********************************************************** SI/USGS Weekly Volcanic Activity Report 17-23 December 2008 ********************************************************** Sally Kuhn Sennert - Weekly Report Editor kuhns@xxxxxx URL: http://www.volcano.si.edu/reports/usgs/ New Activity/Unrest: | Kliuchevskoi, Central Kamchatka (Russia) | Llaima, Central Chile | Piton de la Fournaise, Reunion Island | Santa María, Guatemala | Soufrière Hills, Montserrat | Tungurahua, Ecuador Ongoing Activity: | Bagana, Bougainville | Chaitén, Southern Chile | Karymsky, Eastern Kamchatka | Kilauea, Hawaii (USA) | Machín, Colombia | Manam, Northeast of New Guinea (SW Pacific) | Masaya, Nicaragua | Rabaul, New Britain | Shiveluch, Central Kamchatka (Russia) | Suwanose-jima, Ryukyu Islands (Japan) This page is updated on Wednesdays, please see the GVP Home Page for news of the latest significant activity. 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 KLIUCHEVSKOI Central Kamchatka (Russia) 56.057°N, 160.638°E; summit elev. 4835 m KVERT reported that seismic activity at Kliuchevskoi was above background levels during 12-19 December. Strombolian activity was noted on 12, 13, 14, and 16 December, and lava effusion on the NW flank continued. Gas-and-steam plumes containing ash rose to an altitude of 8 km (26,200 ft) a.s.l. during 12-14 and 18 December. Analysis of satellite imagery revealed a large daily thermal anomaly in the crater. Ash plumes rose to altitudes of 4-8 km (13,100-26,200 ft) a.s.l. and drifted 500 km E, NE, and SE during 12-14 and 16-18 December. Based on analysis of satellite imagery, the Tokyo VAAC reported that on 21 December a possible eruption produced a plume to an altitude of 5.2 km (17,000 ft) a.s.l. The plumes drifted N. Ash emissions continued the next day. An eruption on 23 December produced an ash plume to an altitude of 5.2 km (17,000 ft) a.s.l. and drifted NE. 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. Sources: Kamchatkan Volcanic Eruption Response Team (KVERT), Tokyo Volcanic Ash Advisory Center (VAAC) LLAIMA Central Chile 38.692°S, 71.729°W; summit elev. 3125 m SERNAGEOMIN reported that 22 December an ash plume from Llaima rose to an altitude of 3.6 km (11,800 ft) a.s.l. A second smaller emission of ash was noted later that day. Geologic Summary. Llaima, one of Chile's largest and most active volcanoes, contains two main historically active craters, one at the summit and the other to the SE. The massive 3,125-m-high, glacier-covered stratovolcano has a volume of 400 cu km. A Holocene edifice built primarily of accumulated lava flows was constructed over an 8-km-wide caldera that formed about 13,200 years ago, following eruption of the 24 cu km Curacautín Ignimbrite. More than 40 scoria cones dot the volcano's flanks. Following the end of an explosive stage about 7,200 years ago, construction of the present edifice began, characterized by Strombolian, Hawaiian, and infrequent subplinian eruptions. Frequent moderate explosive eruptions with occasional lava flows have been recorded since the 17th century. Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN) PITON DE LA FOURNAISE Reunion Island 21.231°S, 55.713°E; summit elev. 2632 m OVPDLF reported that during 16-23 December lava from Piton de la Fournaise continued to issue from two fissures inside Dolomieu crater and pond at the bottom of the crater. Geologic Summary. Massive Piton de la Fournaise shield volcano on the island of Réunion is one of the world's most active volcanoes. Most historical eruptions have originated from the summit and flanks of a 400-m-high lava shield, Dolomieu, that has grown within the youngest of three large calderas. This depression is 8 km wide and is breached to below sea level on the eastern side. More than 150 eruptions, most of which have produced fluid basaltic lava flows within the caldera, have been documented since the 17th century. The volcano is monitored by the Piton de la Fournaise Volcano Observatory, one of several operated by the Institut de Physique du Globe de Paris. Source: Observatoire Volcanologique du Piton de la Fournaise (OVPDLF) SANTA MARIA Guatemala 14.756°N, 91.552°W; summit elev. 3772 m Based on analysis of satellite imagery, the Washington VAAC reported that during 17-20 and 22 December ash plumes from Caliente dome in Santa María's Santiaguito lava dome complex drifted SW, W, and NW. Plumes rose to an altitude of 5.8 km (19,000 ft) a.s.l. on 18 December. On 22 December, INSIVUMEH reported that white plumes drifted SW and avalanches occurred from the crater rim. Explosions the next day resulted in pyroclastic flows that descended the flanks and ash plumes to an altitude of 3.3 km (10,800 ft) a.s.l. that drifted S and SW. 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), Washington Volcanic Ash Advisory Center (VAAC) SOUFRIERE HILLS Montserrat 16.72°N, 62.18°W; summit elev. 915 m MVO reported that during 12-19 December activity from Soufrière Hills lava dome was characterized by increased lava extrusion, ash venting, rockfalls, and pyroclastic flows. Frequent pulses of ash rose from multiple places on the NW face of the lava dome and from a low on the dome behind Gages Mountain (as seen from Salem). On 13 December a pyroclastic flow traveled E down the Tar River Valley and reached the sea. Nighttime incandescence from the NW face was present during 16-19 December. Frequent rockfalls and several small pyroclastic flows descended Gages Valley. The largest pyroclastic flow, on 17 December, produced an ash cloud that rose to an altitude of 3 km (10,000 ft) a.s.l. On 18 December, observations of the lava dome confirmed significant growth on the SW flank. Photographs showed that most of the growth had taken place since 8 December; lava was filling in the area between the lava dome and Chance's Peak. Initial calculations suggested that the dome grew at a rate of 1 cubic meter per second during this time. Two small pyroclastic flows descended Galway's Valley on 19 December. Based on analysis of satellite imagery and information from MVO, the Washington VAAC reported that during 19-23 December ash plumes drifted W, WSW, SW, and S. Thermal anomalies were detected on satellite imagery on 19 and 21 December. A pilot observed an ash plume at an altitude of 4.3 km (14,000 ft) a.s.l. on 20 December. 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. Sources: Montserrat Volcano Observatory (MVO), Washington Volcanic Ash Advisory Center (VAAC) TUNGURAHUA Ecuador 1.467°S, 78.442°W; summit elev. 5023 m The IG reported that during 17-23 December steam-and-ash plumes from Tungurahua rose to altitudes of 6-11 km (19,700-36,100 ft) a.s.l. and drifted in multiple directions. Roaring noises were reported daily and ash fell in areas downwind (mostly to the SW) during 18-21 December. Nighttime incandescence was noted during 17 and 21-23 December. On 21 December, explosions vibrated the ground. The following day sounds resembling rolling blocks were reported, and incandescent blocks traveled 500 m down the flanks. On 23 December vibrations rattled windows in Guadalupe, about 11 km N. Geologic Summary. The steep-sided Tungurahua stratovolcano towers more than 3 km above its northern base. It sits ~140 km S of Quito, Ecuador's capital city, and is one of Ecuador's most active volcanoes. Historical eruptions have all originated from the summit crater. They have been accompanied by strong explosions and sometimes by pyroclastic flows and lava flows that reached populated areas at the volcano's base. The last major eruption took place from 1916 to 1918, although minor activity continued until 1925. The latest eruption began in October 1999 and prompted temporary evacuation of the town of Baños on the N side of the volcano. Source: Instituto Geofísico-Escuela Politécnica Nacional (IG) Ongoing Activity BAGANA Bougainville 6.140°S, 155.195°E; summit elev. 1750 m Based on analysis of satellite imagery, the Darwin VAAC reported that on 17 December an ash plume from Bagana rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted W. Geologic Summary. Bagana volcano, occupying a remote portion of central Bougainville Island, is one of Melanesia's youngest and most active volcanoes. Bagana is a massive symmetrical lava cone largely constructed by an accumulation of viscous andesitic lava flows. The entire lava cone could have been constructed in about 300 years at its present rate of lava production. Eruptive activity at Bagana is characterized by non-explosive effusion of viscous lava that maintains a small lava dome in the summit crater, although explosive activity occasionally producing pyroclastic flows also occurs. Lava flows form dramatic, freshly preserved tongue-shaped lobes up to 50-m-thick with prominent levees that descend the volcano's flanks on all sides. Source: Darwin Volcanic Ash Advisory Centre (VAAC) CHAITEN Southern Chile 42.833°S, 72.646°W; summit elev. 1122 m Based on analysis of satellite imagery, web camera views, and pilot observations, the Buenos Aires VAAC reported that during 18-19 and 23 December ash plumes from Chaitén continuously rose to altitudes 1.4-2.1 km (4,500-7,000 ft) a.s.l. and drifted ESE and SE. 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) KARYMSKY Eastern Kamchatka 54.05°N, 159.45°E; summit elev. 1536 m KVERT reported that during 12-19 December seismic activity at Karymsky was at background levels; possible explosions may have generated ash-and-gas plumes to an altitude of 2.5 km (8,200 ft) a.s.l. Analysis of satellite imagery revealed a thermal anomaly in the crater during 12-14 and 17 December and an ash plume that drifted 240 km SE on 16 December. The Level of Concern 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) KILAUEA Hawaii (USA) 19.421°N, 155.287°W; summit elev. 1222 m HVO reported that during 17-23 December lava flowed SE through a tube system from underneath Kilauea's Thanksgiving Eve Breakout (TEB) and rootless shield complex, reaching the Waikupanaha ocean entry. Thermal anomalies were detected on satellite imagery at the base of the pali and on the coastal plain. During 19-20 December geologists reported explosions at the ocean entry. Earthquakes were variously located beneath the caldera and along the S-flank fault. The vent in Halema'uma'u crater continued to produce a predominantly white plume that drifted mainly SW and deposited small amounts of tephra. 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) MACHIN Colombia 4.48°N, 75.392°W; summit elev. 2650+ m Observatory Vulcanológico and Sismológico de Manizales reported that a swarm of 98 earthquakes occurred at Machín on 17 December SE of the lava domes at depths of 2-6 km. The largest earthquake was M 2.6 at a depth of 3.8 km. Geologic Summary. The small Cerro Machín stratovolcano lies at the southern end of the Ruiz-Tolima massif about 20 km WNW of the city of Ibagué. A 3-km-wide caldera is breached to the S and contains three forested lava domes. Voluminous pyroclastic flows traveled up to 40 km from the volcano during eruptions in the mid-to-late Holocene perhaps associated with formation of the caldera. Late-Holocene eruptions produced block-and-ash flows that traveled through the breach in the caldera rim to the W and S. The latest known eruption of Volcán Cerro Machín took place about 800 years ago. Source: Instituto Colombiano de Geología y Minería (INGEOMINAS) MANAM Northeast of New Guinea (SW Pacific) 4.080°S, 145.037°E; summit elev. 1807 m Based on analysis of satellite imagery, the Darwin VAAC reported that on 19 December an ash plume from Manam rose to an altitude of 3 km (10,000 ft) a.s.l. Geologic Summary. The 10-km-wide island of Manam, lying 13 km off the northern coast of mainland Papua New Guinea, is one of the country's most active volcanoes. Four large radial valleys extend from the unvegetated summit of the conical 1807-m-high basaltic-andesitic stratovolcano to its lower flanks. These "avalanche valleys," regularly spaced 90 degrees apart, channel lava flows and pyroclastic avalanches that have sometimes reached the coast. Two summit craters are present; both are active, although most historical eruptions have originated from the southern crater, concentrating eruptive products during much of the past century into the SE avalanche valley. Frequent historical eruptions, typically of mild-to-moderate scale, have been recorded at Manam since 1616. Occasional larger eruptions have produced pyroclastic flows and lava flows that reached flat-lying coastal areas and entered the sea, sometimes impacting populated areas. Source: Darwin Volcanic Ash Advisory Centre (VAAC) MASAYA Nicaragua 11.984°N, 86.161°W; summit elev. 635 m Based on analysis of satellite imagery, the Washington VAAC reported that on 17 December a gas plume with possible ash rose to altitudes of 5.3-6.1 km (17,500-20,000 ft) a.s.l. Geologic Summary. Masaya is one of Nicaragua's most unusual and most active volcanoes. It is a broad, 6 x 11 km basaltic caldera with steep-sided walls up to 300 m high that is filled on its NW end by more than a dozen vents erupted along a circular, 4-km-wide fracture system. The twin volcanoes of Nindiri and Masaya, the source of historical eruptions, were constructed at the southern end of the fracture system and contain multiple summit craters. A major basaltic Plinian tephra was erupted from Masaya about 6,500 years ago. Historical lava flows cover much of the caldera floor and have confined a lake to the far eastern end of the caldera. A lava flow from the 1670 eruption overtopped the N caldera rim. Masaya has been frequently active since the time of the Spanish Conquistadors, when an active lava lake prompted several attempts to extract the volcano's molten "gold." Source: Washington Volcanic Ash Advisory Center (VAAC) RABAUL New Britain 4.271°S, 152.203°E; summit elev. 688 m RVO reported that during 13-19 December gray ash plumes from Rabaul caldera's Tavurvur cone rose to altitudes of 1.7-2.2 km (5,600-7,200 ft) a.s.l. and drifted in multiple directions. Ashfall was reported in areas downwind, including Rabaul town (3-5 km NW). Rumbling and roaring noises were reported on some days. Explosions or forceful emissions sometimes ejected incandescent lava fragments. Based on analysis of satellite imagery and information from RVO, the Darwin VAAC reported that on 22 and 23 December ash plumes rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted ENE. 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. Sources: Ima Itikarai, Rabaul Volcano Observatory (RVO), Darwin Volcanic Ash Advisory Centre (VAAC) 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 12-19 December. Based on interpretations of seismic data, ash plumes rose to an altitude of 4.5 km (14,800 ft) a.s.l. Visual observations of weak gas-and-steam emissions were noted during 12-14 and 18 December. Analysis of satellite imagery revealed a daily thermal anomaly on the lava dome. The Level of Concern Color Code remained at Orange. Based on information from KVERT and analysis of satellite imagery, the Tokyo VAAC reported that during 21-22 December eruptions produced plumes to altitudes of 5.8-8.5 km (19,000-28,000 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), Tokyo Volcanic Ash Advisory Center (VAAC) SUWANOSE-JIMA Ryukyu Islands (Japan) 29.635°N, 129.716°E; summit elev. 799 m Based on information from JMA, the Tokyo VAAC reported that during 17 and 19-20 December explosions or eruptions from Suwanose-jima produced plumes to an altitude of 1.5 km (5,000 ft) a.s.l. Plumes drifted E on 17 and 19 December. 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) +++++++++++++++++++++++++++++++++++++ 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. ==============================================================
