********************************************* GVP/USGS Weekly Volcanic Activity Report 7-13 March 2007 http://www.volcano.si.edu/reports/usgs/ ********************************************* New Activity/Unrest: | Batu Tara, Indonesia | Chikurachki, Russia | Tungurahua, Ecuador Ongoing Activity: | Arenal, Costa Rica | Bagana, Papua New Guinea | Fuego, Guatemala | Kilauea, USA | Langila, Papua New Guinea | Lascar, Chile | Manam, Papua New Guinea | Pacaya, Guatemala | Rabaul, Papua New Guinea | Sangay, Ecuador | Soufrière Hills, Montserrat | St. Helens, USA | Ubinas, Perú New Activity/Unrest BATU TARA Lesser Sunda Islands, Indonesia 7.792°S, 123.579°E; summit elev. 748 m Based on satellite imagery, the Darwin VAAC reported that an ash cloud from Batu Tara reached an altitude of 4.3 km (14,000 ft) a.s.l. on 13 March and drifted N. The plume was identified on 14 March drifting NE. Geologic Summary. The small isolated island of Batu Tara in the Flores Sea about 50 km north of Lomblen Island contains a scarp on the eastern side similar to the Sciara del Fuoco of Italy's Stromboli volcano. Vegetation covers the flanks of Batu Tara to within 50 m of the 748-m-high summit. Batu Tara lies north of the main volcanic arc and is noted for its potassic leucite-bearing basanitic and tephritic rocks. The only known historical eruption from Batu Tara, during 1847-52, produced explosions and a lava flow. Source: Darwin Volcanic Ash Advisory Center http://www.bom.gov.au/info/vaac/advisories.shtml Batu Tara Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=0604-26= CHIKURACHKI Kuril Islands, Russia 50.325°N, 155.458°E; summit elev. 1,816 m During 11-12 March, a diffuse ash plume from Chikurachki was seen on satellite imagery drifting E. The plume rose to an estimated altitude of below 4.6 km (15,000 ft) a.s.l. Geologic Summary. Chikurachki, the highest volcano on Paramushir Island in the northern Kuriles, is actually a relatively small cone constructed on a high Pleistocene volcanic edifice. Oxidized scoria deposits covering the upper part of the young cone give it a distinctive red color. Lava flows from 1,816-m- high Chikurachki reached the sea and form capes on the NW coast; several young lava flows also emerge from beneath the scoria blanket on the eastern flank. The more erosionally modified Tatarinov group of six volcanic centers is located immediately to the S of Chikurachki. Tephrochronology gives evidence of only one eruption in historical time from Tatarinov, although its southern cone contains a sulfur-encrusted crater with fumaroles that were active along the margin of a crater lake until 1959. Source: Alaska Volcano Observatory http://www.avo.alaska.edu/ Chikurachki Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=0900-36= TUNGURAHUA Ecuador 1.47°S, 78.44°W; summit elev. 5,023 m IG reported that during 7-13 March, explosions from Tungurahua were accompanied by noises that resembled ?cannon shots.? Ash plumes rose to altitudes of 5.5-9 km (18,000-30,000 ft) a.s.l. and drifted NW and W. Ashfall was reported from areas downwind during 7-8 and 10-13 March. Incandescent material was ejected and rolled 300-500 m down the flanks during 7-10 and 12 March. 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 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. Source: Instituto Geofísico-Escuela Poltécnica Nacional http://www.igepn.edu.ec/ Tungurahua Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1502-08= Ongoing Activity ARENAL Costa Rica 10.46°N, 84.70°W; summit elev. 1,657 m In February, activity originating from Arenal's Crater C consisted of gas emissions, sporadic Strombolian eruptions, lava flows traveling N, and occasional avalanches from lava-flow fronts. Blocks from the lava-flow fronts traveled N, NE, and NW, periodically reaching vegetation where they started small fires. Volcanic activity was at relatively low levels, however, with few eruptions occurring and a small amount of pyroclastic material ejected. Eruptions produced ash plumes that rose about 2.2 km (7,100 ft) a.s.l. Ash and acid rain fell on the NE and SE flanks. Small avalanches of volcanic material traveled down several ravines. Crater D showed only fumarolic activity. Geologic Summary. Conical Volcán Arenal is the youngest stratovolcano in Costa Rica and one of its most active. The 1,657-m-high andesitic volcano towers above the eastern shores of Lake Arenal, which has been enlarged by a hydroelectric project. The earliest known eruptions of Arenal took place about 7,000 years ago. Growth of Arenal has been characterized by periodic major explosive eruptions at several-hundred-year intervals and periods of lava effusion that armor the cone. Arenal's most recent eruptive period began with a major explosive eruption in 1968. Continuous explosive activity accompanied by slow lava effusion and the occasional emission of pyroclastic flows has occurred since then from vents at the summit and on the upper western flank. Source: Observatorio Vulcanológico y Sismológico de Costa Rica-Universidad Nacional (OVSICORI-UNA) http://www.ovsicori.una.ac.cr/ Arenal Information from the Global Volcanism Program http://www.volcano.si.edu/gvp/world/volcano.cfm?vnum=1405-033 BAGANA Bougainville Island, Papua New Guinea 6.14°S, 155.19°E; summit elev. 1,750 m RVO reported that white vapor emissions from Bagana continued during 10 January- 9 March. Emissions were occasionally forceful, and on 3 March were accompanied by an ash cloud that drifted E. Summit incandescence was visible on 7 and 8 March. Based on satellite imagery, the Darwin VAAC reported that a diffuse plume rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted WSW on 10 March. 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. Sources: Herman Patia, Rabaul Volcano Observatory, Darwin Volcanic Ash Advisory Centre (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AU/messages.html Bagana Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=0505-02= FUEGO Guatemala 14.47°N, 90.88°W; summit elev. 3,763 m INSIVUMEH reported on 9 and 13 March that explosions from Fuego produced ash plumes that rose to altitudes of 4-4.2 km (13,000-13,800 ft) a.s.l. and drifted SE. Rumbling noises were heard from surrounding villages. Lava flows extended ~100-150 m W toward the Taniluyá River valley and avalanches occurred from the lava-flow fronts. On 12 March, incandescent material was ejected about 15-20 m above the central crater. Geologic Summary. 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, Meteorologia, e Hidrologia (INSIVUMEH) http://www.insivumeh.gob.gt/geofisica/boletin% 20formato.htm Fuego Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1402-09= KILAUEA Hawaii, USA 19.43°N, 155.29°W; summit elev. 1,222 m During 7-13 March, lava from Kilauea continued to flow across lava deltas into the ocean at the East Lae'apuki and Kamokuna entries. On 10 March, lava no longer entered the ocean at East Ka'ili'ili and likely branched off W towards the Royal Gardens subdivision. Steam plumes at East Ka'ili'ili possibly from water washing onto hot rocks, were visible on subsequent days. Incandescence was intermittently visible from several breakouts on the pali and from several vents in Pu'u 'O'o's crater. Tremor at Kilauea's summit continued at low levels. 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 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 broad areas on the S flank of Kilauea and adding new land beyond the former coastline. Source: US Geological Survey Hawaiian Volcano Observatory http://volcano.wr.usgs.gov/hvostatus.php 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 RVO reported that emission of ash clouds from Langila?s Crater 2 continued during 23 February-9 March. Incandescence was visible on 24 and 25 February and 6 and 8 March. Plumes rose to less that 2.3 km (7,500 ft) a.s.l. and drifted SE during 7-9 March. Geologic Summary. 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: Herman Patia, Rabaul Volcano Observatory Langila Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=0502-01= LASCAR northern Chile 23.37°S, 67.73°W; summit elev. 5,592 m The Buenos Aires VAAC reported that on 11 March an ash cloud from Lascar rose to 5.5-6.7 km (18,000-22,000 ft) a.s.l. and drifted E. Geologic Summary. Lascar is the most active volcano of the northern Chilean Andes. The andesitic-to-dacitic stratovolcano contains six overlapping summit craters and lies 5 km W of an older, higher stratovolcano, Volcán Aguas Calientes. Lascar consists of two major edifices; activity began at the eastern volcano and then shifted to the western cone. The largest eruption of Lascar took place about 26,500 years ago, and following the eruption of the Tumbres scoria flow about 9,000 years ago, activity shifted back to the eastern edifice, where three overlapping craters were formed. Frequent small-to- moderate explosive eruptions have been recorded from Lascar in historical time since the mid-19th century, along with periodic larger eruptions that produced ashfall hundreds of kilometers away from the volcano. The largest historical eruption of Lascar took place in 1993 and produced pyroclastic flows that extended up to 8.5 km NW of the summit. Source: Buenos Aires Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AG/messages.html Lascar Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1505-10= MANAM offshore New Guinea, Papua New Guinea 4.10°S, 145.06°E; summit elev. 1,807 m RVO reported that Manam's Main Crater emitted gray ash plumes on 22 February and during 3-11 March. The plumes rose to altitudes of 2.3-2.8 km (7,500-9,200 ft) a.s.l. and drifted SE. Incandescence was visible on 22 February and during 2-5 and 9-11 March. Vapor clouds and occasional diffuse ash clouds were emitted from South Crater during 3-11 March. Geologic Summary. 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: Herman Patia, Rabaul Volcano Observatory Manam Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=0501-02= PACAYA southern Guatemala 14.38°N, 90.60°W; summit elev. 2,552 m INSIVUMEH reported that on 9 and 12 March, fumurolic activity from Pacaya?s MacKenney Cone produced plumes that rose to 3 km (9,800 ft) a.s.l. and drifted S and SW. Incandescence was reflected in the plumes on 9 March. A lava flow from a crater on the NE flank was visible on 12 and 13 March to distances of 300 m. Geologic Summary. Eruptions from Pacaya, one of Guatemala's most active volcanoes, are frequently visible from Guatemala City, the nation's capital. Pacaya is a complex volcano constructed on the southern rim of the 14 x 16 km Pleistocene Amatitlán caldera. A cluster of dacitic lava domes occupies the caldera floor. The Pacaya massif includes the Cerro Grande lava dome and a younger volcano to the SW. Collapse of Pacaya volcano about 1,100 years ago produced a debris-avalanche deposit that extends 25 km onto the Pacific coastal plain and left an arcuate somma rim inside which the modern Pacaya volcano (MacKenney cone) grew. During the past several decades, activity at Pacaya has consisted of frequent Strombolian eruptions with intermittent lava flow extrusion on the flanks of MacKenney cone, punctuated by occasional larger explosive eruptions. Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH) http://www.insivumeh.gob.gt/geofisica/boletin%20formato.htm Pacaya Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1402-11= RABAUL New Britain Island, Papua New Guinea 4.271°S, 152.203°E; summit elev. 688 m RVO reported that during 6-13 March, Rabaul caldera's Tavurvur cone emitted ash plumes that rose to 0.9-2.7 km (3,000-8,900 ft) a.s.l. and drifted S, SE, W, and E. Loud roaring noises occasionally accompanied emissions and ashfall was reported from surrounding villages. Multiple explosions occurred. Large explosions produced shockwaves that rattled windows in Rabaul town and surrounding areas. The flanks were showered with incandescent lava fragments during 7-13 March. Geologic Summary. The low-lying Rabaul caldera on the tip of the Gazelle Peninsula at the NE end of New Britain forms a broad sheltered harbor. The outer flanks of the 688-m-high asymmetrical pyroclastic shield volcano are formed by thick pyroclastic-flow deposits. The 8 x 14 km caldera is widely breached on the E, where its floor is flooded by Blanche Bay. Two major Holocene caldera-forming eruptions at Rabaul took place as recently as 3,500 and 1,400 years ago. Three small stratovolcanoes lie outside the northern and NE caldera rims. Post-caldera eruptions built basaltic-to-dacitic pyroclastic cones on the caldera floor near the NE and western caldera walls. Several of these, including Vulcan cone, which was formed during a large eruption in 1878, have produced major explosive activity during historical time. A powerful explosive eruption in 1994 occurred simultaneously from Vulcan and Tavurvur volcanoes and forced the temporary abandonment of Rabaul city. Source: Herman Patia, Rabaul Volcano Observatory Rabaul Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=0502-14= SANGAY Ecuador 2.03°S, 78.34°W; summit elev. 5,188 m Based on information from IG, pilot reports, and satellite imagery, the Washington VAAC reported that eruptions from Sangay during 12-13 March produced ash plumes that rose to 7 km (23,000 ft) a.s.l. and drifted W. A hotspot was seen on satellite imagery. Geologic Summary. The isolated Sangay volcano, located E of the Andean crest, is the southernmost of Ecuador's volcanoes, and its most active. It has been in frequent eruption for the past several centuries. The steep-sided, 5,230-m-high glacier-covered volcano grew within horseshoe-shaped calderas of two previous edifices, which were destroyed by collapse to the E, producing large debris avalanches that reached the Amazonian lowlands. The modern edifice dates back to at least 14,000 years ago. Sangay towers above the tropical jungle on the E side; on the other sides flat plains of ash from the volcano have been sculpted by heavy rains into steep-walled canyons up to 600 m deep. The earliest report of an historical eruption was in 1628. More or less continuous eruptions were reported from 1728 until 1916, and again from 1934 to the present. The more or less constant eruptive activity has caused frequent changes to the morphology of the summit crater complex. Source: Washington Volcanic Ash Advisory Center http://www.ssd.noaa.gov/VAAC/messages.html Sangay Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1502-09= SOUFRIÈRE HILLS Montserrat, West Indies 16.72°N, 62.18°W; summit elev. 1,052 m During 2-9 March, lava-dome growth at Soufrière Hills continued and was concentrated on an E-facing lobe topped with blocky, spine-like protrusions. Rockfalls affected the E and NE flanks. Pyroclastic flows traveled 2 km and were confined E in the Tar River Valley. Heightened pyroclastic activity on 7 March resulted in an ash plume that rose to an estimated 2.4 km (8,000 ft) a.s.l. and drifted W. On 11 March, a pyroclastic flow traveled down the NE flank into White?s Ghaut. On 12 March, a large, blocky spine leaned steeply towards the NE. Based on satellite imagery, San Juan Weather Forecast Agency (WFO), and pilot reports, the Washington VAAC reported light ash and haze over several Caribbean islands during 7-10 March. Based on news articles, the presence of ash and dust from the Sahara Desert prompted some airlines in Puerto Rico to delay and cancel flights on 10 March. 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 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. Sources: Montserrat Volcano Observatory http://www.mvo.ms/, Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html, Associated Press http://www.iht.com/articles/ap/2007/03/10/news/CB-GEN-Puerto- Rico-Montserrat-Volcano.php 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 Data from deformation-monitoring instruments showed that during 7-13 March, the lava dome at Mount St. Helens continued to grow. Seismicity continued at low levels, punctuated by M 1.5-2.5 and occasionally larger earthquakes. Inclement weather occasionally inhibited visual observations. Geologic Summary. 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: US Geological Survey 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- UBINAS Perú 16.355°S, 70.903°W; summit elev. 5,672 m Based on pilot reports, the Buenos Aires VAAC reported continuous emissions from Ubinas on 11 March. Ash plumes rose to 5.5-6.1 km (18,000-20,000 ft) a.s.l. and drifted N. Geologic Summary. A small, 1.2-km-wide caldera that cuts the top of Ubinas, Peru's most active volcano, gives it a truncated appearance. Ubinas is the northernmost of three young volcanoes located along a regional structural lineament about 50 km behind the main volcanic front of Peru. The upper slopes of the stratovolcano, composed primarily of Pleistocene andesitic lava flows, steepen to nearly 45 degrees. The steep-walled, 150-m-deep summit caldera contains an ash cone with a 500-m-wide funnel-shaped vent that is 200 m deep. Debris-avalanche deposits from the collapse of the SE flank of Ubinas extend 10 km from the volcano. Widespread plinian pumice-fall deposits from Ubinas include some of Holocene age. Holocene lava flows are visible on the volcano's flanks, but historical activity, documented since the 16th century, has consisted of intermittent minor explosive eruptions. Source: Buenos Aires Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AG/messages.html Ubinas Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1504-02 +++++++++++++++++++++++++++++++++++++ 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. ==============================================================
