*********************************************************** SI/USGS Weekly Volcanic Activity Report 11-17 March 2009 *********************************************************** Sally Kuhn Sennert - Weekly Report Editor kuhns@xxxxxx URL: http://www.volcano.si.edu/reports/usgs/ New Activity/Unrest: | Ebeko, Paramushir Island | Galeras, Colombia | Hunga Tonga-Hunga Ha'apai, Tonga | Koryaksky, Eastern Kamchatka | Redoubt, Southwestern Alaska | Semeru, Eastern Java (Indonesia) Ongoing Activity: | Arenal, Costa Rica | Asama, Honshu | Batu Tara, Komba Island (Indonesia) | Chaitén, Southern Chile | Fuego, Guatemala | Karymsky, Eastern Kamchatka | Kilauea, Hawaii (USA) | Nevado del Huila, Colombia | Pacaya, Guatemala | Rabaul, New Britain | Sakura-jima, Kyushu | Santa María, Guatemala | Shiveluch, Central Kamchatka (Russia) | Suwanose-jima, Ryukyu Islands (Japan) | 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 EBEKO Paramushir Island 50.68°N, 156.02°E; summit elev. 1156 m Based on analysis of satellite imagery and information from Yelizovo Airport, the Tokyo VAAC reported that on 13 March an ash plume from Ebeko drifted E at an altitude of 0.6 km (2,000 ft) a.s.l. Geologic Summary. The flat-topped summit of the central cone of Ebeko volcano, one of the most active in the Kuril Islands, occupies the northern end of Paramushir Island. Three summit craters located along a SSW-NNE line form Ebeko volcano proper, at the northern end of a complex of five volcanic cones. The eastern part of the southern crater of Ebeko contains strong solfataras and a large boiling spring. The central crater of Ebeko is filled by a lake about 20 m deep whose shores are lined with steaming solfataras; the northern crater lies across a narrow, low barrier from the central crater and contains a small, cold crescentic lake. Historical activity, recorded since the late-18th century, has been restricted to small-to-moderate explosive eruptions from the summit craters. Intense fumarolic activity occurs in the summit craters of Ebeko, on the outer flanks of the cone, and in lateral explosion craters. Source: Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html GALERAS Colombia 1.22°N, 77.37°W; summit elev. 4276 m INGEOMINAS reported an explosive eruption from Galeras that began at 1555 on 13 March; the Alert Level was raised from II (Orange; "probable eruption in term of days or weeks") to I (Red; "imminent eruption or in progress"), on a scale of 4-1. Inclement weather prevented direct observations of the volcano. The Washington Volcanic Ash Advisory Center (VAAC) indicated that a plume rose to an altitude of 12.3 km (40,400 ft) a.s.l. and drifted NW. The eruption produced sounds heard in areas 10 km E and W. Ashfall was reported in multiple areas E and NW; a sulfur odor was also reported in some areas. On 14 March, gas plumes with some ash content rose to an altitude of 6.3 km (20,700 ft) a.s.l. The Alert Level was lowered to back to II. According to news articles, authorities ordered the evacuation of about 8,000 people living in high-risk areas, but few went to evacuation shelters. Geologic Summary. 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. Longterm 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. Sources: Instituto Colombiano de Geología y Minería (INGEOMINAS) http://www.ingeominas.gov.co//, El Tiempo http://www.eltiempo.com/colombia/occidente/de-alerta-roja-a-naranja-paso-el-volcan-galeras-en-la-noche-del-sabado_4874468-1 HUNGA TONGA-HUNGA HA'APAI Tonga 20.57°S, 175.38°W; summit elev. 149 m Observers flying near the area of Hunga Tonga-Hunga Ha'apai (about 62 km NNW of Nuku’alofa, the capital of Tonga) on 16 or 17 March reported seeing an eruption. Photos showed an eruption plume with a wide base that rose from the sea surface and mixed with meteorological clouds. Based on information from the Tonga airport and analysis of satellite imagery, the Wellington VAAC reported that on 18 March, a plume rose to altitudes of 4.6-7.6 km (15,000-25,000 ft) a.s.l. and drifted NE. Geologic Summary. The small islands of Hunga Tonga and Hunga Ha'apai cap a large seamount located about 30 km SSE of Falcon Island. The two linear andesitic islands are about 2 km long and represent the western and northern remnants of a the rim of a largely submarine caldera lying east and south of the islands. Hunga Tonga and Hunga Ha'apai reach an elevation of only 149 m and 128 m above sea level, respectively, and display inward-facing sea cliffs with lava and tephra layers dipping gently away from the submarine caldera. A rocky shoal 3.2 km SE of Hunga Ha'apai and 3 km south of Hunga Tonga marks the most prominent historically active vent. Several submarine eruptions have occurred at Hunga Tonga-Hunga Ha'apai since the first historical eruption in 1912. Sources: Steven Gates and Keizo Gates http://kzo.net/log/new-tonga-eruption, Wellington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/NZ/messages.html KORYAKSKY Eastern Kamchatka 53.320°N, 158.688°E; summit elev. 3456 m KVERT reported that seismic activity at Koryaksky was elevated on 6 and 8 March and at background levels on the other days during 7-13 March. Observers reported that gas plumes containing a small amount of ash rose to an altitude of 4 km (13,200 ft) a.s.l. and drifted in multiple directions during the reporting period. The plumes were also seen on satellite imagery. Ash deposits were seen near the volcano. The Level of Concern Color Code remained Orange. Based on information from the Yelizovo Airport and KVERT, the Tokyo VAAC reported that during 11-12 and 15 March ash plumes rose to altitudes of 3-5.2 km (10,000-17,000 ft) a.s.l. and drifted S, SE, E, and N. Geologic Summary. The large symmetrical Koryaksky stratovolcano is the most prominent landmark of the NW-trending Avachinskaya volcano group, which towers above Kamchatka's largest city, Petropavlovsk. Erosion has produced a ribbed surface on the eastern flanks of the 3456-m-high volcano; the youngest lava flows are found on the upper western flank and below SE-flank cinder cones. No strong explosive eruptions have been documented during the Holocene. Extensive Holocene lava fields on the western flank were primarily fed by summit vents; those on the SW flank originated from flank vents. Lahars associated with a period of lava effusion from south- and SW-flank fissure vents about 3900-3500 years ago reached Avacha Bay. Only a few moderate explosive eruptions have occurred during historical time. Koryaksky's first historical eruption, in 1895, also produced a lava flow. Sources: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php, Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html REDOUBT Southwestern Alaska 60.485°N, 152.742°W; summit elev. 3108 m AVO reported that during 11-15 March seismic activity at Redoubt was low but remained above background levels. On 12, 14, and 15 March clear web camera views showed steam plumes that rose just above the summit. At about 1305 on 15 March, seismic activity increased and about four hours of volcanic tremor ensued. AVO scientists aboard an overflight saw a steam-and-ash plume rise to an altitude of 4.6 km (15,000 ft) a.s.l. and produce minor ashfall on the summit crater floor and down the S flank. The emissions originated from a new vent, located just S of the 1990 lava dome and W of the prominent ice collapse feature near the N edge of the summit crater. About twenty minutes later, a sediment-laden flow occurred from a small area in the ice on the upper part of Drift glacier. Steam plumes were later noted. AVO raised the Aviation Color Code to Orange and the Alert Level to Watch. Clear web camera views on 17 March showed no unusual activity. Geologic Summary. Redoubt is a 3108-m-high glacier-covered stratovolcano with a breached summit crater in Lake Clark National Park about 170 km SW of Anchorage. Next to Mount Spurr, Redoubt has been the most active Holocene volcano in the upper Cook Inlet. Collapse of the summit of Redoubt 10,500-13,000 years ago produced a major debris avalanche that reached Cook Inlet. Holocene activity has included the emplacement of a large debris avalanche and clay-rich lahars that dammed Lake Crescent on the south side and reached Cook Inlet about 3500 years ago. Eruptions during the past few centuries have affected only the Drift River drainage on the north. Historical eruptions have originated from a vent at the north end of the 1.8-km-wide breached summit crater. The 1989-90 eruption of Redoubt had severe economic impact on the Cook Inlet region and affected air traffic far beyond the volcano. Source: Alaska Volcano Observatory (AVO) http://www.avo.alaska.edu/ SEMERU Eastern Java (Indonesia) 8.108°S, 112.92°E; summit elev. 3676 m Based on information from CVGHM, the Darwin VAAC reported that on 12 March an eruption from Semeru produced a plume to an altitude of 4.6 km (15,000 ft) a.s.l. Ash was not identified on satellite imagery. Geologic Summary. Semeru is the highest volcano on Java and one of its most active. The symmetrical stratovolcano rises abruptly to 3,676 m above coastal plains to the S and lies at the southern end of a volcanic massif extending N to the Tengger caldera. Semeru has been in almost continuous eruption since 1967. Frequent small-to-moderate Vulcanian eruptions have accompanied intermittent lava dome extrusion, and periodic pyroclastic flows and lahars have damaged villages below the volcano. A major secondary lahar on 14 May 1981 caused more than 250 deaths and damaged 16 villages. Source: Darwin Volcanic Ash Advisory Centre (VAAC) http://www.avo.alaska.edu/ Ongoing Activity ARENAL Costa Rica 10.463°N, 84.703°W; summit elev. 1670 m OVSICORI-UNA reported that during February, activity originating from Arenal's Crater C consisted of gas emissions, sporadic Strombolian eruptions, and occasional avalanches from lava-flow fronts that traveled down the SW flanks. Acid rain and small amounts of ejected pyroclastic material affected the NE and SE flanks. Small avalanches of volcanic material traveled down several ravines. Crater D showed only fumarolic activity. Geologic Summary. Conical Volcan 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 Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA) www.ovsicori.una.ac.cr ASAMA Honshu 36.403°N, 138.526°E; summit elev. 2568 m Based on information from JMA, the Tokyo VAAC reported that on 15 March an eruption from Asama produced a plume that rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted E. Geologic Summary. Asama, Honshu's most active volcano, is located at the junction of the Izu-Marianas and NE Japan arcs and has an historical record dating back at least to the 11th century. The modern cone of Maekake-yama is situated E of the horseshoe-shaped remnant of an older andesitic volcano, Kurofu-yama, which was destroyed by a late-Pleistocene landslide about 20,000 years before present (BP). Growth of a dacitic and rhyolitic lava cone was accompanied by pumiceous pyroclastic flows, the largest of which occurred about 14,000-11,000 years BP, and by growth of the Ko-Asama-yama lava dome on the E flank. Maekake-yama is probably only a few thousand years old, but has had several major Plinian eruptions, the last two of which occurred in 1108 and 1783 AD. Source: Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html BATU TARA Komba Island (Indonesia) 7.792°S, 123.579°E; summit elev. 748 m Based on analysis of satellite imagery, the Darwin VAAC reported that on 11 March ash plumes from Batu Tara rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted N and NW. Geologic Summary. The small isolated island of Batu Tara in the Flores Sea about 50 km north of Lembata (formerly 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 first historical eruption from Batu Tara, during 1847-52, produced explosions and a lava flow. Source: Darwin Volcanic Ash Advisory Centre (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AU/messages.html CHAITEN Southern Chile 42.833°S, 72.646°W; summit elev. 1122 m Based on web camera views, analysis of satellite imagery, and SIGMET notices, the Buenos Aires VAAC reported that during 11-15 March ash plumes from Chaitén rose to altitudes of 2.1-3.7 km (7,000-12,000 ft) a.s.l. and drifted NNE, NE, E, and SE. A thermal anomaly was detected in satellite imagery on 15 March. Geologic Summary. Chaitén is a small, glacier-free caldera with a Holocene lava dome located 10 km NE of the town of Chaitén on the Gulf of Corcovado. A pyroclastic-surge and pumice deposit considered to originate from the eruption that formed the elliptical 2.5 x 4 km wide summit caldera was dated at about 9400 years ago. A rhyolitic, 962-m-high obsidian lava dome occupies much of the caldera floor. Obsidian cobbles from this dome found in the Blanco River are the source of prehistorical artifacts from archaeological sites along the Pacific coast as far as 400 km away from the volcano to the north and south. The caldera is breached on the SW side by a river that drains to the bay of Chaitén, and the high point on its southern rim reaches 1122 m. Source: Buenos Aires Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AG/messages.html FUEGO Guatemala 14.473°N, 90.880°W; summit elev. 3763 m On 12, 16, and 17 March, INSIVUMEH reported that explosions from Fuego produced ash plumes that rose to altitudes of 4.2-4.8 km (13,800-15,700 ft) a.s.l. and drifted S and SW. Incandescent material was ejected 75 m into the air. Some explosions produced rumbling sounds heard in nearby towns. White plumes rose 150-200 m above the summit. During 16-17 March, fine ashfall was reported in areas downwind. Based on analysis of satellite imagery and SIGMET notices, the Washington VAAC reported that during 12-13 March ash plumes drifted S and SW. On 13 March, the ash plume rose to an altitude of 5 km (16,500 ft) a.s.l. 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. 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 KARYMSKY Eastern Kamchatka 54.05°N, 159.45°E; summit elev. 1536 m KVERT reported that seismic activity at Karymsky was at background levels during 6-13 March. Based on interpretations of seismic data, ash plumes likely rose to an altitude of 3 km (10,000 ft) a.s.l. Analysis of satellite imagery revealed a thermal anomaly on the lava dome during 6-12 March, and ash plumes that drifted in multiple directions during the reporting period. The Level of Concern Color Code remained at Orange. Based on information from KVERT and pilot observations, the Tokyo VAAC reported that on 13 March an ash plume rose to an altitude of 4 km (13,000 ft) a.s.l. and drifted E. 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. Sources: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php, Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html KILAUEA Hawaii (USA) 19.421°N, 155.287°W; summit elev. 1222 m During 11-17 March, HVO reported that lava flowed SE from underneath Kilauea's Thanksgiving Eve Breakout (TEB) and rootless shield complex through a lava tube system, reaching the Waikupanaha ocean entry and occasionally producing explosions. Thermal anomalies noted during most days on the coastal plain suggested surface flows. During 11-13 March, scattered surface flows near the Prince lobe were noted. On 13 March, a 30-m-wide lava flow entered the ocean at Kupapa'u, a second ocean entry location to the W of Waikupanaha. Kupapa'u was active during 14-17 March. The vent in Halema'uma'u crater continued to produce a predominantly white plume; southwesterly winds often caused poor air quality in communities to the N. Incandescence from the vent was seldom seen. On 12 March, seemingly fresh spatter was collected from bins placed near the plume; minimal amounts of ash were collected the next day. The sulfur dioxide emission rate at the summit was 1,000 tonnes per day on 13 March; the 2003-2007 average rate was 140 tonnes per day. Field visits to the caldera floor indicated that there was an ash emission event sometime before dawn on 15 March, possibly following a wall collapse within the Halema'uma'u vent. Ash coated several monitoring instruments and was detected in Volcano, about 6 km NE. On 16 March, the plume drifted N and dusted HVO with ash. 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. Source: US Geological Survey Hawaiian Volcano Observatory (HVO) http://hvo.wr.usgs.gov/ NEVADO DEL HUILA Colombia 2.93°N, 76.03°W; summit elev. 5364 m INGEOMINAS reported that during 11-17 March whitish colored gas plumes from Nevado del Huila viewed through the web camera rose to a maximum altitude of 6.4 km (21,000 ft) a.s.l. and drifted E and NW. The Alert Level remained at Orange. 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. Source: Instituto Colombiano de Geología y Minería (INGEOMINAS) http://www.ingeominas.gov.co// PACAYA Guatemala 14.381°N, 90.601°W; summit elev. 2552 m On 12, 16, and 17 March, INSIVUMEH reported that fumarolic plumes from Pacaya's MacKenney cone drifted S at a low altitude. Lava flows, 25-200 m long, traveled S, SW, and W. 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 Amatitlan 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/ RABAUL New Britain 4.271°S, 152.203°E; summit elev. 688 m RVO reported that during 9-15 March gray ash plumes from Rabaul caldera's Tavurvur cone rose to a maximum altitude of 2.7 km (8,900 ft) a.s.l. Incandescence was seen at night and incandescent tephra was occasionally ejected from the crater during periods of heightened activity. Light ashfall was reported in areas to the NW and SE. 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: Ima Itikarai, Rabaul Volcano Observatory (RVO) SAKURA-JIMA Kyushu 31.585°N, 130.657°E; summit elev. 1117 m On 14 March, JMA reported two Vulcanian explosions from Sakura-jima to heights of 400-500 m above an unspecified crater; ejected bombs landed as far away as 800 m. Both the summit crater and Showa crater on the E flank had recently been active. Based on information from JMA, the Tokyo VAAC reported that an eruption on 17 March produced a plume that rose to an altitude of 2.1 km (6,000 ft) a.s.l. and drifted E. Geologic Summary. 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. Sources: Japan Meteorological Agency (JMA) http://www.jma.go.jp/jma/indexe.html, Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html SANTA MARIA Guatemala 14.756°N, 91.552°W; summit elev. 3772 m On 12, 16, and 17 March, INSIVUMEH reported that explosions from Santa María's Santiaguito lava dome complex produced ash plumes that rose to altitudes of 2.7-3.5 km (8,900-11,500 ft) a.s.l. and drifted E and SW. A few avalanches originated from an active lava flow and traveled down the SW flank. White plumes rose 100 m and drifted W. Based on analysis of satellite imagery, the Washington VAAC reported that on 12 March an ash plume drifted S. On 15 March, an ash plume rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted SW and WSW. 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 during 6-13 March seismic activity at Shiveluch was above background levels and strong fumarolic activity was seen. Based on interpretations of seismic data, ash plumes likely rose to an altitude of 6.2 km (20,300 ft) a.s.l. Incandescence from the lava dome was seen at night. According to observers, ash plumes from hot avalanches rose to an altitude of 6 km (19,700 ft) a.s.l. and drifted SE during 9-10 March. Analysis of satellite imagery revealed a daily thermal anomaly on the lava dome and ash plumes that drifted about 175 km SE during 7 and 10-11 March. 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 SUWANOSE-JIMA Ryukyu Islands (Japan) 29.635°N, 129.716°E; summit elev. 799 m Based on information from JMA, the Tokyo VAAC reported that on 15 and 16 March eruptions from Suwanose-jima produced plumes that rose to an altitude of 1.5 km (5,000 ft) a.s.l. Plumes drifted E on 15 March. Geologic Summary. 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 east 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 about 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 (VAAC) http://www.kscnet.ru/ivs/kvert/index_eng.php TUNGURAHUA Ecuador 1.467°S, 78.442°W; summit elev. 5023 m On 11 March, IG reported that a steam-and-ash plume from Tungurahua rose 600 m above the summit and drifted E and NE. Fumaroles on the NE flank were active. On 12 and 16 March, plumes with low ash content rose to altitudes of 6-7 km (19,700-23,000 ft) a.s.l. and drifted NE. Steam plumes were occasionally seen during 13-14 and 17 March, and a plume rose 300-500 m above the summit and drifted E and W on 15 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 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 a SIGMET notice and analysis of satellite imagery, the Buenos Aires VAAC reported that during 11-12 March ash plumes from Ubinas rose to altitudes of 5.5-7.3 km (18,000-24,000 ft) a.s.l. and drifted NE. A SIGMET notice described an ash plume that rose to altitudes of 9.1-9.8 km (30,000-32,000 ft) a.s.l. on 15 March; ash was not identified in satellite imagery. 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. ==============================================================
