******************************************************** GVP/USGS Weekly Volcanic Activity Report 4-10 Jan. 2006 ******************************************************** From: Gari Mayberry <mayberry@xxxxxxxxxxxxxx> GVP/USGS Weekly Volcanic Activity Report 4-10 January 2006 http://www.volcano.si.edu/reports/usgs/ Ongoing Activity: | Aoba, Vanuatu | Augustine, USA | Barren Island, Andaman Islands | Colima, México | Fuego, Guatemala | Kilauea, USA | Galeras, Colombia | Popocatépetl, México | Santa Ana, El Salvador | Santa María, Guatemala | Soufrière Hills, Montserrat | Spurr, USA | St. Helens, USA | Suwanose-jima, Japan | Tungurahua, Ecuador Ongoing Activity AOBA Vanuatu 15.40°S, 167.83°E; summit elev. 1,496 m According to a news report on 4 January, all of the 3,000 people displaced by the eruption of Aoba returned home. The eruption began on 27 November 2005. Background. Aoba is a massive 2,500 cu km basaltic shield volcano that is the most voluminous volcano of the New Hebrides archipelago. A pronounced NE-SW- trending rift zone dotted with scoria cones gives the 16 x 38 km island an elongated form. A broad pyroclastic cone containing three crater lakes is located at the summit of the Hawaiian-style shield volcano within the youngest of at least two nested calderas, the largest of which is 6 km in diameter. Post-caldera explosive eruptions formed the summit craters of Lake Voui (also spelled Vui) and Lake Manaro Ngoru about 360 years ago. A tuff cone was constructed within Lake Voui about 60 years later. The latest known flank eruption, about 300 years ago, destroyed the population of the Nduindui area near the western coast. Source: Radio New Zealand International News http://www.rnzi.com/pages/news.php?op=read&id=21418 Aoba Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=0507-03= AUGUSTINE SW Alaska, USA 59.363°N, 153.43°W; summit elev. 1,252 m During 30 December to 6 January, seismicity at Augustine increased slightly in comparison to the previous week. In addition, vigorous steaming was visible from several summit fumaroles during clear weather late in the week. Varied fumarole temperatures were recorded during a thermal survey on 4 January, but there was no significant change in the distribution of thermal features since 22 December. A significant increase in the sulfur-dioxide flux was measured on 4 January, in comparison to values on 20 December. Augustine remained at Concern Color Code Yellow <http://www.avo.alaska.edu/color_codes.php>. 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. Source: Alaska Volcano Observatory http://www.avo.alaska.edu/activity/avoreport.php?view=update Augustine Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1103-01- BARREN ISLAND Andaman Islands, Indian Ocean, India 12.29°N, 93.88°E; summit elev. 354 m Satellite imagery showed a thin ash plume emitted from Barren Island extending WNW during 5-7 January. 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. Source: 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= COLIMA Western México 19.514°N, 103.62°W; summit elev. ~3,850 m During 4-9 January, several small explosions at Colima produced ash plumes. The highest rising ash plume was produced by an explosion on 9 January and reached ~6.7 km (22,000 ft) a.s.l. The plume drifted NE and SW. Background. 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. Sources: Universidad de Colima http://www.ucol.mx/volcan/, Washington Volcanic Ash Advisory Center http://www.ssd.noaa.gov/VAAC/messages.html Colima Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1401-04= FUEGO Guatemala 14.47°N, 90.88°W; summit elev. 3,763 m During 4-9 January, moderate-to-strong explosions at Fuego produced ash plumes that rose to ~1 km above the volcano (or 15,600 ft a.s.l.). The explosions were accompanied by rumbling sounds and acoustic waves that shook windows and doors in villages near the volcano. Avalanches of volcanic material traveled down the volcano's SW flank. Background. Volcán Fuego, one of Central America's most active volcanoes, is one of three large stratovolcanoes overlooking Guatemala's former capital, Antigua. The scarp of an older edifice, Meseta, lies between 3,763-m-high Fuego and its twin volcano to the N, Acatenango. Construction of Meseta volcano continued until the late Pleistocene or early Holocene, after which growth of the modern Fuego volcano continued the southward migration of volcanism that began at Acatenango. Frequent vigorous historical eruptions have been recorded at Fuego since the onset of the Spanish era in 1524, and have produced major ashfalls, along with occasional pyroclastic flows and lava flows. The last major explosive eruption from Fuego took place in 1974, producing spectacular pyroclastic flows visible from Antigua. Source: Instituto Nacional de Sismologia, Vulcanologia, Meterologia, e Hidrologia http://www.insivumeh.gob.gt/principal/alertas.htm Fuego Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1402-09= GALERAS Colombia 1.22°N, 77.37°W; summit elev. 4,276 m During 2-9 January, Galeras emitted gas and small amounts of ash. In addition, heightened seismicity continued and small changes in deformation were measured. The sulfur-dioxide flux from the volcano varied between 490 and 1,500 metric tons per day. 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= KILAUEA Hawaii, USA 19.43°N, 155.29°W; summit elev. 1,222 m During 4-9 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. Background volcanic tremor was near normal levels at Kilauea's summit. Volcanic tremor reached moderate levels at Pu`u `O`o. Small amounts of deformation occurred at the volcano. 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- POPOCATÉPETL México 19.02°N, 98.62°W; summit elev. 5,426 m; All times are local (= UTC - 6 hours) A small explosion occurred at Popocatépetl on 6 January around 0042. According to the Washington VAAC, the resultant ash plume was visible on satellite imagery at a height of ~5.8 km (19,000 ft a.s.l.), extending NE. CENAPRED reported that after the explosion overall activity decreased to previous levels. 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= SANTA ANA El Salvador 13.853°N, 89.630°W; summit elev. 2,365 m During 30 December to 6 January, volcanic activity was moderate at Santa Ana. Seismicity was a bit over normal levels with small earthquakes occurring, which were interpreted as being associated with gas pulses. Continuous low- level emissions of steam and gas originated from the lagoon and from fumaroles within the crater. Gas rose 200-500 m above the crater (or 8,400-9,400 ft a.s.l.) and drifted SW. The sulfur-dioxide flux ranged between 180 and 1,476 metric tons per day. The Alert Level remained at Red, the highest level, within a 5-km radius around the volcano's summit crater. Background. Santa Ana, El Salvador's highest volcano, is a massive stratovolcano immediately W of Coatepeque caldera. Collapse of the volcano during the late Pleistocene or early Holocene produced a massive debris avalanche that swept into the Pacific, forming the Acajutla Peninsula. Reconstruction of the volcano rapidly filled the collapse scarp. The broad summit of the volcano is cut by several crescentic craters, and a series of parasitic vents and cones have formed along a 20-km-long fissure system that extends from near the town of Chalchuapa NNW of the volcano to the San Marcelino and Cerro Chino cinder cones on the SE flank. Historical activity, largely consisting of small-to-moderate explosive eruptions from both summit and flank vents, has been documented since the 16th century. The San Marcelino cinder cone on the SE flank produced a lava flow in 1722 that traveled 11 km to the E. Source: Servicio Nacional de Estudios Territoriales http://www.snet.gob.sv/ Santa Ana Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1403-02= SANTA MARÍA Guatemala 14.756°N, 91.552°W; summit elev. 3,772 m During 4-9 January, several explosions occurred at Santa María's Santiaguito lava-dome complex, producing ash plumes that rose to ~800 m above the volcano (or 15,000 ft a.s.l.) and drifted SW. Lava avalanches originated from the SW edge of the Caliente dome. Background. 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: Instituto Nacional de Sismologia, Vulcanologia, Meterologia, e Hidrologia http://www.insivumeh.gob.gt/geofisica/boletin%20formato.htm Santa María Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1402-03= SOUFRIÈRE HILLS Montserrat, West Indies 16.72°N, 62.18°W; summit elev. 1,052 m Activity at Soufrière Hills remained at elevated levels during 30 December to 6 January. Photographs revealed that the lava dome continued to grow throughout the report period over a broad sector extending from the SW around to the NE. Numerous small rockfalls continued from the S, E, and NE flanks of the lava dome, adding talus in the upper reaches of the Tar River valley to the NE. The sulfur-dioxide flux averaged 522 metric tons per day. 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= SPURR southwestern Alaska, USA 61.299°N, 152.251°W; summit elev. 3,374 m Seismicity remained above background levels at Spurr during 30 December to 6 January. Clear satellite and web camera views of the volcano showed no unusual activity. Spurr remained at Concern Color Code Yellow <http://www.avo.alaska.edu/color_codes.php>. Background. The 3,374-m-high summit of Mount Spurr, the highest volcano of the Aleutain arc, is a large lava dome constructed at the center of a roughly 5-km- wide horseshoe-shaped caldera that is open to the S. The volcano lies 130 km W of Anchorage, NE of Chakachamna Lake. The caldera was formed by a late- Pleistocene or early Holocene debris avalanche and associated pyroclastic flows that destroyed an ancestral Spurr volcano. The debris avalanche traveled more than 25 km to the SE, and the resulting deposit contains blocks as large as 100 m in diameter. Several ice-carved post-caldera cones or lava domes lie in the center of the caldera. The youngest vent, 2,309-m-high Crater Peak, formed at the southern breached end of the caldera and has been the source of about 40 identified Holocene tephra layers. Spurr's two historical eruptions, from Crater Peak in 1953 and 1992, deposited ash on the city of Anchorage. Source: Alaska Volcano Observatory http://www.avo.alaska.edu/avo4/updates/updates.htm Spurr Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1103-04- 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 4-9 January, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash. There were no significant changes in seismicity or deformation during the report period. Small earthquakes continued to be recorded every 2-3 minutes, with slightly larger events occurring intermittently. Two short lulls in the pattern of earthquake activity occurred after larger than normal earthquakes. 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- SUWANOSE-JIMA Ryukyu Islands, Japan 29.53°N, 129.72°E; summit elev. 799 m Based on information from JMA, the Tokyo VAAC reported that explosions occurred at Suwanose-jima on 1 and 10 January. An explosion on 10 January produced an ash plume to a height of ~1.8 km (6,000 ft) a.s.l. The heights of ash clouds from other explosions were not reported. Background. 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 E 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 around 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 http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html Suwanose-jima Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=0802-03= TUNGURAHUA Ecuador 1.47°S, 78.44°W; summit elev. 5,023 m IG reported that during 4-7 January, there was a slight change in the activity at Tungurahua in comparison to previous weeks, with more small-to-moderate explosions occurring. The explosions produced plumes of gas and small amounts of ash that rose to ~1 km above the volcano (or 19,750 ft a.s.l.). Seismicity remained at low levels. 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. ==============================================================
