE end of Umnak Island, has a dramatically different profile than most other Aleutian volcanoes. The summit of the low, 35-km-wide volcano is cut by two 10-km-wide calderas formed during eruptions about 8,250 and 2,400 years ago that produced dacitic pyroclastic flows that reached the coast. Numerous satellitic cones and lava domes dot the flanks of the volcano down to the coast. Some of the post-caldera cones show evidence of wave-cut lake terraces; the more recent cones, some of which have been active historically, were formed after the caldera lake disappeared. Hot springs and fumaroles are found within the caldera and at Hot Springs Cone, 20 km to the SW. Historical eruptions have occurred since 1805 from cinder cones within the caldera. Source: Alaska Volcano Observatory (AVO) http://www.avo.alaska.edu/ SAKURA-JIMA Kyushu 31.585°N, 130.657°E; summit elev. 1117 m Based on information from JMA, the Tokyo VAAC reported explosions from Sakura-jima during 28 February-1 March. On 1 March, plumes rose to altitudes of 1.8-3 km (6,000-10,000 ft) a.s.l. and drifted S. JMA raised the Alert Level from 2 to 3 (on a scale of 1-5). During 1-2 March, three Vulcanian explosions occurred from Showa Crater, ejecting bombs that landed as far away as 1.3 km on 2 March. Deformation was also detected. The Tokyo VAAC reported that eruptions or explosions produced plumes that rose to altitudes of 2.7-3 km (9,000-10,000 ft) a.s.l. on 2 and 4 March, and an explosion occurred on 3 March. 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. Sources: Japan Meteorological Agency (JMA) http://www.jma.go.jp/jma/indexe.html, Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html Ongoing Activity COLIMA México 19.514°N, 103.62°W; summit elev. 3850 m During 25 February-3 March, white and gray plumes from Colima rose to altitudes of 3.9-4.5 km (12,800-14,800 ft) a.s.l. Geologic Summary. The Colima volcanic complex is the most prominent volcanic center of the western Mexican Volcanic Belt. It consists of two southward-younging volcanoes, Nevado de Colima (the 4,320 m high point of the complex) on the N and the historically active Volcán de Colima on the S. Volcán de Colima (also known as Volcán Fuego) is a youthful stratovolcano constructed within a 5-km-wide caldera, breached to the S, that has been the source of large debris avalanches. Major slope failures have occurred repeatedly from both the Nevado and Colima cones, and have produced a thick apron of debris-avalanche deposits on three sides of the complex. Frequent historical eruptions date back to the 16th century. Occasional major explosive eruptions (most recently in 1913) have destroyed the summit and left a deep, steep-sided crater that was slowly refilled and then overtopped by lava dome growth. Source: Gobierno del Estado de Colima http://www.colima-estado.gob.mx/2006/seguridad/indvolcan.php GALERAS Colombia 1.22°N, 77.37°W; summit elev. 4276 m INGEOMINAS reported that on several occasions during 25 February-2 March white gas plumes from Galeras with variable ash content rose to a peak altitude of 5.4 km (17,700 ft) a.s.l. and drifted NNW. On 3 March, the Alert Level was lowered from II (Orange; "probable eruption in term of days or weeks") to III (Yellow; "changes in the behavior of volcanic activity"). Geologic Summary. Galeras, a stratovolcano with a large breached caldera located immediately W of the city of Pasto, is one of Colombia's most frequently active volcanoes. The dominantly andesitic Galeras volcanic complex has been active for more than 1 million years, and two major caldera collapse eruptions took place during the late Pleistocene. Longterm extensive hydrothermal alteration has affected the volcano. This has contributed to large-scale edifice collapse that has occurred on at least three occasions, producing debris avalanches that swept to the W and left a large horseshoe-shaped caldera inside which the modern cone has been constructed. Major explosive eruptions since the mid Holocene have produced widespread tephra deposits and pyroclastic flows that swept all but the southern flanks. A central cone slightly lower than the caldera rim has been the site of numerous small-to-moderate historical eruptions since the time of the Spanish conquistadors. Source: Instituto Colombiano de Geología y Minería (INGEOMINAS) http://www.ingeominas.gov.co// KARYMSKY Eastern Kamchatka 54.05°N, 159.45°E; summit elev. 1536 m KVERT reported that seismic activity at Karymsky was at background levels during 21-28 February. Based on interpretations of seismic data, ash plumes likely rose to an altitude of 3.7 km (12,100 ft) a.s.l. On 24 February, pilots reported a dark plume near the volcano that rose to altitudes of 2.1 km (6,900 ft) a.s.l. Analysis of satellite imagery revealed a thermal anomaly on the lava dome during 21 and 24-25 February, and an ash plume that drifted 150 km NE on 21 February. The Level of Concern Color Code remained at Orange. Based on information from KEMSD and analysis of satellite imagery, the Tokyo VAAC reported that eruptions on 28 and 29 February produced plumes that rose to altitudes of 3-3.4 km (10,000-11,000 ft) a.s.l. and drifted W. On 3 March, an ash plume reported by the Yelizovo Airport (UHPP) rose to an altitude of 3.7 km (12,000 ft) a.s.l. and drifted E. 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. 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 KILAUEA Hawaii (USA) 19.421°N, 155.287°W; summit elev. 1222 m HVO reported that during 25 February-3 March lava flowed SE from underneath Kilauea's Thanksgiving Eve Breakout (TEB) and rootless shield complex through a lava tube system, reaching the Waikupanaha ocean entry and occasionally producing explosions. A sizable collapse of the Waikupanaha bench was seen by a visitor on 28 February. Thermal anomalies noted during most days on the coastal plain suggested surface flows. The vent in Halema'uma'u crater continued to produce a predominantly white plume that drifted mainly SW; incandescence was intermittently seen from the vent. Small amounts of ejected tephra, including Pele's hair, were routinely collected. On 26 February, geologists utilizing an infrared camera saw two spattering and episodically degassing vents about 100 m below the vent rim. The sulfur dioxide emission rate at the summit was 1,100 tonnes per day on 27 February and 1 March; the 2003-2007 average rate was 140 tonnes per day. 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/ REDOUBT Southwestern Alaska 60.485°N, 152.742°W; summit elev. 3108 m AVO reported that during February 25-March 3 seismic activity at Redoubt was variable. On 25 February, a small mud flow originating from a melt hole in the Drift Glacier traveled several hundred meters. Satellite images revealed that the next day another mudflow traveled several kilometers and covered a large portion of the Drift Glacier. Web camera views and satellite imagery showed no unusual activity; steam plumes within the summit crater were seen on the web camera on 26 and 1 March. Geologic Summary. Redoubt is a 3108-m-high glacier-covered stratovolcano with a breached summit crater in Lake Clark National Park about 170 km SW of Anchorage. Next to Mount Spurr, Redoubt has been the most active Holocene volcano in the upper Cook Inlet. Collapse of the summit of Redoubt 10,500-13,000 years ago produced a major debris avalanche that reached Cook Inlet. Holocene activity has included the emplacement of a large debris avalanche and clay-rich lahars that dammed Lake Crescent on the south side and reached Cook Inlet about 3500 years ago. Eruptions during the past few centuries have affected only the Drift River drainage on the north. Historical eruptions have originated from a vent at the north end of the 1.8-km-wide breached summit crater. The 1989-90 eruption of Redoubt had severe economic impact on the Cook Inlet region and affected air traffic far beyond the volcano. Source: Alaska Volcano Observatory (AVO) http://www.avo.alaska.edu/ SANTA MARIA Guatemala 14.756°N, 91.552°W; summit elev. 3772 m Based on analysis of satellite imagery, the Washington VAAC reported that on 26 February an eruption from Santa María's Santiaguito lava dome complex produced an ash plume that drifted SW. On 27 February and 2 March, INSIVUMEH reported that explosions produced ash plumes that rose to altitudes of 2.8-3.4 km (9,200-11,200 ft) a.s.l. and drifted SW. Ashfall was reported in nearby areas. Avalanches were seen SW of Caliente dome. Geologic Summary. Symmetrical, forest-covered Santa María volcano is one of a chain of large stratovolcanoes that rises dramatically above the Pacific coastal plain of Guatemala. The stratovolcano has a sharp-topped, conical profile that is cut on the SW flank by a large, 1-km-wide crater, which formed during a catastrophic eruption in 1902 and extends from just below the summit to the lower flank. The renowned Plinian eruption of 1902 followed a long repose period and devastated much of SW Guatemala. The large dacitic Santiaguito lava-dome complex has been growing at the base of the 1902 crater since 1922. Compound dome growth at Santiaguito has occurred episodically from four westward-younging vents, accompanied by almost continuous minor explosions and periodic lava extrusion, larger explosions, pyroclastic flows, and lahars. Sources: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH) http://www.insivumeh.gob.gt/, Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html SHIVELUCH Central Kamchatka (Russia) 56.653°N, 161.360°E; summit elev. 3283 m KVERT reported that seismic activity at Shiveluch was at background levels during 21-28 February. Based on interpretations of seismic data, ash plumes likely rose to an altitude of 5.5 km (18,000 ft) a.s.l. Lava flows continued to be active on the S and N flanks. Fumarolic activity was seen during 20-21 and 23-25 February. During 24-25 February, pilots reported dark plumes near the volcano that rose to altitudes of 5 km (16,400 ft) a.s.l. Analysis of satellite imagery revealed a daily thermal anomaly on the lava dome and an ash plume that drifted 40 km NNE on 25 February. The Level of Concern Color Code remained at Orange. Based on information from KEMSD and analysis of satellite imagery, the Tokyo VAAC reported that eruptions on 25 February and 4 March produced plumes that rose to altitudes of 4.9-5.8 km (16,000-19,000 ft) a.s.l. The plumes drifted W on 25 February. 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. During the 1990s, intermittent explosive eruptions took place 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 SOUFRIERE HILLS Montserrat 16.72°N, 62.18°W; summit elev. 915 m MVO reported that during 20-27 February activity from the Soufrière Hills lava dome was at a low level. On 24 February, a pyroclastic flow traveled E as far as the previous Tar River Valley coastline. The next day, a pyroclastic flow that traveled halfway down Tyre's Ghaut produced a small ash plume that drifted W. The Hazard Level remained at 3. Geologic Summary. The complex dominantly andesitic Soufrière Hills volcano occupies the southern half of the island of Montserrat. The summit area consists primarily of a series of lava domes emplaced along an ESE-trending zone. English's Crater, a 1-km-wide crater breached widely to the E, was formed during an eruption about 4,000 years ago in which the summit collapsed, producing a large submarine debris avalanche. Block-and-ash flow and surge deposits associated with dome growth predominate in flank deposits at Soufrière Hills. Non-eruptive seismic swarms occurred at 30-year intervals in the 20th century, but with the exception of a 17th-century eruption that produced the Castle Peak lava dome, no historical eruptions were recorded on Montserrat until 1995. Long-term small-to-moderate ash eruptions beginning in that year were later accompanied by lava-dome growth and pyroclastic flows that forced evacuation of the southern half of the island and ultimately destroyed the capital city of Plymouth, causing major social and economic disruption. Source: Montserrat Volcano Observatory (MVO) http://www.mvo.ms/ SUWANOSE-JIMA Ryukyu Islands (Japan) 29.635°N, 129.716°E; summit elev. 799 m Based on information from JMA, the Tokyo VAAC reported multiple explosions from Suwanose-jima during 26 February-1 March. On 1 March, resultant plumes rose to altitudes of 1.2-1.5 km (4,000-5,000 ft) a.s.l. and drifted E. On 2 March, an eruption produced a plume to an altitude of 1.5 km (5,000 ft) a.s.l. An explosion was reported on 3 March. 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 TUNGURAHUA Ecuador 1.467°S, 78.442°W; summit elev. 5023 m The IG reported that, although cloud cover occasionally prevented visual observation during 24 February-3 March, ash plumes from Tungurahua were seen and rose to altitudes of 5.5-10 km (18,000-32,800 ft) a.s.l. The plumes drifted in multiple directions. Ashfall was reported almost daily in areas to the SW, W, NW, N, and NE. Blocks were sometimes seen or heard rolling down the flanks, and roaring or explosion noises were noted. Strombolian activity at the summit was observed at night on 24 and 25 February. On 25 February, explosions caused the ground and large windows to vibrate. An explosion on 1 March was followed by an ash plume that rose to an altitude of 10 km (32,800 ft) a.s.l. and drifted NW. Incandescence at the crater was noted at night on 2 March. According to a news article from 3 March, ash covered at least 250 hectares of cropland, and additional land for cattle grazing. 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. Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG) http://www.igepn.edu.ec/, El Comercio http://www.elcomercio.com/noticiaEC.asp?id_noticia=260639&id_seccion=10 +++++++++++++++++++++++++++++++++++++ Sally Kuhn Sennert SI/USGS Weekly Volcanic Activity Report Editor Global Volcanism Program http://www.volcano.si.edu/reports/usgs/ Smithsonian Institution, National Museum of Natural History Department of Mineral Sciences, MRC-119 Washington, D.C., 20560 Phone: 202.633.1805 Fax: 202.357.2476 ============================================================== To unsubscribe from the volcano list, send the message: signoff volcano to: listserv@xxxxxxx, or write to: volcano-request@xxxxxxxx To contribute to the volcano list, send your message to: volcano@xxxxxxxx Please do not send attachments. ==============================================================
