******************************************************* SI/USGS Weekly Volcanic Activity Report 2-8 April 2008 ******************************************************** Sally Kuhn Sennert - Weekly Report Editor kuhns@xxxxxx URL: http://www.volcano.si.edu/reports/usgs/ New Activity/Unrest: | Kilauea, Hawaii (USA) | Manam, Northeast of New Guinea (SW Pacific) | Nevado del Huila, Colombia Ongoing Activity: | Colima, México | Karymsky, Eastern Kamchatka | Krakatau, Indonesia | Llaima, Central Chile | Rabaul, New Britain (SW Pacific) | Santa María, Guatemala | Shiveluch, Central Kamchatka (Russia) | Soufrière Hills, Montserrat | Tungurahua, Ecuador | Ubinas, Perú The Weekly Volcanic Activity Report is a cooperative project between the Smithsonian's Global Volcanism Program and the US Geological Survey's Volcano Hazards Program. Updated by 2300 UTC every Wednesday, notices of volcanic activity posted on these pages are preliminary and subject to change as events are studied in more detail. This is not a comprehensive list of all of Earth's volcanoes erupting during the week, but rather a summary of activity at volcanoes that meet criteria discussed in detail in the "Criteria and Disclaimers" section. Carefully reviewed, detailed reports on various volcanoes are published monthly in the Bulletin of the Global Volcanism Network. Note: Many news agencies do not archive the articles they post on the Internet, and therefore the links to some sources may not be active. To obtain information about the cited articles that are no longer available on the Internet contact the source. New Activity/Unrest KILAUEA Hawaii (USA) 19.421°N, 155.287°W; summit elev. 1222 m Based on observations during helicopter overflights, visual observations from HVO and National Park Service (NPS) crews, and web camera views, HVO reported that during 2-8 April lava flow activity from Kilauea's Thanksgiving Eve Breakout (TEB) shield was mostly concentrated at the E Waikupanaha, W Waikupanaha, and Ki ocean entries. Spattering and small steam explosions were intermittently reported. Occasionally, incandescence from a skylight adjacent to the TEB vents and from breakouts along the lava-tube system was noted. Diffuse incandescence was seen on the web camera at Pu'u 'O'o crater during 2-4 and 7-8 April. During the reporting period, Kilauea summit earthquakes were located beneath Halema`uma`u Crater, beneath the summit to the S and W, along the S-flank faults, and along the SW and E rift zones. The eruption from the vent in Halema'uma'u Crater continued to produce brown or white ash plumes that drifted mainly SW. During most nights incandescence was seen at the base of the plume and incandescent fragments were ejected from the vent. Based on pilot observations, the Washington VAAC reported that the plumes rose to altitudes of 3.4-3.8 km (11,200-12,500 ft) a.s.l. on 5 and 7 April. Seismic tremor was elevated. Sulfur dioxide emission rates from the summit area have been elevated at 2-4 times background values since early January. The emission rate fluctuated between 480-800 tonnes per day during 2-7 April, compared to a background rate of 150-200 tonnes per day. At Pu'u 'O'o crater the emission rate was 1,300 tonnes on 5 April. According to a news report, the Hawaii County Civil Defense issued a health advisory on 7 April for those living downwind of Halema'uma'u and Pu'u 'O'o craters. Residents of specified areas were then advised by the State Department of Health to evacuate because of projected dangerous level of sulfur dioxide. Residents of other areas were put on alert. Geologic Summary. Kilauea, one of five coalescing volcanoes that comprise the island of Hawaii, is one of the world's most active volcanoes. Eruptions at Kilauea originate primarily from the summit caldera or along one of the lengthy E and SW rift zones that extend from the caldera to the sea. About 90% of the surface of Kilauea is formed of lava flows less than about 1,100 years old; 70% of the volcano's surface is younger than 600 years. A long-term eruption from the East rift zone that began in 1983 has produced lava flows covering more than 100 sq km, destroying nearly 200 houses and adding new coastline to the island. Sources: US Geological Survey Hawaiian Volcano Observatory (HVO) http://hvo.wr.usgs.gov/, Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html, Honolulu Advertiser http://www.honoluluadvertiser.com/apps/pbcs.dll/article?AID=/20080408/BREAKING01/80408015/-1/LOCALNEWSFRONT MANAM Northeast of New Guinea (SW Pacific) 4.080°S, 145.037°E; summit elev. 1807 m Based on observations of satellite imagery and reports from RVO, the Darwin VAAC reported that a low-level plume from Manam drifted SW on 2 April. Geologic Summary. The 10-km-wide island of Manam, lying 13 km off the northern coast of mainland Papua New Guinea, is one of the country's most active volcanoes. Four large radial valleys extend from the unvegetated summit of the conical 1807-m-high basaltic-andesitic stratovolcano to its lower flanks. These "avalanche valleys," regularly spaced 90 degrees apart, channel lava flows and pyroclastic avalanches that have sometimes reached the coast. Two summit craters are present; both are active, although most historical eruptions have originated from the southern crater, concentrating eruptive products during much of the past century into the SE avalanche valley. Frequent historical eruptions, typically of mild-to-moderate scale, have been recorded at Manam since 1616. Occasional larger eruptions have produced pyroclastic flows and lava flows that reached flat-lying coastal areas and entered the sea, sometimes impacting populated areas. Source: Darwin Volcanic Ash Advisory Centre (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AU/messages.html NEVADO DEL HUILA Colombia 2.93°N, 76.03°W; summit elev. 5365 m According to news articles, communities surrounding Nevado del Huila responded to the raised Alert Level of Orange, established by INGEOMINAS on 29 March. The Local Committee of Disaster Prevention ordered the closing of a school with a student population of 1,100, declared the maximum alert for a local hospital, and facilitated meetings of multiple groups. Residents bought supplies and repaired roads that were key evacuation routes, and sirens were tested each day. Several populations in high-risk areas did not have systems of communication. On 7 April, residents in high-risk areas near the Páez river were evacuated to shelters as a precautionary measure. On 8 April, INGEOMINAS lowered the Alert Level to Yellow due to decreased seismicity during 2-8 April. In addition, no superficial changes associated with the recent activity were observed during an overflight on 5 April. Geologic Summary. Nevado del Huila, the highest active volcano in Colombia, is an elongated N-S-trending volcanic chain mantled by a glacier icecap. The andesitic-dacitic volcano was constructed within a 10-km-wide caldera. Volcanism at Nevado del Huila has produced six volcanic cones whose ages in general migrated from south to north. Two glacier-free lava domes lie at the southern end of the Huila volcanic complex. The first historical eruption from this little known volcano took place in the 16th century. Two persistent steam columns rise from the central peak, and hot springs are also present. Sources: Instituto Colombiano de Geología y Minería (INGEOMINAS) http://www.ingeominas.gov.co//, El Tiempo http://www.eltiempo.com/nacion/2008-04-05/ARTICULO-WEB-NOTA_INTERIOR-4075672.html, El Pais http://www.elpais.com.co/paisonline/notas/Abril042008/huilavolcanriesgo.html Ongoing Activity COLIMA México 19.514°N, 103.62°W; summit elev. 3850 m During 1-2 April, ash plumes from Colima rose to altitudes of 4.2-6.4 km (13,800-21,000 ft) a.s.l. and drifted NW, W, and SW. Incandescent avalanches descended the SW flank. On 4 April, incandescent material was propelled 150 m above the summit. An ash plume rose to an altitude of 4.5 km (14,800 ft) a.s.l. Based on observations of satellite imagery, the Washington VAAC reported that a brief puff of ash drifted SE on 7 April. Geologic Summary. 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: Gobierno del Estado de Colima http://www.colima-estado.gob.mx/2006/seguridad/indvolcan.php, Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html KARYMSKY Eastern Kamchatka 54.05°N, 159.45°E; summit elev. 1536 m KVERT reported that seismic activity at Karymsky was above background levels during 28-29 March and slightly above background levels during 30 March-4 April. Pilots observed ash plumes to altitudes of 5-7 km (16,400-23,000 ft) a.s.l. during 28-29 March. Based on seismic interpretation, ash plumes possibly rose to an altitude of 2.5 km (8,200 ft) a.s.l. on 2 April and weak ash explosions or avalanches may have occurred daily during the reporting period. Observations of satellite imagery revealed that a thermal anomaly was present in the crater on 28 March and 1, 2, and 3 April; an ash plume drifted S on 3 April. Ash deposits were noted in areas about 20 km E, 70 km SW, and 45-50 km S. The Level of Concern Color Code remained at Orange. Geologic Summary. Karymsky, the most active volcano of Kamchatka's eastern volcanic zone, is a symmetrical stratovolcano constructed within a 5-km-wide caldera that formed about 7,600-7,700 radiocarbon years ago. Construction of the Karymsky stratovolcano began about 2,000 years later. The latest eruptive period began about 500 years ago, following a 2,300-year quiescence. Much of the cone is mantled by lava flows less than 200 years old. Historical eruptions have been Vulcanian or Vulcanian-Strombolian with moderate explosive activity and occasional lava flows from the summit crater. Most seismicity preceding Karymsky eruptions has originated beneath Akademia Nauk caldera, which is located immediately S of Karymsky volcano and erupted simultaneously with Karymsky in 1996. Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php KRAKATAU Indonesia 6.102°S, 105.423°E; summit elev. 813 m CVGHM lowered the Alert Level for Anak Krakatau to 2 (on a scale of 1-4) on 1 April. Seismicity declined in early February, and eruption plumes and propelled incandescent material were not seen after 4 February. Visitors and residents were advised not to go within a 1.5-km radius of the summit. Geologic Summary. Renowned Krakatau volcano lies in the Sunda Strait between Java and Sumatra. Collapse of the ancestral Krakatau edifice, perhaps in 416 AD, resulted in a 7-km-wide caldera. Remnants of this volcano formed Verlaten and Lang Islands; subsequently Rakata, Danan and Perbuwatan volcanoes were formed, coalescing to create the pre-1883 Krakatau Island. Caldera collapse during the catastrophic 1883 eruption destroyed Danan and Perbuwatan volcanoes, and left only a remnant of Rakata volcano. The post-collapse cone of Anak Krakatau (Child of Krakatau), constructed within the 1883 caldera at a point between the former cones of Danan and Perbuwatan, has been the site of frequent eruptions since 1927. Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://portal.vsi.esdm.go.id/joomla/ LLAIMA Central Chile 38.692°S, 71.729°W; summit elev. 3125 m SERNAGEOMIN reported that during 28 March-4 April, fumarolic plumes from Llaima drifted several tens of kilometers mainly to the SE. Explosions produced ash and gas emissions. An overflight on 2 April of the main crater revealed that gas, pyroclastic material, and ash emissions, occasionally accompanied by small explosions, originated from three cones. On 4 April, several explosions were heard and incandescence was reflected in a gas-and-ash plume. Geologic Summary. Llaima, one of Chile's largest and most active volcanoes, contains two main historically active craters, one at the summit and the other to the SE. The massive 3,125-m-high, glacier-covered stratovolcano has a volume of 400 cu km. A Holocene edifice built primarily of accumulated lava flows was constructed over an 8-km-wide caldera that formed about 13,200 years ago, following eruption of the 24 cu km Curacautín Ignimbrite. More than 40 scoria cones dot the volcano's flanks. Following the end of an explosive stage about 7,200 years ago, construction of the present edifice began, characterized by Strombolian, hawaiian, and infrequent subplinian eruptions. Frequent moderate explosive eruptions with occasional lava flows have been recorded since the 17th century. Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN) http://www.sernageomin.cl/ RABAUL New Britain (SW Pacific) 4.271°S, 152.203°E; summit elev. 688 m RVO reported that during 1-9 April ash and steam-and-ash plumes rose to altitudes of 0.9-1.7 km (3,000-5,600 ft) a.s.l. and drifted E and SE. Ashfall was reported in Kokopo (about 20 km SE) on 2 April and in areas downwind during 4-7 April. Incandescence at night at the summit and occasional explosions were reported. Roaring noises were reported and sometimes rhythmic during 2-3 and 8-9 April. 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: Steve Saunders, Rabaul Volcano Observatory (RVO) SANTA MARIA Guatemala 14.756°N, 91.552°W; summit elev. 3772 m Based on observations of satellite imagery, the Washington VAAC reported that ash puffs from Santa María's Santiaguito lava dome complex drifted W on 2 April. During 3-7 April, INSIVUMEH reported that small explosions produced ash plumes; ashfall was reported in surrounding areas. Geologic Summary. Symmetrical, forest-covered Santa María volcano is one of a chain of large stratovolcanoes that rises dramatically above the Pacific coastal plain of Guatemala. The stratovolcano has a sharp-topped, conical profile that is cut on the SW flank by a large, 1-km-wide crater, which formed during a catastrophic eruption in 1902 and extends from just below the summit to the lower flank. The renowned Plinian eruption of 1902 followed a long repose period and devastated much of SW Guatemala. The large dacitic Santiaguito lava-dome complex has been growing at the base of the 1902 crater since 1922. Compound dome growth at Santiaguito has occurred episodically from four westward-younging vents, accompanied by almost continuous minor explosions and periodic lava extrusion, larger explosions, pyroclastic flows, and lahars. Sources: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH) http://www.insivumeh.gob.gt/, Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html SHIVELUCH Central Kamchatka (Russia) 56.653°N, 161.360°E; summit elev. 3283 m KVERT reported that seismic activity at Shiveluch was slightly above background levels during 28 March-4 April and hot avalanches possibly descended the growing lava dome daily. According to video footage and visual observations, fumarolic activity from the lava dome was observed during 28-29 March and 1-3 April. Observations of satellite imagery revealed that a thermal anomaly was present in the crater during the reporting period. The Level of Concern Color Code remained at Orange. Geologic Summary. The high, isolated massif of Shiveluch volcano (also spelled Sheveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group and forms one of Kamchatka's largest and most active volcanoes. The currently active Molodoy Shiveluch lava-dome complex was constructed during the Holocene within a large breached caldera formed by collapse of the massive late-Pleistocene Strary Shiveluch volcano. At least 60 large eruptions of Shiveluch have occurred during the Holocene, making it the most vigorous andesitic volcano of the Kuril-Kamchatka arc. Frequent collapses of lava-dome complexes, most recently in 1964, have produced large debris avalanches whose deposits cover much of the floor of the breached caldera. During the 1990s, intermittent explosive eruptions took place from a new lava dome that began growing in 1980. The largest historical eruptions from Shiveluch occurred in 1854 and 1964. Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php SOUFRIERE HILLS Montserrat 16.72°N, 62.18°W; summit elev. 915 m MVO reported that during 1-4 April the lava dome at Soufrière Hills changed very little, based on measurable parameters. Seismic activity was very low and one rockfall signal was recorded. The Alert Level remained elevated at 4 (on a scale of 0-5). Geologic Summary. The complex dominantly andesitic Soufrière Hills volcano occupies the southern half of the island of Montserrat. The summit area consists primarily of a series of lava domes emplaced along an ESE-trending zone. English's Crater, a 1-km-wide crater breached widely to the E, was formed during an eruption about 4,000 years ago in which the summit collapsed, producing a large submarine debris avalanche. Block-and-ash flow and surge deposits associated with dome growth predominate in flank deposits at Soufrière Hills. Non-eruptive seismic swarms occurred at 30-year intervals in the 20th century, but with the exception of a 17th-century eruption that produced the Castle Peak lava dome, no historical eruptions were recorded on Montserrat until 1995. Long-term small-to-moderate ash eruptions beginning in that year were later accompanied by lava-dome growth and pyroclastic flows that forced evacuation of the southern half of the island and ultimately destroyed the capital city of Plymouth, causing major social and economic disruption. Source: Montserrat Volcano Observatory (MVO) http://www.mvo.ms/ TUNGURAHUA Ecuador 1.467°S, 78.442°W; summit elev. 5023 m The IG reported that although visual observations were limited due to cloud cover, ash and ash-and-steam plumes from Tungurahua were spotted and rose to altitudes of 5.5-9 km (18,000-30,000 ft) a.s.l. during 2-8 April. Ash plumes drifted in almost all directions; ashfall was reported in areas downwind during 4-8 April. Explosions were occasionally registered by the seismic network and roaring and "cannon shot" noises were reported. Incandescent material rolled 0.5-1 km down the flanks during 2-4 and 6-7 April and Strombolian activity at the summit was noted during 3-4 April. Geologic Summary. The steep-sided Tungurahua stratovolcano towers more than 3 km above its northern base. It sits ~140 km S of Quito, Ecuador's capital city, and is one of Ecuador's most active volcanoes. Historical eruptions have all originated from the summit crater. They have been accompanied by strong explosions and sometimes by pyroclastic flows and lava flows that reached populated areas at the volcano's base. The last major eruption took place from 1916 to 1918, although minor activity continued until 1925. The latest eruption began in October 1999 and prompted temporary evacuation of the town of Baños on the N side of the volcano. Source: Instituto Geofísico-Escuela Politécnica Nacional (IG) http://www.igepn.edu.ec/ UBINAS Perú 16.355°S, 70.903°W; summit elev. 5672 m Based on pilot observations, the Buenos Aires VAAC reported that an ash plume from Ubinas rose to altitudes of 5.5-6.7 km (18,000-22,000 ft) a.s.l. and drifted E on 6 April. 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 +++++++++++++++++++++++++++++++++++++ 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. ==============================================================
