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Smithsonian/USGS Weekly Volcanic Activity Report 15-21 June 2011
From: "Kuhn, Sally" <KUHNS@xxxxxx>
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Smithsonian/USGS Weekly Volcanic Activity Report
15-21 June 2011
Sally Kuhn Sennert - Weekly Report Editor
kuhns@xxxxxx
URL: http://www.volcano.si.edu/reports/usgs/
New Activity/Unrest: | Etna, Sicily (Italy) | Nabro, Eritrea | Puyehue-Cordón Caulle, Central Chile | Turrialba, Costa Rica
Ongoing Activity: | Batu Tara, Komba Island (Indonesia) | Egon, Flores Island (Indonesia) | Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaii (USA) | Paluweh, Lesser Sunda Islands (Indonesia) | Shiveluch, Central Kamchatka (Russia)
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
ETNA Sicily (Italy) 37.734°N, 15.004°E; summit elev. 3330 m
Sezione di Catania - Osservatorio Etneo reported that on 13 June mountain guides heard loud hissing sounds coming from the interior of Etna's Bocca Nuova crater. After nearly six months of quiescence, ash emissions rose from Bocca Nuova the next morning. The emissions were composed of small ash clouds that seemingly originated from the central part of the crater and rose about 200-250 m above the crater rim, then drifted E. Thermal monitoring cameras showed no signs of incandescence in the emissions, which were observed for a few hours before meteorological clouds moved in and prevented further observations. During limited periods of good visibility from 15 to 17 June, sporadic small reddish-to-grayish-brown ash plumes were observed to occur every 5-15 minutes. Usual rhythmic emissions of gas and vapor from the Northeast Crater continued.
Geologic Summary. Mount Etna, towering above Catania, Sicily's second largest city, has one of the world's longest documented records of historical volcanism, dating back to 1500 BC. Historical lava flows cover much of the surface of this massive basaltic stratovolcano, the highest and most voluminous in Italy. Two styles of eruptive activity typically occur at Etna. Persistent explosive eruptions, sometimes with minor lava emissions, take place from one or more of the three prominent summit craters, the Central Crater, NE Crater, and SE Crater. Flank eruptions, typically with higher effusion rates, occur less frequently and originate from fissures that open progressively downward from near the summit. A period of more intense intermittent explosive eruptions from Etna's summit craters began in 1995. The active volcano is monitored by the Instituto Nazionale di Geofisica e Volcanologia (INGV) in Catania.
Source: Sezione di Catania - Osservatorio Etneo http://www.ct.ingv.it/
NABRO Eritrea 13.37°N, 41.70°E; summit elev. 2218 m
An eruption from Nabro that started on 12 June continued to produce a plume. Based on analyses of satellite imagery, the Toulouse VAAC reported that during 15-20 June plumes comprised mostly of water and sulfur dioxide rose to altitudes of 6.1-7.9 km (20,000-26,000 ft) a.s.l. Ash was occasionally detected near the volcano. Satellite imagery posted on MODIS Web showed a dark brown ash plume fanning out to the SW on 19 June. A thermal satellite image acquired at night on 19 June revealed a 15-km-long lava flow that had traveled NW. A high-altitude plume, likely rich in water vapor, rose from the erupting vents and a diffuse ash-rich plume drifted SW.
News articles stated that ash had covered a well-known mine that produces edible salt, and had contaminated food and water sources. During 15-16 June several airlines cancelled some domestic and international flights, including in and out of Addis Abeba (Ethiopia), neighboring Djibouti, and Khartoum (Sudan).
Geologic Summary. The 2218-m-high Nabro stratovolcano is the highest volcano in the Danakil depression of northern Ethiopia and Eritrea. Located at the SE end of the Danakil Alps, Nabro lies in the Danakil horst. Nabro is the most prominent and NE-most of three volcanoes with large summit calderas aligned in a NE-SW direction SW of Dubbi volcano. These three volcanoes, along with Sork Ale volcano, collectively comprise the Bidu volcanic complex. The complex Nabro stratovolcano is truncated by nested calderas, 8 and 5 km in diameter. The larger caldera is widely breached to the SW. Nabro was constructed primarily of trachytic lava flows and pyroclastics. Post-caldera rhyolitic obsidian domes and basaltic lava flows were erupted inside the caldera and on its flanks. Some very recent lava flows were erupted from NNW-trending fissures transverse to the trend of the Nabro volcanic range.
Sources: Toulouse Volcanic Ash Advisory Centre (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/FR/messages.html,
NASA Earth Observatory http://earthobservatory.nasa.gov/,
Addis Fortune http://www.addisfortune.com/Eritrean%20Volcano%20Erupts%20Economic%20Mayhem%20for%20Ethiopia.htm,
Bloomberg http://www.bloomberg.com/news/2011-06-14/ethiopian-airlines-says-flights-disrupted-by-cloud-from-eritrean-volcano.html,
MODIS Rapid Response System http://modis.gsfc.nasa.gov/index.php
PUYEHUE-CORDON CAULLE Central Chile 40.590°S, 72.117°W; summit elev. 2236 m
OVDAS-SERNAGEOMIN reported that the eruption from the Cordón Caulle rift zone, part of the Puyehue-Cordón Caulle volcanic complex, that began on 4 June continued during 15-18 June. The seismic network detected small explosions on 15 June. The eruption plume rose 4-5 km above the crater and drifted SE. The base of the plume was dark gray and ash continued to fall in areas near the volcano. The next day the plume rose 3 km above the crater and was whiter. Satellite imagery showed the plume drifting 1,400 km ESE. On 17 June the plume rose 2 km above the crater and drifted SE. About 5 mm of ash had accumulated in Pajaritos during the night. Ashfall was also reported in eastern areas of Lago Rupanco, about 30 km SSW. According to news articles, plumes from the eruption had circumnavigated the globe, arrived in the W part of Chile (in Coyhaique, 550 km S of the volcano), and again caused domestic flights to be canceled.
On 19 June SERNAGEOMIN noted that meteorological weather prevented clear observations, although a thermal camera used during an overflight showed a thermal anomaly near the emission center. The plume rose 2 km above the crater and drifted SE. A news article stated that authorities lifted the evacuation ban for area residents, allowing them to return home. Articles also stated that flights in South Africa were disrupted during 18-19 June.
SERNAGEOMIN personnel along with regional authorities flew over Puyehue-Cordón Caulle on 20 June. They observed a viscous lava flow with concentric morphology, confirming speculation of magma ascent reflected in seismic data from the previous few days. A 50-m-wide lava flow from the emissions center had traveled 200 m NW and 100 m NE, filling up a depression. A white plume that was gray at the base rose 3-4 km above the crater. Devastated vegetation from pyroclastic flows was observed near the basin of the Nilahue and Abutment rivers. Pulses of tremor were detected by the seismic network. Cameras installed around the volcano showed the plume, which was periodically very dark, rising 5-6 km above the crater. On 21 June the plume rose 3-4 km above the crater and was dark at the base. Although there were no new aerial observations, the seismic signals indicated that the lava flow remained active. News reports noted that flights were again disrupted in parts of Australia on 21 June. SERNAGEOMIN reiterated that the Alert Level remained at 6, Red.
Geologic Summary. The Puyehue-Cordón Caulle volcanic complex (PCCVC) is a large NW-SE-trending late-Pleistocene to Holocene basaltic-to-rhyolitic transverse volcanic chain SE of Lago Ranco. The 1799-m-high Pleistocene Cordillera Nevada caldera lies at the NW end, separated from Puyehue stratovolcano at the SE end by the Cordón Caulle fissure complex. The Pleistocene Mencheca volcano with Holocene flank cones lies NE of Puyehue. The basaltic-to-rhyolitic Puyehue volcano is the most geochemically diverse of the PCCVC. The flat-topped, 2236-m-high Puyehue volcano was constructed above a 5-km-wide caldera and is capped by a 2.4-km-wide summit caldera of Holocene age. Lava flows and domes of mostly rhyolitic composition are found on the eastern flank of Puyehue. Historical eruptions originally attributed to Puyehue, including major eruptions in 1921-22 and 1960, are now known to be from the Cordón Caulle rift zone. The Cordón Caulle geothermal area, occupying a 6 x 13 km wide volcano-tectonic depression, is the largest active geothermal area of the southern Andes volcanic zone.
Sources: Servicio Nacional de Geología y Minería (SERNAGEOMIN) http://www.sernageomin.cl/,
The Telegraph http://www.telegraph.co.uk/news/worldnews/southamerica/chile/8583469/Chilean-ash-cloud-completes-round-the-world-tour.html,
Agence France-Presse http://reliefweb.int/node/421038,
Associated Press http://www.latimes.com/news/la-fgw-south-africa-ash-cloud-20110620,0,2807755.story?track=rss,
Stuff http://www.stuff.co.nz/world/5168548/Ash-cloud-hits-more-Australian-flights
TURRIALBA Costa Rica 10.025°N, 83.767°W; summit elev. 3340 m
OVSICORI-UNA reported that on 9 June scientists conducting fieldwork at Turrialba observed a new crater lake in the W crater, which opened in January 2010 and was the center of the most recent activity. Since February, rock landslides along with abundant mud and clay had accumulated in the bottom of the crater, blocking the vent. Meteoric water from rains starting in May had formed a light-green-colored lake that was 70 by 70 m and about 1 m deep. Minor bubbling in the SW and NE shores was noted, and steam and sulfur dioxide gas emissions rose from many fumarolic vents around the crater.
Geologic Summary. Turrialba, the easternmost of Costa Rica's Holocene volcanoes, is a large vegetated basaltic-to-dacitic stratovolcano located across a broad saddle NE of Irazú volcano overlooking the city of Cartago. The massive 3340-m-high Turrialba is exceeded in height only by Irazú, covers an area of 500 sq km, and is one of Costa Rica's most voluminous volcanoes. Three well-defined craters occur at the upper SW end of a broad 800 x 2200 m wide summit depression that is breached to the NE. Most activity at Turrialba originated from the summit vent complex, but two pyroclastic cones are located on the SW flank. Five major explosive eruptions have occurred at Turrialba during the past 3500 years. Turrialba has been quiescent since a series of explosive eruptions during the 19th century that were sometimes accompanied by pyroclastic flows. Fumarolic activity continues at the central and SW summit craters.
Source: Observatorio Vulcanológico y Sismológico de Costa Rica-Universidad Nacional (OVSICORI-UNA) http://www.ovsicori.una.ac.cr/
Ongoing Activity
BATU TARA Komba Island (Indonesia) 7.792°S, 123.579°E; summit elev. 748 m
Based on analyses of satellite imagery, the Darwin VAAC reported that during 16-20 June ash plumes from Batu Tara rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted 55-75 km W, NW, and N.
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
EGON Flores Island (Indonesia) 8.67°S, 122.45°E; summit elev. 1703 m
CVGHM reported that on 17 June the Alert Level for Egon was lowered to 1 (on a scale of 1-4) because seismicity had decreased and emission heights had been lower since January.
Geologic Summary. Gunung Egon volcano sits astride the narrow waist of eastern Flores Island. The barren, sparsely vegetated summit region has a 350-m-wide, 200-m-deep crater that sometimes contains a lake. Other small crater lakes occur on the flanks of the 1,703-m-high volcano. A lava dome forms the southern 1,671-m-high summit. Reports of historical eruptive activity are inconclusive. A column of "smoke" was often observed above the summit during 1888-1891 and in 1892. Strong "smoke" emission in 1907 reported by Sapper (1917) was considered by the Catalog of Active Volcanoes of the World (Neumann van Padang, 1951) to be an historical eruption, but Kemmerling (1929) noted that this was likely confused with an eruption on the same date and time from Lewotobi Lakilaki volcano.
Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://www.vsi.esdm.go.id/
KARYMSKY Eastern Kamchatka (Russia) 54.05°N, 159.45°E; summit elev. 1536 m
KVERT reported moderate seismic activity at Karymsky during 10-16 June and that possible ash plumes rose to an altitude of 5.5 km (18,000 ft) a.s.l. Satellite imagery showed a weak thermal anomaly on the volcano during 10-14 June and an ash plume that drifted 90 km NE on 14 June. The Aviation 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
KILAUEA Hawaii (USA) 19.421°N, 155.287°W; summit elev. 1222 m
HVO reported that two lava lakes at Kilauea were active during 15-21 June. The level of the summit lava lake fluctuated but remained mostly stable deep in the vent inset within the E wall of Halema'uma'u Crater. A gas plume from the vent drifted SW, depositing variable amounts of ash and fresh spatter nearby. On 17 June a heated brown plume rose from a spattering source on the SE edge of the lake; the ejecta were primarily fresh spatter bits suggesting that the plume derived from a partial collapse of the spattering source or a small rockfall.
At Pu'u 'O'o, lava from vents near the W and NE edges of the perched lava lake in the center of the crater floor continued to fill the lake. The lake level fluctuated and overflowed the edges or flowed through rim breaches, sending lava onto the Pu'u 'O'o crater floor. A small shield had built up against the SW crater wall on the W side of the lake. There was also minor lava activity from at least one source at the base of the SW crater wall.
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/
PALUWEH Lesser Sunda Islands (Indonesia) 8.32°S, 121.708°E; summit elev. 875 m
CVGHM reported that volcanic tremor from Paluweh had not been detected since 1 March 2010 and during January 2011-June solfatara emissions from the summit were not observed. On 17 June, the Alert Level was lowered to 1 (on a scale of 1-4)
Geologic Summary. Paluweh volcano, also known as Rokatenda, forms the 8-km-wide island of Paluweh N of the volcanic arc that cuts across Flores Island. Although the volcano rises about 3,000 m above the sea floor, its summit reaches only 875 m above sea level. The broad irregular summit region contains overlapping craters up to 900 m wide and several lava domes. Several flank vents occur along a NW-trending fissure. The largest historical eruption of Paluweh occurred in 1928, when a strong explosive eruption was accompanied by landslide-induced tsunamis and lava-dome emplacement.
Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://www.vsi.esdm.go.id/
SHIVELUCH Central Kamchatka (Russia) 56.653°N, 161.360°E; summit elev. 3283 m
KVERT reported moderate seismic activity at Shiveluch during 10-16 June and that possible ash plumes rose to an altitude of 10 km (32,800 ft) a.s.l. on 15 June. Satellite imagery showed a gas-and-steam plume drifting 26 km NW on 10 June and a thermal anomaly on the lava dome during 10 and 12-13 June. Meteorological clouds prevented observations on the other days. The Aviation Color Code remained at Orange.
Based on information from KVERT and analyses of satellite imagery, the Tokyo VAAC reported that eruptions on 20 June produced plumes that rose to altitudes of 6.7-10.1 km (22,000-33,000 ft) a.s.l.
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. Intermittent explosive eruptions began in the 1990s from a new lava dome that began growing in 1980. The largest historical eruptions from Shiveluch occurred in 1854 and 1964.
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
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