*********************************************************** SI/USGS Weekly Volcanic Activity Report 12-18 November 2008 *********************************************************** Sally Kuhn Sennert - Weekly Report Editor kuhns@xxxxxx URL: http://www.volcano.si.edu/reports/usgs/ New Activity/Unrest: | Akan, Hokkaido (Japan) | Barren Island, Andaman Islands (Indian Ocean) | Dalaffilla, Northeastern Africa | Nevado del Huila, Colombia | Reventador, Ecuador Ongoing Activity: | Chaitén, Southern Chile | Karymsky, Eastern Kamchatka | Kilauea, Hawaii (USA) | Kliuchevskoi, Central Kamchatka (Russia) | Popocatépetl, México | Rabaul, New Britain (SW Pacific) | Santa María, Guatemala | Shiveluch, Central Kamchatka (Russia) | Soufrière Hills, Montserrat | Suwanose-jima, Ryukyu Islands (Japan) The Weekly Volcanic Activity Report is a cooperative project between the Smithsonian's Global Volcanism Program and the US Geological Survey's Volcano Hazards Program. Updated by 2300 UTC every Wednesday, notices of volcanic activity posted on these pages are preliminary and subject to change as events are studied in more detail. This is not a comprehensive list of all of Earth's volcanoes erupting during the week, but rather a summary of activity at volcanoes that meet criteria discussed in detail in the "Criteria and Disclaimers" section. Carefully reviewed, detailed reports on various volcanoes are published monthly in the Bulletin of the Global Volcanism Network. Note: Many news agencies do not archive the articles they post on the Internet, and therefore the links to some sources may not be active. To obtain information about the cited articles that are no longer available on the Internet contact the source. New Activity/Unrest AKAN Hokkaido (Japan) 43.384°N, 144.013°E; summit elev. 1499 m On 17 November, JMA raised the Alert Level for Me-Akan (also known as Meakan-dake, which means Meakan Peak) of the Akan volcanic complex to "near-crater warning" (levels 2 and 3 on a 5-level scale) after the seismic network detected tremor that lasted 171 minutes. On 18 November, the summit was obscured by cloud cover but web camera views showed that the snow-covered S slopes had turned black. During an overflight later that day, JMA scientists noted that the ash covered an area up to 400 m away from Ponmachineshiri crater. Ballistic lithics several tens of centimeters in diameter were deposited around the crater. Geologic Summary. Akan is a 13 x 24 km, elongated caldera that formed more than 31,500 years ago immediately SW of Kutcharo caldera. Growth of four post-caldera stratovolcanoes, three at the SW end of the caldera and the other at the NE side, has restricted the size of the caldera lake. The 1-km-wide Nakamachineshiri crater was formed during a major pumice-and-scoria eruption about 13,500 years ago. Of the Holocene volcanoes of the Akan volcanic complex, only the Me-Akan group, E of Lake Akan, has been historically active, producing mild phreatic eruptions since the beginning of the 19th century. Me-Akan is composed of 9 overlapping cones. The main cone of Me-Akan proper has a triple crater at its summit. Historical eruptions at Me-Akan have consisted of minor phreatic explosions, but four major magmatic eruptions including pyroclastic flows have occurred during the Holocene. Source: Japan Meteorological Agency (JMA) http://www.jma.go.jp/jma/indexe.html BARREN ISLAND Andaman Islands (Indian Ocean) 12.278°N, 93.858°E; summit elev. 354 m Based on a pilot observation, the Darwin VAAC reported a lava flow from Barren Island on 17 November. A possible low-level ash plume was seen drifting W on satellite imagery. On 18 November, a pilot reported that an ash plume rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted WSW. Geologic Summary. Barren Island, a possession of India in the Andaman Sea about 135 km NE of Port Blair in the Andaman Islands, is the only historically active volcano along the N-S-trending volcanic arc extending between Sumatra and Burma (Myanmar). The 354-m-high island is the emergent summit of volcano that rises from a depth of about 2,250 m. The small, uninhabited 3-km-wide island contains a roughly 2-km-wide caldera with walls 250-350 m high. The caldera, which is open to the sea on the W, was created during a major explosive eruption in the late Pleistocene that produced pyroclastic-flow and -surge deposits. The morphology of a fresh pyroclastic cone that was constructed in the center of the caldera has varied during the course of historical eruptions. Lava flows fill much of the caldera floor and have reached the sea along the western coast during historical eruptions. Source: Darwin Volcanic Ash Advisory Centre (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AU/messages.html DALAFFILLA Northeastern Africa 13.792°N, 40.55°E; summit elev. 613 m Night-time satellite imagery from 8 November of the eruption that began on 3 November near Dalaffilla and Alu volcanoes revealed a multi-lobed lava-flow field with a primary channelized flow that traveled NE. The source appears to be a one or more NW-SE-trending eruptive fissures NW of Dalaffilla. The flow field on the 8 November image was an estimated 9.3 km long and 3 km wide, with an area of about 15 square kilometers. Thermal anomalies detected by satellites were present during 12-16 November. Geologic Summary. Dalaffilla, also referred to as Gabuli, is a small, but steep-sided conical stratovolcano that rises 300 m above surrounding lava fields SE of Alu volcano. This morphology, unusual for the Erta Ale Range volcanoes, results from the extrusion of viscous, silicic lava flows with primary slopes up to about 35 degrees. These silicic flows extend primarily to the east; on the west they are blocked by walls of a horst structure along the crest of the Erta Ale range. Other basaltic lava flows from regional fissures surround the 613-m-high volcano. Fumarolic activity occurs in the 100-m-wide summit crater and has weathered surrounding lava flows. Sources: Matthew Patrick, US Geological Survey Hawaiian Volcano Observatory (HVO) http://hvo.wr.usgs.gov/; Simon Carn, Michigan Technological University www.geo.mtu.edu; Hawai'i Institute of Geophysics and Planetology (HIGP) Thermal Alerts System http://hotspot.higp.hawaii.edu/ NEVADO DEL HUILA Colombia 2.93°N, 76.03°W; summit elev. 5365 m The Washington VAAC reported that on 11 November occasional emissions of gas and possible ash from Nevado del Huila were observed on satellite imagery. During 12-18 November, INGEOMINAS continued to receive reports of strong sulfur odors and ashfall in areas to the W and SW. They also noted that 14 instances of ash emissions were detected on satellite imagery during 13-14 November. Sulfur dioxide plumes were also detected on satellite imagery. According to the Washington VAAC, a pilot observed an ash plume on 14 November that rose to an altitude of 6.1 km (20,000 ft) a.s.l. and drifted SW. News articles stated that classes at educational institutions near the Páez and Símbola rivers were suspended while the Alert Level remained at Orange. Geologic Summary. Nevado del Huila, the highest active volcano in Colombia, is an elongated N-S-trending volcanic chain mantled by a glacier icecap. The andesitic-dacitic volcano was constructed within a 10-km-wide caldera. Volcanism at Nevado del Huila has produced six volcanic cones whose ages in general migrated from south to north. Two glacier-free lava domes lie at the southern end of the Huila volcanic complex. The first historical eruption from this little known volcano took place in the 16th century. Two persistent steam columns rise from the central peak, and hot springs are also present. Sources: Instituto Colombiano de Geología y Minería (INGEOMINAS) http://www.ingeominas.gov.co//, Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html, El Liberal http://www.elliberal.com.co/content/view/20076/77/ REVENTADOR Ecuador 0.077°S, 77.656°W; summit elev. 3562 m The IG reported that slight incandescence from Reventador's crater was seen at night during 11-12 November. Inclement weather prevented observations during 13-16 November. On 17 and 18 November, a seismic station situated on the NE flank of the central cone recorded a high number of rockfall signals that presumably originated from the active lava-flow fronts. Steam emissions rose from the crater. Geologic Summary. Reventador is the most frequently active of a chain of Ecuadorian volcanoes in the Cordillera Real, well E of the principal volcanic axis. It is a forested stratovolcano that rises above the remote jungles of the western Amazon basin. A 3-km-wide caldera breached to the E was formed by edifice collapse and is partially filled by a young, unvegetated stratovolcano that rises about 1,300 m above the caldera floor. Reventador has been the source of numerous lava flows as well as explosive eruptions that were visible from Quito in historical time. Frequent lahars in this region of heavy rainfall have constructed a debris plain on the eastern floor of the caldera. Source: Instituto Geofísico-Escuela Politécnica Nacional (IG) http://www.igepn.edu.ec/ Ongoing Activity CHAITEN Southern Chile 42.833°S, 72.646°W; summit elev. 1122 m Based on observations of satellite imagery, SIGMET notices, and web camera views, the Buenos Aires VAAC reported that during 12-17 November ash plumes from Chaitén continuously rose to altitudes 1.4-3.7 km (4,500-12,000 ft) a.s.l. and drifted NW, NNE, ENE, and E. A thermal anomaly was detected on satellite imagery on 12 November. 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. Source: Buenos Aires Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AG/messages.html KARYMSKY Eastern Kamchatka 54.05°N, 159.45°E; summit elev. 1536 m KVERT reported that seismic activity at Karymsky increased above background levels during 11-12 November. On 10 November, ash plumes were seen on satellite imagery drifting 38 km E and 28 km ENE. During 10-11 November, possible explosions may have generated ash plumes to an altitude of 3.8 km (12,500 ft) a.s.l. Also during 10-11 November, analysis of satellite imagery revealed a thermal anomaly in the crater; clouds prevented observations on the other days. The Level of Concern Color Code remained at Orange. Based on analysis of satellite imagery, information from the Yelizovo Airport (UHPP), and KEMSD notices, the Tokyo VAAC reported that an ash plume rose to an altitude of 2.7 km (9,000 ft) a.s.l. on 12 November. On 12 and 15 November, eruptions generated plumes that rose to an altitude of 3.4 km (11,000 ft) a.s.l. 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 12-18 November lava flowed SE through a tube system from underneath Kilauea's Thanksgiving Eve Breakout (TEB) and rootless shield complex, reaching the Waikupanaha ocean entry. Incandescence and active surface flows were seen on and at the base of the pali (fault scarp). Earthquakes were variously located beneath and to the S of the caldera, and along the S-flank fault. Beneath Halema'uma'u crater daily earthquakes ranged from 20 to 40 (background is about 40), but were too small to be located more precisely. The vent in Halema'uma'u crater continued to produce a predominantly white plume that drifted mainly SW and deposited small amounts of tephra. Night-time incandescence was seen at the base of the plume on the web camera for the first time in about a month, and sounds resembling distant surf and rockfalls were heard in the vicinity of the crater. The sulfur dioxide emission rate was 1,200 and 800 tonnes per day on 14 and 17 November, respectively; the 2003-2007 rate average 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/ KLIUCHEVSKOI Central Kamchatka (Russia) 56.057°N, 160.638°E; summit elev. 4835 m KVERT reported that seismic activity at Kliuchevskoi was above background levels during 7-13 November. Video and visual observations showed that during 8 and 10-12 November gas-and-steam plumes that contained a small amount of ash rose to an altitude of 5.1 km (16,700 ft) a.s.l. Analysis of satellite imagery revealed a daily thermal anomaly in the crater. The Level of Concern Color Code remained Orange. Geologic Summary. Kliuchevskoi is Kamchatka's highest and most active volcano. Since its origin about 7,000 years ago, the beautifully symmetrical, 4,835-m-high basaltic stratovolcano has produced frequent moderate-volume explosive and effusive eruptions without major periods of inactivity. More than 100 flank eruptions, mostly on the NE and SE flanks of the conical volcano between 500 m and 3,600 m elevation, have occurred during the past 3,000 years. The morphology of its 700-m-wide summit crater has been frequently modified by historical eruptions, which have been recorded since the late-17th century. Historical eruptions have originated primarily from the summit crater, but have also included major explosive and effusive events from flank craters. Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php POPOCATEPETL México 19.023°N, 98.622°W; summit elev. 5426 m CENAPRED reported that emissions of steam and gas from Popocatépetl were visible during 12-18 November. Based on analysis of satellite imagery and information from the Mexico City MWO, the Washington VAAC reported that on 17 November an ash plume rose to an altitude of 6.1 km (20,000 ft) a.s.l. and drifted NW and WSW. A thermal anomaly was also detected. According to CENAPRED, the emissions contained slight amounts of ash on 18 November. Geologic Summary. Popocatépetl, whose name is the Aztec word for smoking mountain, towers to 5,426 m 70 km SE of Mexico City and is North America's second-highest volcano. Frequent historical eruptions have been recorded since the beginning of the Spanish colonial era. A small eruption on 21 December 1994 ended five decades of quiescence. Since 1996 small lava domes have incrementally been constructed within the summit crater and destroyed by explosive eruptions. Intermittent small-to-moderate gas-and-ash eruptions have continued, occasionally producing ashfall in neighboring towns and villages. Sources: Centro Nacional de Prevencion de Desastres (CENAPRED) http://www.cenapred.unam.mx/es/, Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html RABAUL New Britain (SW Pacific) 4.271°S, 152.203°E; summit elev. 688 m Based on analysis of satellite imagery, the Darwin VAAC reported that during 12 and 16-18 November ash plumes from Rabaul caldera's Tavurvur cone rose to altitudes of 2.4-3 km (8,000-10,000 ft) a.s.l. and drifted NW and NNW. Geologic Summary. The low-lying Rabaul caldera on the tip of the Gazelle Peninsula at the NE end of New Britain forms a broad sheltered harbor. The outer flanks of the 688-m-high asymmetrical pyroclastic shield volcano are formed by thick pyroclastic-flow deposits. The 8 x 14 km caldera is widely breached on the E, where its floor is flooded by Blanche Bay.Two major Holocene caldera-forming eruptions at Rabaul took place as recently as 3,500 and 1,400 years ago. Three small stratovolcanoes lie outside the northern and NE caldera rims. Post-caldera eruptions built basaltic-to-dacitic pyroclastic cones on the caldera floor near the NE and western caldera walls. Several of these, including Vulcan cone, which was formed during a large eruption in 1878, have produced major explosive activity during historical time. A powerful explosive eruption in 1994 occurred simultaneously from Vulcan and Tavurvur volcanoes and forced the temporary abandonment of Rabaul city. Source: Darwin Volcanic Ash Advisory Centre (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AU/messages.html SANTA MARIA Guatemala 14.756°N, 91.552°W; summit elev. 3772 m Based on analysis of satellite imagery, the Washington VAAC reported that ash puffs from Santa María's Santiaguito lava dome complex drifted SW on 11 and 15 November. 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: 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 above background levels during 6-14 November. Based on interpretations of seismic data, ash plumes rose to an altitude of 6.8 km (22,300 ft) a.s.l. Hot avalanches descended the lava dome on 6 November and produced ash plumes that rose to an altitude of 4 km (13,100 ft) a.s.l. Analysis of satellite imagery revealed a daily thermal anomaly on the lava dome. On 10 November, an ash plume drifted 30 km E and gas-and-steam plumes drifted 50 km. The Level of Concern Color Code remained at Orange. Fumarolic activity was visible on the web camera on 8, 10, and 12 November. Based on information from KEMSD and analysis of satellite imagery, the Tokyo VAAC reported that on 13 and 16 November eruptions produced plumes to altitudes of 4.9-6.1 km (16,000-20,000 ft) a.s.l. 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 7-14 November the activity level at the Soufrière Hills lava dome increased slightly, but remained low, and there was no evidence of lava extrusion. Rockfalls were detected by the seismic network. Visual observations were hindered by clouds and vigorous steaming from the dome. Weak ash venting possibly occurred briefly on 13 November. 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 analysis of satellite imagery and information from JMA, the Tokyo VAAC reported multiple explosions or eruptions from Suwanose-jima during 12-16 November. Occasional plumes rose to altitudes of 1.5-2.1 km (5,000-7,000 ft) a.s.l. during 13-15 November. Geologic Summary. The 8-km-long, spindle-shaped island of Suwanose-jima in the northern Ryukyu Islands consists of an andesitic stratovolcano with two historically active summit craters. Only about 50 persons live on the sparsely populated island. The summit of the volcano is truncated by a large breached crater extending to the sea on the east flank that was formed by edifice collapse. Suwanose-jima, one of Japan's most frequently active volcanoes, was in a state of intermittent Strombolian activity from On-take, the NE summit crater, that began in 1949 and lasted nearly a half century. The largest historical eruption took place in 1813-14, when thick scoria deposits blanketed residential areas, after which the island was uninhabited for about 70 years. The SW crater produced lava flows that reached the western coast in 1813, and lava flows reached the eastern coast of the island in 1884. Source: Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html +++++++++++++++++++++++++++++++++++++ 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. ==============================================================
