******************************************************* GVP/USGS Weekly Volcanic Activity Report 1-7 Feb. 2006 ******************************************************* From: Gari Mayberry <mayberry@xxxxxxxxxxxxxx> GVP/USGS Weekly Volcanic Activity Report 1-7 February 2006 http://www.volcano.si.edu/reports/usgs/ New Activity/Unrest: | Cleveland, USA Ongoing Activity: | Augustine, USA | Colima, México | Fuego, Guatemala | Galeras, Colombia | Karymsky, Russia | Kilauea, USA | Popocatépetl, México | Sakura-jima, Japan | Santa Ana, El Salvador | Santa María, Guatemala | Soufrière Hills, Montserrat | St. Helens, USA | Suwanose-jima, Japan | Tungurahua, Ecuador New Activity/Unrest CLEVELAND Aleutian Islands, USA 52.82°N, 169.95°W; summit elev. 1,730 m; All times are local (= UTC - 9 hours) An ash cloud emitted from Cleveland was detected on satellite imagery beginning at 0757 on 6 February, leading AVO to increase the Concern Color Code to Red from an unassigned code (Cleveland does not normally have a Concern Color Code because it is not seismically monitored, therefore no definitive information about background activity is available) <http://www.avo.alaska.edu/color_codes.php>. An image at 0900 on the same day showed a small ash cloud ~130 km ESE of the volcano. Initial data suggested that the cloud was at a height of ~6.7 km (22,000 ft) a.s.l. The ash cloud detached from the volcano and there was no indication of continuous ash emission. Ash had largely dissipated on satellite imagery by 1341. AVO received no information about additional ash emissions, so they decreased the Concern Color Code to Orange around 1655 on 6 February. Background. The symmetrical Mount Cleveland stratovolcano is situated at the western end of the uninhabited dumbbell-shaped Chuginadak Island in the east- central Aleutians. The 1,730-m-high stratovolcano is the highest of the Islands of Four Mountains group and is one of the most active in the Aleutians. Numerous large lava flows descend its flanks. It is possible that some 18th to 19th century eruptions attributed to Carlisle (a volcano located across the Carlisle Pass Strait to the NW) should be ascribed to Cleveland. In 1944 Cleveland produced the only known fatality from an Aleutian eruption. Recent eruptions from Mt. Cleveland have been characterized by short-lived explosive ash emissions, at times accompanied by lava fountaining and lava flows down the flanks. 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, Washington Volcanic Ash Advisory Center http://www.ssd.noaa.gov/VAAC/messages.html Cleveland Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1101-24- Ongoing Activity AUGUSTINE SW Alaska, USA 59.363°N, 153.43°W; summit elev. 1,252 m During 1-7 February, occasional pyroclastic flows continued to travel down Augustine's flanks and low-level ash plumes reached no higher than 4.6 km (15,000 ft) a.s.l. on satellite imagery. On 3 February, seismicity decreased significantly, but remained above background levels. Seismicity remained low throughout the remainder of the report period. Satellite imagery from the evening of 6 February showed a persistent thermal signal and occasional light ash emission. On 7 February, a steam plume was visible rising ~150 m (~500 ft) above the summit. AVO warned that further explosive activity producing ash clouds to heights over 7.6 km (25,000 ft) may still occur with little or no warning. Augustine remained at Concern Color Code Orange <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. 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 Augustine Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1103-01- COLIMA Western México 19.514°N, 103.62°W; summit elev. ~3,850 m During 4-7 February, small explosions occurred at Colima. The highest resultant ash plume reached ~8.5 km (28,000 ft) a.s.l. on 4 February. 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 1-3 February, weak-to-moderate explosions occurred at Fuego. Shock waves from the explosions were sometimes felt in villages near the volcano. Small avalanches of volcanic material traveled down Fuego's S and W flanks. 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. Sources: 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 30 January to 6 February, seismicity continued at Galeras, with an average of 200 small earthquakes occurring per day. In addition, slight deformation was recorded at the volcano. A flux of about 300 metric tons of sulfur dioxide was measured per day. Strong degassing occurred in several sectors of the active cone and around the lava dome. Steam rose to ~900 m above the volcano (or ~17,000 ft a.s.l.). 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= KARYMSKY Kamchatka Peninsula, Russia 54.05°N, 159.43°E; summit elev. 1,536 m According to reports from pilots of local airlines, ash emissions from Karymsky rose to 4-5 km (13,100-16,400 ft) a.s.l. during 30-31 January. The ash plumes extended 13-29 km from the volcano to the SW and SE, respectively. A thermal anomaly was visible at the lava dome during 27 January to 3 February, except when the volcano was obscured by clouds on the 28th. KVERT warned that activity from the volcano could affect nearby low-flying aircraft. Karymsky remained at Concern Color Code Orange <http://www.avo.alaska.edu/avo4/updates/color_code.html>. Background. 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 http://www.kcs.iks.ru/ivs/kvert/updates.shtml Karymsky Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1000-13= KILAUEA Hawaii, USA 19.43°N, 155.29°W; summit elev. 1,222 m During 2-7 February, lava from Kilauea continued to enter the sea at the East Lae`apuki area and surface lava flows were visible on the Pulama pali fault scarp. Background volcanic tremor was near normal levels at Kilauea's summit, with numerous shallow earthquakes continuing to occur at the summit and upper E rift zone. Volcanic tremor reached moderate levels at Pu`u `O`o. Small amounts of inflation and deflation occurred at the volcano during the report period. 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 During 1-7 February, several small-to-moderate emissions of steam, gas, and small amounts of ash occurred at Popocatépetl. On the 4th, an explosion produced a plume that rose to ~6.7 km (22,000 ft) a.s.l. 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= SAKURA-JIMA Kyushu, Japan 31.58°N, 130.67°E; summit elev. 1,117 m Based on information from JMA, the Tokyo VAAC reported that an explosion at Sakura-jima on 5 February produced a plume that reached a height of ~1.8 km (6,000 ft) a.s.l. and drifted N. Background. Sakura-jima, one of Japan's most active volcanoes, is a post- caldera cone of the Aira caldera at the northern half of Kagoshima Bay. Eruption of the voluminous Ito pyroclastic flow was associated with the formation of the 17 x 23-km-wide Aira caldera about 22,000 years ago. The construction of Sakura-jima began about 13,000 years ago and built an island that was finally joined to the Osumi Peninsula during the major explosive and effusive eruption of 1914. Activity at the Kita-dake summit cone ended about 4,850 years ago, after which eruptions took place at Minami-dake. Frequent historical eruptions, recorded since the 8th century, have deposited ash on Kagoshima, one of Kyushu's largest cities, located across Kagoshima Bay only 8 km from the summit. The largest historical eruption took place during 1471-76. Source: Tokyo Volcanic Ash Advisory Center http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html Sakura-jima Information from the Global Volcanism Program http://www.volcano.si.edu/gvp/world/volcano.cfm?vnum=0802-08= SANTA ANA El Salvador 13.853°N, 89.630°W; summit elev. 2,365 m During 27 January- 3 February, volcanic activity was at moderate levels at Santa Ana. On the 2nd, there was an increase in seismicity at the volcano, possibly related to an earthquake on the coast of Guatemala. There was also an increase in the sulfur-dioxide flux, with an average of 2,000 metric tons measured daily. Steam plumes rose to low levels above the volcano. The Alert Level at Santa Ana 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; All times are local (= UTC - 6 hours) During 1-3 February, weak-to-moderate explosions occurred at Santa María's Santiaguito lava-dome complex, producing plumes that rose to a maximum height of 1 km above the volcano (or 15,650 ft a.s.l.). On 1 February at 0657 and 0708, moderate explosions occurred that were accompanied by pyroclastic flows. Lava extrusion at Caliente Dome produced block-and-ash flows that descended the dome's S,E, and W sides. 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 Volcanic and seismic activity at Soufrière Hills were at elevated levels during 27 January to 3 February. Images taken by a remote camera at the beginning of the report period indicated that the lava dome continued to grow over a broad sector extending from the SW around to the NE. A pair of spines was observed on the SE side of the dome on 29 January, although both these and the fin-like structures (relatively thin, vertical planar spines) on the SE flank of the dome collapsed during the report period. Numerous small rockfalls were observed emanating from the S,E, and NE flanks of the lava dome, adding to the talus in the upper reaches of the Tar River Valley. Continued lava-dome growth was observed, particularly at the southern end, which was higher than the northern end of the dome. The sulfur-dioxide flux averaged 594 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= 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 1-7 February, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash. Occasional clear views of the volcano revealed incandescence on the currently growing lava lobe and a few incandescent rockfalls. 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 several explosions occurred at Suwanose-jima during 6-7 February. A resultant plume from an explosion on the 6th rose to 1.2 km (4,000 ft) a.s.l. and extended NW. 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; All times are local (= UTC - 5 hours) During 1-7 February, emissions of gas and ash occurred at Tungurahua. On 5 February at 0600, a moderate explosion occurred. A steam plume, with a small amount of ash, rose to ~1 km above the volcano (or 19,750 a.s.l.) and drifted SW. Light rainfall on the 7th generated a lahar in La Pampa area NW of the volcano. 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. ==============================================================
