************************************************************* GVP/USGS Weekly Volcanic Activity Report, 25-31 January 2006 ************************************************************* Reply-To: Gari Mayberry <mayberry@xxxxxxxxxxxxxx> GVP/USGS Weekly Volcanic Activity Report 25-31 January 2006 http://www.volcano.si.edu/reports/usgs/ New Activity/Unrest: | Augustine, USA Ongoing Activity: | Barren Island, Andaman Islands | Galeras, Colombia | Garbuna Group, Papua New Guinea | Kilauea, USA | Langila, Papua New Guinea | Lopevi, Vanuatu | Manam, Papua New Guinea | Planchón-Peteroa, Chile | Popocatépetl, México | Rabaul, Papua New Guinea | Soufrière Hills, Montserrat | St. Helens, USA | Tungurahua, Ecuador New Activity/Unrest AUGUSTINE SW Alaska, USA 59.363°N, 153.43°W; summit elev. 1,252 m; All times are local (= UTC - 9 hours) After several days with no ash emissions and relatively low seismicity, Augustine erupted again on 27 January around 2001, with the most vigorous activity beginning around 2024. The eruption lasted about 9 minutes. AVO raised the Concern Color Code from Orange to Red, the highest level. According to the National Weather Service (NWS), the ash plume produced from the eruption reached ~12.2 km (40,000 ft) a.s.l. and drifted SE. An ashfall advisory was issued by the NWS. That same day, an eruption at 2337 lasted 1 minute and produced an ash plume below 3 km (10,000 ft) a.s.l. On 28 January at 0204 a 2-minute-long eruption began that sent ash to a height of 7.9 km (26,000 ft) a.s.l. and drifted SE. Later that day a 3-minute-long eruption began at 0742 that sent a NE-drifting ash plume to a height of 7.6 km (25,000 ft) a.s.l. Augustine was in a state of continuous eruption from 1430 on 28 January through 31 January. The activity was characterized by steady ash emission and small pyroclastic flows. An observation flight on 29 January revealed diffuse drifting ash clouds at a height of ~7.6 km (25,000 ft) a.s.l. Also, ash-and- steam clouds rose from pyroclastic flows on the N flank of the volcano. Steam plumes rose from the NNE coastline, indicating that some of the pyroclastic flows had entered the sea. Satellite imagery on 31 January showed that plumes did not exceed 3.9 km (13,000 ft) a.s.l. and generally drifted N. According to a news article, Alaska Airlines cancelled flights to and from Anchorage on 30 and 31 January due to ash from Augustine in the airspace. Background. Augustine volcano, rising above Kamishak Bay in the southern Cook Inlet about 290 km SW of Anchorage, is the most active volcano of the eastern Aleutian arc. It consists of a complex of overlapping summit lava domes surrounded by an apron of volcaniclastic debris that descends to the sea on all sides. Few lava flows are exposed; the flanks consist mainly of debris- avalanche and pyroclastic-flow deposits formed by repeated collapse and regrowth of the volcano's summit. The latest episode of edifice collapse occurred during Augustine's largest historical eruption in 1883; subsequent dome growth has restored the volcano to a height comparable to that prior to 1883. The oldest dated volcanic rocks on Augustine are more than 40,000 years old. At least 11 large debris avalanches have reached the sea during the past 1800-2000 years, and five major pumiceous tephras have been erupted during this interval. Historical eruptions have typically consisted of explosive activity with emplacement of pumiceous pyroclastic-flow deposits followed by lava dome extrusion with associated block-and-ash flows. Sources: Alaska Volcano Observatory http://www.avo.alaska.edu/activity/avoreport.php?view=update, Anchorage Volcanic Ash Advisory Center http://www.ssd.noaa.gov/VAAC/OTH/AK/messages.html, Aero-News.net http://www.aero-news.net/index.cfm?contentBlockId=cc0af239-6345- 4561-9d80-4a9be7f5aaa1 Augustine Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1103-01- Ongoing Activity BARREN ISLAND Andaman Islands, Indian Ocean, India 12.29°N, 93.88°E; summit elev. 354 m During 12-13 January, a team from the Geological Survey of India visited Barren Island. They reported that dense clusters of incandescent tephra of various sizes were ejected from the crater. In addition to the eruption from the main crater, the scientists saw incandescence on the N flank of the volcanic cone and thin layers of incandescent material on the W slope. In comparison to activity during the early stages of the eruption in May-June 2005, activity had diminished considerably. The Darwin VAAC reported that ash plumes emitted from Barren Island during 26-27 January rose to ~3 km (10,000 ft) a.s.l. Background. 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 a 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 eruptions in the 19th century and more recently in 1991 and 1995. Sources: Geological Survey of India http://www.gsi.gov.in/barren.htm, Darwin Volcanic Ash Advisory Center http://www.bom.gov.au/info/vaac/advisories.shtml, Barren Island Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=0600-01= GALERAS Colombia 1.22°N, 77.37°W; summit elev. 4,276 m During 23-30 January, a lava dome continued to grow in the main crater of Galeras, and strong degassing occurred in several areas of the active cone and around the dome. Seismicity continued that was associated with the movement of fluid within the volcano, and slight deformation was recorded. Galeras remained at Alert Level 3 ("changes in the behavior of volcanic activity have been noted"). Background. 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. Long-term 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 http://www.ingeominas.gov.co/tmsingeominas/ModuloPublicacionPortal/PublicacionP ortal.asp Galeras Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1501-08= GARBUNA GROUP New Britain Island, Papua New Guinea 5.45°S, 150.03°E; summit elev. 564 m During 1-15 January, the two vents at the summit of Garbuna emitted small-to- moderate volumes of gas. There were no other unusual observations. Seismicity was low and dominated by occasional low-frequency earthquakes. Background. The basaltic-to-dacitic Garbuna volcano group consists of three volcanic peaks, Krummel, Garbuna, and Welcker. They are located along a 7-km N- S line above a shield-like foundation at the southern end of the Willaumez Peninsula. The central and lower peaks of the centrally located 654-m-high Garbuna volcano contain a large vegetation-free area that is probably the most extensive thermal field in Papua New Guinea. A prominent lava dome and blocky lava flow in the center of the thermal area have resisted destruction by thermal activity, and may be of Holocene age. Krummel volcano at the S end of the group contains a summit crater, breached to the NW. The highest peak of the Garbuna group is 1,005-m-high Welcker volcano, which has fed blocky lava flows that extend to the eastern coast of the peninsula. Source: Rabaul Volcano Observatory via the Darwin Volcanic Ash Advisory Center http://www.bom.gov.au/info/vaac/advisories.shtml Garbuna Group Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=0502-07= KILAUEA Hawaii, USA 19.43°N, 155.29°W; summit elev. 1,222 m During 30-31 January, lava from Kilauea continued to enter the sea at the East Lae`apuki area, building a new lava delta. Surface lava flows were visible on the Pulama pali fault scarp. On 31 January, the lava delta was 615 m long and 140 m wide. Background volcanic tremor was near normal levels at Kilauea's summit, with numerous shallow earthquakes occurring at the summit and upper E rift zone during several days. Volcanic tremor reached moderate levels at Pu`u `O`o. Background. 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 by lava flows less than about 1,100 years old; 70% of the volcano's surface is younger than 600 years. The latest Kilauea eruption began in January 1983 along the E rift zone. This long-term ongoing eruption from Pu`u `O`o-Kupaianaha has produced lava flows that have traveled 11-12 km from the vents to the sea, paving about 104 km2 of land on the S flank of Kilauea and building more than 200 hectares of new land. Source: US Geological Survey Hawaiian Volcano Observatory http://volcanoes.usgs.gov/update.html Kilauea information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1302-01- LANGILA New Britain Island, Papua New Guinea 5.53°S, 148.42°E; summit elev. 1,330 m A slight increase in vulcanian activity occurred at Langila's Crater 2 during 1-15 January. The increase was characterized by nearly continuous ash emissions that rose to 1-2 km above the summit (or 7,650-10,900 ft a.s.l.) and drifted WSW. Occasionally during the report period observers noted loud noises, incandescence, and weak emissions of glowing lava fragments. Background. Langila, one of the most active volcanoes of New Britain, consists of a group of four small overlapping composite cones on the lower eastern flank of the extinct Talawe volcano. Talawe is the highest volcano in the Cape Gloucester area of NW New Britain. A rectangular, 2.5-km-long crater is breached widely to the SE; Langila volcano was constructed NE of the breached crater of Talawe. An extensive lava field reaches the coast on the N and NE sides of Langila. Frequent mild-to-moderate explosive eruptions, sometimes accompanied by lava flows, have been recorded since the 19th century from three active craters at the summit of Langila. The youngest and smallest crater (no. 3 crater) was formed in 1960 and has a diameter of 150 m. Source: Rabaul Volcano Observatory via the Darwin Volcanic Ash Advisory Center http://www.bom.gov.au/info/vaac/advisories.shtml Langila Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=0502-01= LOPEVI Central Islands, Vanuatu 16.507°S, 168.346°E; summit elev. 1,413 m Following reports of plumes from Lopevi reaching heights of ~2.7 km (9,000 ft) a.s.l. on 24 and 25 January, the Wellington VAAC reported that plumes of "smoke" rose to ~2.1 km (7,000 ft) a.s.l. on 26 January and drifted S. They also reported that lava flowed down the S flank of the volcano on the 26th. Background. The small 7-km-wide conical island of Lopevi is one of Vanuatu's most active volcanoes. A small summit crater containing a cinder cone is breached to the NW and tops an older cone that is rimmed by the remnant of a larger crater. The basaltic-to-andesitic volcano has been active during historical time at both summit and flank vents, primarily on the NW and SE sides, producing moderate explosive eruptions and lava flows that reached the coast. Historical eruptions at the 1,413-m-high volcano date back to the mid- 19th century. The island was evacuated following eruptions in 1939 and 1960. The latter eruption, from a NW-flank fissure vent, produced a pyroclastic flow that swept to the sea and a lava flow that formed a new peninsula on the western coast. Source: Wellington VAAC http://www.ssd.noaa.gov/VAAC/OTH/NZ/messages.html Lopevi Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=0507-05= MANAM offshore New Guinea, Papua New Guinea 4.10°S, 145.06°E; summit elev. 1,807 m Mild eruptive activity occurred at Manam during 1-15 January, with occasional ash emissions during 1-4 January. Dull incandescence was visible on 1 and 2 January. Gas was emitted from Southern Crater during 1-7 January. Seismicity was at low levels during the report period. The Alert Level remained at 1, which reflected low activity. Background. The 10-km-wide island of Manam is one of Papua New Guinea's most active volcanoes. Four large radial valleys extend from the unvegetated summit of the conical 1,807-m-high 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. Five satellitic centers are located near the island's shoreline. Two summit craters are present; both are active, although most historical eruptions have originated from the southern crater, concentrating eruptive products during the past century into the SE avalanche valley. Frequent historical eruptions have been recorded since 1616. Source: Rabaul Volcano Observatory via the Darwin Volcanic Ash Advisory Center http://www.bom.gov.au/info/vaac/advisories.shtml Manam Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=0501-02= PLANCHÓN-PETEROA central Chile 35.240°S, 70.570°W; summit elev. 4,107 m The Buenos Aires VAAC reported that based on SIGMETs, increased fumarolic activity occurred at Planchón-Peteroa and Cerro Azul beginning on 26 January. Servicio Nacional de Geología y Minería clarified that intense fumarolic activity only occurred at Planchón-Petero around 25 January. Increased fumarolic activity is normal during the summer when snow melts in the crater and more steam is produced. Background. Planchón-Peteroa is an elongated complex volcano along the Chile- Argentina border with several overlapping calderas. Activity began in the Pleistocene with construction of the basaltic-andesite to dacitic Volcán Azufre, followed by formation of basaltic and basaltic-andesite Volcán Planchón, 6 km to the N. About 11,500 years ago, much of Azufre and part of Planchón collapsed, forming the massive Río Teno debris avalanche, which reached Chile's Central Valley. Subsequently, Volcán Planchón II was formed. The youngest volcano, andesitic and basaltic-andesite Volcán Peteroa, consists of scattered vents between Azufre and Planchón. Peteroa has been active into historical time and contains a small steaming crater lake. Historical eruptions from the Planchón-Peteroa complex have been dominantly explosive, although lava flows were erupted in 1837 and 1937. Sources: Servicio Nacional de Geología y Minería http://www.sernageomin.cl/servlet/page? _pageid=377&_dad=portal30&_schema=PORTAL30, Buenos Aires Volcanic Ash Advisory Center http://www.ssd.noaa.gov/VAAC/OTH/AG/messages.html Planchón-Peteroa Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1507-04= POPOCATÉPETL México 19.02°N, 98.62°W; summit elev. 5,426 m; All times are local (= UTC - 6 hours) During 24-30 January, several emissions of gas, steam, and small amounts of ash occurred at Popocatépetl. A moderate explosion on 26 December at 0957 produced an ash plume to ~3 km (9,850 ft) a.s.l. that drifted NE. Background. 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 http://www.cenapred.unam.mx/, Washington Volcanic Ash Advisory Center http://www.ssd.noaa.gov/VAAC/messages.html Popocatépetl Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1401-09= RABAUL New Britain Island, Papua New Guinea 4.271°S, 152.203°E; summit elev. 688 m Ash emissions from Rabaul caldera's active Tavurvur cone on 10,11,12, and 15 January rose over 1.5 km above the volcano's summit and drifted E. Seismicity was at low levels during 1-15 January. Background. 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: Rabaul Volcano Observatory via the Darwin Volcanic Ash Advisory Center http://www.bom.gov.au/info/vaac/advisories.shtml Rabaul Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=0502-14= SOUFRIÈRE HILLS Montserrat, West Indies 16.72°N, 62.18°W; summit elev. 1,052 m Activity at Soufrière Hills remained elevated during 20-27 January. Images taken by a remote camera showed that the lava dome continued to grow over a broad sector extending from the SW around to the NE. On 22 January, two new fin-like structures (relatively thin, vertical planar spines) were seen on the southeastern flank of the lava dome. Numerous small rockfalls were observed falling from the S, E, and NE flanks of the dome, adding to the talus in the upper reaches of the Tar River valley. Helicopter observations indicated continued dome growth, particularly in the SE. Background. 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 east, was formed during an eruption about 4000 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 http://www.mvo.ms/ Soufrière Hills Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1600-05= ST. HELENS Washington, USA 46.20°N, 122.18°W; summit elev. 2,549 m Growth of the new lava dome inside the crater of Mount St. Helens continued during 24-31 January, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash. On 24 January a shallow M 2.7 earthquake triggered a rockfall from the new lava dome, generating an ash plume that filled the crater before dissipating and drifting N over the pumice plain. Initial analysis of recent photographs from fixed cameras in the crater showed that the top of the currently active part of the new lava dome was at an elevation of ~2,240 m a.s.l., which is about 90 meters higher than it was in early November 2005. St Helens remained at Volcano Advisory (Alert Level 2); aviation color code Orange. Background. 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. Source: USGS Cascades Volcano Observatory http://vulcan.wr.usgs.gov/Volcanoes/MSH/CurrentActivity/framework.html St. Helens Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1201-05- TUNGURAHUA Ecuador 1.47°S, 78.44°W; summit elev. 5,023 m During 25-31 January, volcanic activity at Tungurahua remained at low levels with small emissions of steam and gas, with low ash content. On the 25th light rain caused lahars to flow in the NW sector of the volcano. The lahars descended a gorge from the village of Juive, causing the closure of the Banos- Penipe highway. Around the 28th, ash fell in the village of Puela. On the 31st, a steam-and-ash plume rose ~1 km above the volcano (or 19,750 ft a.s.l.) and drifted W. A small lahar traveled in the sector of Pampas, closing a road in the area for 2 hours. Background. 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 been restricted to 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 Geofisico-Escuela Poltecnica Nacional http://www.igepn.edu.ec/vulcanologia/tungurahua/actividad/informet.htm, Washington Volcanic Ash Advisory Center http://www.ssd.noaa.gov/VAAC/messages.html Tungurahua Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1502-08= ********************************************************* Gari Mayberry US Geological Survey/Global Volcanism Program Smithsonian Institution National Museum of Natural History MRC-119 Dept. of Mineral Sciences Washington, DC 20560-0119 Phone: 202.633.1805 Fax: 202.357.2476 mayberry@xxxxxxxxxxxxxx http://www.volcano.si.edu/reports/usgs/ ********************************************************** ============================================================== 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. ==============================================================
