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Smithsonian/USGS Weekly Volcanic Activity Report 16-22 February 2011
From: "Kuhn, Sally" <KUHNS@xxxxxx>
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Smithsonian/USGS Weekly Volcanic Activity Report
16-22 February 2011
Sally Kuhn Sennert - Weekly Report Editor
kuhns@xxxxxx
URL: http://www.volcano.si.edu/reports/usgs/
New Activity/Unrest: | Etna, Sicily (Italy) | Fuego, Guatemala | Kirishima, Kyushu | Santa María, Guatemala | Stromboli, Aeolian Islands (Italy)
Ongoing Activity: | Bulusan, Luzon | Dukono, Halmahera | Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaii (USA) | Kizimen, Eastern Kamchatka (Russia) | Planchón-Peteroa, Central Chile-Argentina border | Sakura-jima, Kyushu | Shiveluch, Central Kamchatka (Russia) | Soufrière Hills, Montserrat | Tengger Caldera, Eastern Java (Indonesia)
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
INGV-CT reported that on 16 February an explosive sequence, presumably from Etna's NE Crater, was detected on 16 February during the late evening. Cloud cover made direct observations difficult. On 18 February the thermal monitoring camera at Montagnola (EMOT) recorded anomalies from the pit crater located on the lower E flank of SE Crater cone. At the same time, the visible-light camera at Montagnola (EMOV) showed intermittent incandescence indicating Strombolian activity, and the seismic network recorded a rapid increase in the volcanic tremor amplitude. This eruptive episode lasted about 11 hours and produced pulsating lava fountains. Lava flows traveled E, following the same path as that of the 12-13 January event, in the direction of the Valle del Bove. Light ashfall occurred on the SW flank of the volcano.
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: Istituto Nazionale di Geofisica e Vulcanologia Sezione di Catania (INGV-CT) http://www.ct.ingv.it/index.php
FUEGO Guatemala 14.473°N, 90.880°W; summit elev. 3763 m
INSIVUMEH reported that during 16-17 and 20-22 February explosions from Fuego produced ash plumes that rose 300-800 m above the crater. Some plumes drifted E. Incandescent material was ejected as high as 100 m above the crater. Avalanches traveled E as well as SW, descending the Taniluyá, Santa Teresa, Ceniza, and Trinidad drainages.
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/
KIRISHIMA Kyushu 31.931°N, 130.864°E; summit elev. 1700 m
Based on reports from JMA, the Tokyo VAAC reported that on 18 February an explosion from Shinmoe-dake (Shinmoe peak), a stratovolcano of the Kirishima volcano group, produced a plume that rose to an altitude of 4.6 km (15,000 ft) a.s.l. and drifted S. A pilot reported that an ash plume rose to an altitude of 5.5 km (18,000 ft) a.s.l. and drifted E. The next day, satellite imagery showed that the ash had dissipated.
According to a news article on 17 February, officials recommended that more than 2,500 residents should evacuate their homes due to potential lahar activity from heavy rain. An official noted that 63 people in Miyakonojo (30 km SE) had already moved to evacuation shelters.
Geologic Summary. Kirishima is a large group of more than 20 Quaternary volcanoes located north of Kagoshima Bay. The late-Pleistocene to Holocene volcano group consists of stratovolcanoes, pyroclastic cones, maars, and underlying shield volcanoes located over an area of 20 x 30 km. The larger stratovolcanoes are scattered throughout the field, with the centrally located, 1,700-m-high Karakuni-dake being the highest. Onami-ike and Mi-ike, the two largest maars, are located SW of Karakuni-dake and at its far eastern end, respectively. Holocene eruptions have been concentrated along an E-W line of vents from Mi-ike to Ohachi, and at Shinmoe-dake to the NE. Frequent small-to-moderate explosive eruptions have been recorded since the 8th century.
Sources: Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html,
Stuff http://www.stuff.co.nz/world/asia/4672853/Volcano-threatens-homes-in-Japan
SANTA MARIA Guatemala 14.756°N, 91.552°W; summit elev. 3772 m
INSIVUMEH reported that during 16-17 February explosions from Santa María's Santiaguito lava dome complex produced ash plumes that rose 800 m above Caliente dome and drifted S and SW. Avalanches traveled S, and ashfall was reported in Palajunoj, on the SW flank. According to the Washington VAAC, ash plumes were observed in satellite imagery drifting more than 10 km SSW. During 18-19 February, thermal anomalies were detected in satellite imagery. An ash plume drifted 25 km W on 18 February and again W at an altitude of 3.4 km (11,000 ft) a.s.l. on 19 February.
INSIVUMEH reported that during 20-21 February activity was low. Explosions produced ash plumes that rose up to 500-900 m above Caliente dome. On 21 February a few avalanches and pyroclastic flows accompanied the explosions. Incandescent avalanches originated from the top of Caliente dome on 22 February.
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
STROMBOLI Aeolian Islands (Italy) 38.789°N, 15.213°E; summit elev. 924 m
INGV-CT reported that on 17 February a series of strong explosions from the northernmost vent of Stromboli's summit area led to the accumulation of hot scoriaceous material on the external N flank of the crater. Activity continued at elevated levels from two vents in the northern portion of the crater terrace through 23 February.
Geologic Summary. Spectacular incandescent nighttime explosions at Stromboli volcano have long attracted visitors to the "Lighthouse of the Mediterranean."Stromboli, the NE-most of the Aeolian Islands, has lent its name to the frequent mild explosive activity that has characterized its eruptions throughout historical time. The small, 926-m-high island of Stromboli is the emergent summit of a volcano that grew in two main eruptive cycles, the last of which formed the western portion of the island. The active summit vents are located at the head of the Sciara del Fuoco, a horseshoe-shaped scarp formed as a result of slope failure that extends to below sea level and funnels pyroclastic ejecta and lava flows to the NW. Essentially continuous mild Strombolian explosions, sometimes accompanied by lava flows, have been recorded at Stromboli since Roman times.
Source: Istituto Nazionale di Geofisica e Vulcanologia Sezione di Catania (INGV-CT) http://www.ct.ingv.it/index.php
Ongoing Activity
BULUSAN Luzon 12.770°N, 124.05°E; summit elev. 1565 m
During 17-20 February, PHIVOLCS reported that up to three daily volcanic earthquakes at Bulusan were detected by the seismic network. Cloud cover mostly prevented observations of the summit area, although steam rose from NW thermal vents on 19 February. An explosion on 21 February produced a gray ash plume that rose 3 km above the crater and drifted SW. Rumbling sounds were heard up to 10 km away in the town of Juban (NW). The event was recorded by the seismic network as an explosion-type earthquake lasting for about 19 minutes. Field investigations confirmed ash deposits in the towns of Irosin (up to 5 mm), 8 km SSW, and Bulan (up to 3 mm), 22 km SW. Traces of ashfall were also reported in the municipalities of Juban and Magallanes (24 km WNW), and in Masbate City (70 km SW), Masbate. According to news articles, about 2,000 people evacuated. During 21-22 February 16 volcanic earthquakes were detected by the seismic network. The Alert Level remained at 1 (on a scale of 0-5).
Geologic Summary. Luzon's southernmost volcano, Bulusan, was constructed within the 11-km-diameter dacitic Irosin caldera, which was formed more than 36,000 years ago. A broad, flat moat is located below the prominent SW caldera rim; the NE rim is buried by the andesitic Bulusan complex. Bulusan is flanked by several other large intracaldera lava domes and cones, including the prominent Mount Jormajan lava dome on the SW flank and Sharp Peak to the NE. The summit of Bulusan volcano is unvegetated and contains a 300-m-wide, 50-m-deep crater. Three small craters are located on the SE flank. Many moderate explosive eruptions have been recorded at Bulusan since the mid-19th century.
Sources: Philippine Institute of Volcanology and Seismology (PHIVOLCS) http://www.phivolcs.dost.gov.ph/index.php,
Xinhua http://www.philstar.com/Article.aspx?articleId=659581&publicationSubCategoryId=200
DUKONO Halmahera 1.68°N, 127.88°E; summit elev. 1335 m
Based on analyses of satellite imagery, the Darwin VAAC reported that during 16-17 February an ash plume from Dukono rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted 150-185 km SW and W.
Geologic Summary. Reports from this remote volcano in northernmost Halmahera are rare, but Dukono has been one of Indonesia's most active volcanoes. More-or-less continuous explosive eruptions, sometimes accompanied by lava flows, occurred from 1933 until at least the mid-1990s, when routine observations were curtailed. During a major eruption in 1550, a lava flow filled in the strait between Halmahera and the N-flank cone of Gunung Mamuya. Dukono is a complex volcano presenting a broad, low profile with multiple summit peaks and overlapping craters. Malupang Wariang, 1 km SW of Dukono's summit crater complex, contains a 700 x 570 m crater that has also been active during historical time.
Source: Darwin Volcanic Ash Advisory Centre (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AU/messages.html
KARYMSKY Eastern Kamchatka (Russia) 54.05°N, 159.45°E; summit elev. 1536 m
KVERT reported that moderate seismic activity was detected at Karymsky during 11-18 February. Seismic data indicated that possible ash plumes rose to an altitude of 4 km (13,100 ft) a.s.l. Satellite imagery showed a daily thermal anomaly and ash plumes that drifted 30 km NE on 16 February. 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
During 16-22 February, activity continued from the summit caldera and east rift zone. At the summit caldera, the level of the circulating lava-pool surface in the deep pit within Halema'uma'u crater fluctuated between 70 and 125 m below the crater floor. Nighttime incandescence was visible from the Jaggar Museum on the NW caldera rim. A plume from the vent drifted in multiple directions and deposited ash and fresh spatter nearby.
At the east rift zone, two branches of the 29 November lava flow (a lava tube breach at 366 m elevation) produced scattered surface flows on the pali and coastal plain. In Pu'u 'O'o crater, lava effused from a cone on the NE portion of the crater floor and from a vent in the E crater wall during most of 16-18 February, covering a large portion of the crater floor. After the lava effusion ceased, incandescence emanated from the cone and vent.
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/
KIZIMEN Eastern Kamchatka (Russia) 55.130°N, 160.32°E; summit elev. 2376 m
KVERT reported that during 11-18 February seismicity from Kizimen was high but variable, and many shallow volcanic earthquakes as well as volcanic tremor continued to be detected. Satellite images showed a bright thermal anomaly over the volcano daily. During 12-17 February ash plumes drifted more than 170 km E. The Aviation Color Code remained at Orange.
The Tokyo VAAC reported that on 22 February a possible eruption detected in satellite imagery produced a plume that rose to an altitude of 2.7 km (9,000 ft) a.s.l. and drifted E. Subsequent notices stated that ash emissions had continued then dissipated later that day.
Geologic Summary. Kizimen is an isolated, conical stratovolcano that is morphologically similar to Mount St. Helens prior to its 1980 eruption. The summit of Kizimen consists of overlapping lava domes, and blocky lava flows descend the flanks of the volcano, which is the westernmost of a volcanic chain north of Kronotsky volcano. The 2,376-m-high Kizimen was formed during four eruptive cycles beginning about 12,000 years ago and lasting 2,000-3,500 years. The largest eruptions took place about 10,000 and 8300-8400 years ago, and three periods of longterm lava-dome growth have occurred. The latest eruptive cycle began about 3,000 years ago with a large explosion and was followed by lava-dome growth lasting intermittently about 1,000 years. An explosive eruption about 1,100 years ago produced a lateral blast and created a 1.0 x 0.7 km wide crater breached to the NE, inside which a small lava dome (the fourth at Kizimen) has grown. A single explosive eruption, during 1927-28, has been recorded in historical time.
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
PLANCHON-PETEROA Central Chile-Argentina border 35.240°S, 70.570°W; summit elev. 4107 m
Based on SIGMET notices, the Buenos Aires VAAC reported that on 17 February an ash plume from Planchón-Peteroa rose to altitudes of 3-4.3 km (10,000-14,000 ft) a.s.l. and drifted SE.
Geologic Summary. Planchón-Peteroa is an elongated complex volcano along the Chile-Argentina border with several overlapping calderas. Activity began in the Pleistocene with construction of the basaltic-andesite to dacitic Volcán Azufre, followed by formation of basaltic and basaltic-andesite Volcán Planchón, 6 km to the N. About 11,500 years ago, much of Azufre and part of Planchón collapsed, forming the massive Río Teno debris avalanche, which reached Chile's Central Valley. Subsequently, Volcán Planchón II was formed. The youngest volcano, andesitic and basaltic-andesite Volcá Peteroa, consists of scattered vents between Azufre and Planchón. Peteroa has been active into historical time and contains a small steaming crater lake. Historical eruptions from the Planchón-Peteroa complex have been dominantly explosive, although lava flows were erupted in 1837 and 1937.
Source: Buenos Aires Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AG/messages.html
SAKURA-JIMA Kyushu 31.585°N, 130.657°E; summit elev. 1117 m
Based on information from JMA, the Tokyo VAAC reported that during 16-17 and 19-22 February explosions from Sakura-jima sometimes produced plumes that rose to altitudes of 1.8-2.4 km (6,000-8,000 ft) a.s.l. Some plumes drifted W, SW, and ESE. During 21-22 February, pilots reported that ash plumes rose to altitudes of 2.4-2.7-3 km (8,000-9,000 ft) a.s.l.
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.
Source: Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html
SHIVELUCH Central Kamchatka (Russia) 56.653°N, 161.360°E; summit elev. 3283 m
KVERT reported that moderate seismic activity was detected at Shiveluch during 11-18 February. A thermal anomaly over the lava dome was observed daily in satellite imagery. Gas and steam activity was observed on 13 and 16 February. The Aviation Color Code remained at Orange. The Tokyo VAAC reported that on 22 February a possible eruption detected in satellite imagery produced a plume that rose to an altitude of 3.4 km (11,000 ft) a.s.l. and drifted NE. Subsequent notices that day stated that ash had dissipated.
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
SOUFRIERE HILLS Montserrat 16.72°N, 62.18°W; summit elev. 915 m
MVO reported that on 15 February clear views of the Soufrière Hills lava dome allowed scientists to conduct a thermal survey, the first since 2 December 2010, and compare the results to identify changes. A warmer area on the W side of the lava dome (Gages) had moved upslope. This area had been the source of a number of pyroclastic flows and rockfalls since February 2010. The second difference was the apparent increase in the number of fumaroles inside the collapse scar and around the 2006-2007 dome. One of the most obvious areas of increase was on the NE side of the lava dome.
MVO also reported that in total 18 volcano-tectonic earthquakes from Soufrière Hills were detected in two swarms that occurred on 12 and 16 February. Brief clear views of the lava dome revealed no significant morphological changes. Fresh pyroclastic-flow deposits on the E side of the dome at the head of the Tar River valley were noted. The Hazard Level remained at 3.
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/
TENGGER CALDERA Eastern Java (Indonesia) 7.942°S, 112.95°E; summit elev. 2329 m
CVGHM reported that during 17-18 February brownish gray ash plumes from Tengger Caldera's Bromo cone rose 400-800 m above the crater and drifted ENE. Incandescent material was ejected 300 m above the crater and landed as far as 500 m away, and roaring and booming was heard. The Alert Level remained at 3 (on a scale of 1-4). Residents and tourists were not permitted within a 2-km-radius of the active crater.
Geologic Summary. The 16-km-wide Tengger caldera in eastern Java is located at the northern end of a volcanic massif extending from Semeru volcano. The massive Tengger volcanic complex consists of five overlapping stratovolcanoes, each truncated by a caldera. The most recent is the 9 x 10 km wide Sandsea caldera, which formed incrementally during the late Pleistocene and early Holocene. An overlapping cluster of post-caldera cones was constructed on the floor of the Sandsea caldera within the past several thousand years. The youngest of these is Bromo, one of Java's most frequently visited and most active volcanoes. More than 50 mild-to-moderate explosive eruptions have occurred since 1804.
Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://www.vsi.esdm.go.id/
16-22 February 2011
Sally Kuhn Sennert - Weekly Report Editor
kuhns@xxxxxx
URL: http://www.volcano.si.edu/reports/usgs/
New Activity/Unrest: | Etna, Sicily (Italy) | Fuego, Guatemala | Kirishima, Kyushu | Santa María, Guatemala | Stromboli, Aeolian Islands (Italy)
Ongoing Activity: | Bulusan, Luzon | Dukono, Halmahera | Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaii (USA) | Kizimen, Eastern Kamchatka (Russia) | Planchón-Peteroa, Central Chile-Argentina border | Sakura-jima, Kyushu | Shiveluch, Central Kamchatka (Russia) | Soufrière Hills, Montserrat | Tengger Caldera, Eastern Java (Indonesia)
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
INGV-CT reported that on 16 February an explosive sequence, presumably from Etna's NE Crater, was detected on 16 February during the late evening. Cloud cover made direct observations difficult. On 18 February the thermal monitoring camera at Montagnola (EMOT) recorded anomalies from the pit crater located on the lower E flank of SE Crater cone. At the same time, the visible-light camera at Montagnola (EMOV) showed intermittent incandescence indicating Strombolian activity, and the seismic network recorded a rapid increase in the volcanic tremor amplitude. This eruptive episode lasted about 11 hours and produced pulsating lava fountains. Lava flows traveled E, following the same path as that of the 12-13 January event, in the direction of the Valle del Bove. Light ashfall occurred on the SW flank of the volcano.
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: Istituto Nazionale di Geofisica e Vulcanologia Sezione di Catania (INGV-CT) http://www.ct.ingv.it/index.php
FUEGO Guatemala 14.473°N, 90.880°W; summit elev. 3763 m
INSIVUMEH reported that during 16-17 and 20-22 February explosions from Fuego produced ash plumes that rose 300-800 m above the crater. Some plumes drifted E. Incandescent material was ejected as high as 100 m above the crater. Avalanches traveled E as well as SW, descending the Taniluyá, Santa Teresa, Ceniza, and Trinidad drainages.
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/
KIRISHIMA Kyushu 31.931°N, 130.864°E; summit elev. 1700 m
Based on reports from JMA, the Tokyo VAAC reported that on 18 February an explosion from Shinmoe-dake (Shinmoe peak), a stratovolcano of the Kirishima volcano group, produced a plume that rose to an altitude of 4.6 km (15,000 ft) a.s.l. and drifted S. A pilot reported that an ash plume rose to an altitude of 5.5 km (18,000 ft) a.s.l. and drifted E. The next day, satellite imagery showed that the ash had dissipated.
According to a news article on 17 February, officials recommended that more than 2,500 residents should evacuate their homes due to potential lahar activity from heavy rain. An official noted that 63 people in Miyakonojo (30 km SE) had already moved to evacuation shelters.
Geologic Summary. Kirishima is a large group of more than 20 Quaternary volcanoes located north of Kagoshima Bay. The late-Pleistocene to Holocene volcano group consists of stratovolcanoes, pyroclastic cones, maars, and underlying shield volcanoes located over an area of 20 x 30 km. The larger stratovolcanoes are scattered throughout the field, with the centrally located, 1,700-m-high Karakuni-dake being the highest. Onami-ike and Mi-ike, the two largest maars, are located SW of Karakuni-dake and at its far eastern end, respectively. Holocene eruptions have been concentrated along an E-W line of vents from Mi-ike to Ohachi, and at Shinmoe-dake to the NE. Frequent small-to-moderate explosive eruptions have been recorded since the 8th century.
Sources: Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html,
Stuff http://www.stuff.co.nz/world/asia/4672853/Volcano-threatens-homes-in-Japan
SANTA MARIA Guatemala 14.756°N, 91.552°W; summit elev. 3772 m
INSIVUMEH reported that during 16-17 February explosions from Santa María's Santiaguito lava dome complex produced ash plumes that rose 800 m above Caliente dome and drifted S and SW. Avalanches traveled S, and ashfall was reported in Palajunoj, on the SW flank. According to the Washington VAAC, ash plumes were observed in satellite imagery drifting more than 10 km SSW. During 18-19 February, thermal anomalies were detected in satellite imagery. An ash plume drifted 25 km W on 18 February and again W at an altitude of 3.4 km (11,000 ft) a.s.l. on 19 February.
INSIVUMEH reported that during 20-21 February activity was low. Explosions produced ash plumes that rose up to 500-900 m above Caliente dome. On 21 February a few avalanches and pyroclastic flows accompanied the explosions. Incandescent avalanches originated from the top of Caliente dome on 22 February.
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
STROMBOLI Aeolian Islands (Italy) 38.789°N, 15.213°E; summit elev. 924 m
INGV-CT reported that on 17 February a series of strong explosions from the northernmost vent of Stromboli's summit area led to the accumulation of hot scoriaceous material on the external N flank of the crater. Activity continued at elevated levels from two vents in the northern portion of the crater terrace through 23 February.
Geologic Summary. Spectacular incandescent nighttime explosions at Stromboli volcano have long attracted visitors to the "Lighthouse of the Mediterranean."Stromboli, the NE-most of the Aeolian Islands, has lent its name to the frequent mild explosive activity that has characterized its eruptions throughout historical time. The small, 926-m-high island of Stromboli is the emergent summit of a volcano that grew in two main eruptive cycles, the last of which formed the western portion of the island. The active summit vents are located at the head of the Sciara del Fuoco, a horseshoe-shaped scarp formed as a result of slope failure that extends to below sea level and funnels pyroclastic ejecta and lava flows to the NW. Essentially continuous mild Strombolian explosions, sometimes accompanied by lava flows, have been recorded at Stromboli since Roman times.
Source: Istituto Nazionale di Geofisica e Vulcanologia Sezione di Catania (INGV-CT) http://www.ct.ingv.it/index.php
Ongoing Activity
BULUSAN Luzon 12.770°N, 124.05°E; summit elev. 1565 m
During 17-20 February, PHIVOLCS reported that up to three daily volcanic earthquakes at Bulusan were detected by the seismic network. Cloud cover mostly prevented observations of the summit area, although steam rose from NW thermal vents on 19 February. An explosion on 21 February produced a gray ash plume that rose 3 km above the crater and drifted SW. Rumbling sounds were heard up to 10 km away in the town of Juban (NW). The event was recorded by the seismic network as an explosion-type earthquake lasting for about 19 minutes. Field investigations confirmed ash deposits in the towns of Irosin (up to 5 mm), 8 km SSW, and Bulan (up to 3 mm), 22 km SW. Traces of ashfall were also reported in the municipalities of Juban and Magallanes (24 km WNW), and in Masbate City (70 km SW), Masbate. According to news articles, about 2,000 people evacuated. During 21-22 February 16 volcanic earthquakes were detected by the seismic network. The Alert Level remained at 1 (on a scale of 0-5).
Geologic Summary. Luzon's southernmost volcano, Bulusan, was constructed within the 11-km-diameter dacitic Irosin caldera, which was formed more than 36,000 years ago. A broad, flat moat is located below the prominent SW caldera rim; the NE rim is buried by the andesitic Bulusan complex. Bulusan is flanked by several other large intracaldera lava domes and cones, including the prominent Mount Jormajan lava dome on the SW flank and Sharp Peak to the NE. The summit of Bulusan volcano is unvegetated and contains a 300-m-wide, 50-m-deep crater. Three small craters are located on the SE flank. Many moderate explosive eruptions have been recorded at Bulusan since the mid-19th century.
Sources: Philippine Institute of Volcanology and Seismology (PHIVOLCS) http://www.phivolcs.dost.gov.ph/index.php,
Xinhua http://www.philstar.com/Article.aspx?articleId=659581&publicationSubCategoryId=200
DUKONO Halmahera 1.68°N, 127.88°E; summit elev. 1335 m
Based on analyses of satellite imagery, the Darwin VAAC reported that during 16-17 February an ash plume from Dukono rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted 150-185 km SW and W.
Geologic Summary. Reports from this remote volcano in northernmost Halmahera are rare, but Dukono has been one of Indonesia's most active volcanoes. More-or-less continuous explosive eruptions, sometimes accompanied by lava flows, occurred from 1933 until at least the mid-1990s, when routine observations were curtailed. During a major eruption in 1550, a lava flow filled in the strait between Halmahera and the N-flank cone of Gunung Mamuya. Dukono is a complex volcano presenting a broad, low profile with multiple summit peaks and overlapping craters. Malupang Wariang, 1 km SW of Dukono's summit crater complex, contains a 700 x 570 m crater that has also been active during historical time.
Source: Darwin Volcanic Ash Advisory Centre (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AU/messages.html
KARYMSKY Eastern Kamchatka (Russia) 54.05°N, 159.45°E; summit elev. 1536 m
KVERT reported that moderate seismic activity was detected at Karymsky during 11-18 February. Seismic data indicated that possible ash plumes rose to an altitude of 4 km (13,100 ft) a.s.l. Satellite imagery showed a daily thermal anomaly and ash plumes that drifted 30 km NE on 16 February. 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
During 16-22 February, activity continued from the summit caldera and east rift zone. At the summit caldera, the level of the circulating lava-pool surface in the deep pit within Halema'uma'u crater fluctuated between 70 and 125 m below the crater floor. Nighttime incandescence was visible from the Jaggar Museum on the NW caldera rim. A plume from the vent drifted in multiple directions and deposited ash and fresh spatter nearby.
At the east rift zone, two branches of the 29 November lava flow (a lava tube breach at 366 m elevation) produced scattered surface flows on the pali and coastal plain. In Pu'u 'O'o crater, lava effused from a cone on the NE portion of the crater floor and from a vent in the E crater wall during most of 16-18 February, covering a large portion of the crater floor. After the lava effusion ceased, incandescence emanated from the cone and vent.
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/
KIZIMEN Eastern Kamchatka (Russia) 55.130°N, 160.32°E; summit elev. 2376 m
KVERT reported that during 11-18 February seismicity from Kizimen was high but variable, and many shallow volcanic earthquakes as well as volcanic tremor continued to be detected. Satellite images showed a bright thermal anomaly over the volcano daily. During 12-17 February ash plumes drifted more than 170 km E. The Aviation Color Code remained at Orange.
The Tokyo VAAC reported that on 22 February a possible eruption detected in satellite imagery produced a plume that rose to an altitude of 2.7 km (9,000 ft) a.s.l. and drifted E. Subsequent notices stated that ash emissions had continued then dissipated later that day.
Geologic Summary. Kizimen is an isolated, conical stratovolcano that is morphologically similar to Mount St. Helens prior to its 1980 eruption. The summit of Kizimen consists of overlapping lava domes, and blocky lava flows descend the flanks of the volcano, which is the westernmost of a volcanic chain north of Kronotsky volcano. The 2,376-m-high Kizimen was formed during four eruptive cycles beginning about 12,000 years ago and lasting 2,000-3,500 years. The largest eruptions took place about 10,000 and 8300-8400 years ago, and three periods of longterm lava-dome growth have occurred. The latest eruptive cycle began about 3,000 years ago with a large explosion and was followed by lava-dome growth lasting intermittently about 1,000 years. An explosive eruption about 1,100 years ago produced a lateral blast and created a 1.0 x 0.7 km wide crater breached to the NE, inside which a small lava dome (the fourth at Kizimen) has grown. A single explosive eruption, during 1927-28, has been recorded in historical time.
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
PLANCHON-PETEROA Central Chile-Argentina border 35.240°S, 70.570°W; summit elev. 4107 m
Based on SIGMET notices, the Buenos Aires VAAC reported that on 17 February an ash plume from Planchón-Peteroa rose to altitudes of 3-4.3 km (10,000-14,000 ft) a.s.l. and drifted SE.
Geologic Summary. Planchón-Peteroa is an elongated complex volcano along the Chile-Argentina border with several overlapping calderas. Activity began in the Pleistocene with construction of the basaltic-andesite to dacitic Volcán Azufre, followed by formation of basaltic and basaltic-andesite Volcán Planchón, 6 km to the N. About 11,500 years ago, much of Azufre and part of Planchón collapsed, forming the massive Río Teno debris avalanche, which reached Chile's Central Valley. Subsequently, Volcán Planchón II was formed. The youngest volcano, andesitic and basaltic-andesite Volcá Peteroa, consists of scattered vents between Azufre and Planchón. Peteroa has been active into historical time and contains a small steaming crater lake. Historical eruptions from the Planchón-Peteroa complex have been dominantly explosive, although lava flows were erupted in 1837 and 1937.
Source: Buenos Aires Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AG/messages.html
SAKURA-JIMA Kyushu 31.585°N, 130.657°E; summit elev. 1117 m
Based on information from JMA, the Tokyo VAAC reported that during 16-17 and 19-22 February explosions from Sakura-jima sometimes produced plumes that rose to altitudes of 1.8-2.4 km (6,000-8,000 ft) a.s.l. Some plumes drifted W, SW, and ESE. During 21-22 February, pilots reported that ash plumes rose to altitudes of 2.4-2.7-3 km (8,000-9,000 ft) a.s.l.
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.
Source: Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html
SHIVELUCH Central Kamchatka (Russia) 56.653°N, 161.360°E; summit elev. 3283 m
KVERT reported that moderate seismic activity was detected at Shiveluch during 11-18 February. A thermal anomaly over the lava dome was observed daily in satellite imagery. Gas and steam activity was observed on 13 and 16 February. The Aviation Color Code remained at Orange. The Tokyo VAAC reported that on 22 February a possible eruption detected in satellite imagery produced a plume that rose to an altitude of 3.4 km (11,000 ft) a.s.l. and drifted NE. Subsequent notices that day stated that ash had dissipated.
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
SOUFRIERE HILLS Montserrat 16.72°N, 62.18°W; summit elev. 915 m
MVO reported that on 15 February clear views of the Soufrière Hills lava dome allowed scientists to conduct a thermal survey, the first since 2 December 2010, and compare the results to identify changes. A warmer area on the W side of the lava dome (Gages) had moved upslope. This area had been the source of a number of pyroclastic flows and rockfalls since February 2010. The second difference was the apparent increase in the number of fumaroles inside the collapse scar and around the 2006-2007 dome. One of the most obvious areas of increase was on the NE side of the lava dome.
MVO also reported that in total 18 volcano-tectonic earthquakes from Soufrière Hills were detected in two swarms that occurred on 12 and 16 February. Brief clear views of the lava dome revealed no significant morphological changes. Fresh pyroclastic-flow deposits on the E side of the dome at the head of the Tar River valley were noted. The Hazard Level remained at 3.
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/
TENGGER CALDERA Eastern Java (Indonesia) 7.942°S, 112.95°E; summit elev. 2329 m
CVGHM reported that during 17-18 February brownish gray ash plumes from Tengger Caldera's Bromo cone rose 400-800 m above the crater and drifted ENE. Incandescent material was ejected 300 m above the crater and landed as far as 500 m away, and roaring and booming was heard. The Alert Level remained at 3 (on a scale of 1-4). Residents and tourists were not permitted within a 2-km-radius of the active crater.
Geologic Summary. The 16-km-wide Tengger caldera in eastern Java is located at the northern end of a volcanic massif extending from Semeru volcano. The massive Tengger volcanic complex consists of five overlapping stratovolcanoes, each truncated by a caldera. The most recent is the 9 x 10 km wide Sandsea caldera, which formed incrementally during the late Pleistocene and early Holocene. An overlapping cluster of post-caldera cones was constructed on the floor of the Sandsea caldera within the past several thousand years. The youngest of these is Bromo, one of Java's most frequently visited and most active volcanoes. More than 50 mild-to-moderate explosive eruptions have occurred since 1804.
Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://www.vsi.esdm.go.id/
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