Smithsonian/USGS Weekly Volcanic Activity Report 18-24 April 2012
From: "Kuhn, Sally" <KUHNS@xxxxxx>
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Smithsonian/USGS Weekly Volcanic Activity Report
18-24 April 2012
Sally Kuhn Sennert - Weekly Report Editor
URL: http://www.volcano.si.edu/reports/usgs/
New Activity/Unrest: | Cleveland, Chuginadak Island | Lamongan, Eastern Java (Indonesia) | Lokon-Empung, Sulawesi | Popocatépetl, México
Ongoing Activity: | Etna, Sicily (Italy) | Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaii (USA) | Nevado del Ruiz, Colombia | Puyehue-Cordón Caulle, Central Chile | Reventador, Ecuador | Santa María, Guatemala | Shiveluch, Central Kamchatka (Russia) | Tungurahua, Ecuador | Villarrica, Central Chile
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
CLEVELAND Chuginadak Island 52.825°N, 169.944°W; summit elev. 1730 m
AVO reported that elevated surface temperatures were observed over Cleveland in satellite imagery during 17-18 April. An explosion on 19 April at 0438, detected by seismometers at Makushin and Okmok volcanoes, generated an ash cloud the rose 4-6 km (13,100-19,700 ft) a.s.l. and drifted S. Satellite images showed block-and-ash deposits extending for up to 1 km down the S flank. A possible weak thermal anomaly was detected in images during 20-21 April.
Geologic Summary. Symmetrical Mount Cleveland stratovolcano is situated at the western end of the uninhabited dumbbell-shaped Chuginadak Island in the east-central Aleutians. The 1,730-m-high stratovolcano is the highest of the Islands of Four Mountains group and is one of the most active in the Aleutians. Numerous large lava flows descend its flanks. It is possible that some 18th to 19th century eruptions attributed to Carlisle (a volcano located across the Carlisle Pass Strait to the NW) should be ascribed to Cleveland. In 1944 Cleveland produced the only known fatality from an Aleutian eruption. Recent eruptions from Mt. Cleveland have been characterized by short-lived explosive ash emissions, at times accompanied by lava fountaining and lava flows down the flanks.
Source: Alaska Volcano Observatory (AVO) http://www.avo.alaska.edu/
LAMONGAN Eastern Java (Indonesia) 7.979°S, 113.342°E; summit elev. 1651 m
CVGHM reported that, although weather conditions often prevented observations of Lamongan during 9 March-17 April, white plumes were occasionally seen rising 10-20 m above the crater rim. Seismicity decreased during this period. CVGHM lowered the Alert Level to 1 (on a scale of 1-4) on 19 April.
Geologic Summary. Lamongan, a small 1,631-m-high stratovolcano located between the massive Tengger and Iyang-Argapura volcanic complexes, is surrounded by numerous maars and cinder cones. The currently active cone has been constructed 650 m to the SW of Gunung Tarub, the volcano's high point. As many as 27 maars with diameters from 150 to 700 m, some containing crater lakes, surround the volcano, along with about 60 cinder cones and spatter cones. Lake-filled maars, including Ranu Pakis, Ranu Klakah, and Ranu Bedali, are located on the eastern and western flanks; dry maars are predominately located on the northern flanks. None of the Lamongan maars has erupted during historical time, although several of the youthful maars cut drainage channels from Gunung Tarub. Lamongan was very active from the time of its first historical eruption in 1799 through the end of the 19th century, producing frequent explosive eruptions and lava flows from vents on the western side of the volcano ranging from the summit to about 450 m elevation.
Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://www.vsi.esdm.go.id/
LOKON-EMPUNG Sulawesi 1.358°N, 124.792°E; summit elev. 1580 m
CVGHM reported that during the morning on 24 April diffuse white plumes rose 25-50 m above Tompaluan crater, in the saddle between the Lokon-Empung peaks. Later that day an eruption was accompanied by loud “thumping” noises heard at local observation posts, though fog prevented views of the crater. The next day diffuse white plumes rose 50-100 m above the crater. The Alert Level remained at 3 (on a scale of 1-4).
Geologic Summary. The twin volcanoes Lokon and Empung, rising about 800 m above the plain of Tondano, are among the most active volcanoes of Sulawesi. Lokon, the higher of the two peaks (whose summits are only 2.2 km apart) has a flat, craterless top. The morphologically younger Empung volcano has a 400-m-wide, 150-m-deep crater that erupted last in the 18th century, but all subsequent eruptions have originated from Tompaluan, a 150 x 250 m wide double crater situated in the saddle between the two peaks. Historical eruptions have primarily produced small-to-moderate ash plumes that have occasionally damaged croplands and houses, but lava-dome growth and pyroclastic flows have also occurred.
Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://www.vsi.esdm.go.id/
POPOCATEPETL México 19.023°N, 98.622°W; summit elev. 5426 m
CENAPRED reported that multiple gas-and-ash plumes rose from Popocatépetl on 18 April; one of the emissions was accompanied by increased incandescence in the crater. An explosion ejected incandescent fragments that landed on the N and NE flanks as far as 800 m from the crater. The fragments landed on snow and generated small lahars. A dense gas, steam, and ash plume drifted E and SE. On 19 April gas-and-ash plumes rose above the crater and drifted ESE, and incandescent fragments rolled 1 km down the flanks. The next day an episode of spasmodic tremor was accompanied by a dense plume of gas, water vapor, and ash that rose 1.5 km and drifted E. During 21-23 April gas-and-steam emissions that sometimes contained small amounts of ash drifted SE, E, and SW. Seismicity was low during 21-22 April and again increased on 23 April. That same day an ash plume drifted NE and incandescent fragments were ejected W. The Alert Level remained at Yellow Phase Three.
Geologic Summary. Popocatépetl, whose name is the Aztec word for smoking mountain, towers to 5,426 m 70 km SE of Mexico City and is North America's second-highest volcano. Frequent historical eruptions have been recorded since the beginning of the Spanish colonial era. A small eruption on 21 December 1994 ended five decades of quiescence. Since 1996 small lava domes have incrementally been constructed within the summit crater and destroyed by explosive eruptions. Intermittent small-to-moderate gas-and-ash eruptions have continued, occasionally producing ashfall in neighboring towns and villages.
Source: Centro Nacional de Prevencion de Desastres (CENAPRED) http://www.cenapred.unam.mx/es/
Ongoing Activity
ETNA Sicily (Italy) 37.734°N, 15.004°E; summit elev. 3330 m
Sezione di Catania - Osservatorio Etneo reported that the twenty-fifth paroxysmal eruptive episode since January 2011 took place at New SE Crater (New SEC) of Etna during the morning of 24 April following about 11 days of quiescence. The episode was characterized by lava fountains, emissions of ash and lapilli, and lava flows that descended the Valle del Bove.
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/index.php
KARYMSKY Eastern Kamchatka (Russia) 54.05°N, 159.45°E; summit elev. 1536 m
KVERT reported that moderate seismic activity from Karymsky continued to be detected during 13-20 April. Satellite imagery showed a thermal anomaly on the volcano during 15-19 April. 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 18-24 April HVO reported that the circulating lava lake periodically rose and fell in the deep pit within Kilauea's Halema'uma'u Crater. Occasional measurements indicated that the gas plume from the vent continued to deposit variable amounts of ash, and occasionally fresh spatter, nearby. Incandescence was visible from both a lava pond in a small pit on the E edge and a small spatter cone on the SE edge of the Pu'u 'O'o crater floor, and on the upper part of the lava-tube system on the E flank. Lava flows continued to advance down the pali and across the coastal plain, reaching about 1.1 km from the coast. During 19-20 April small lava flows issued from a vent on the SE edge of the Pu'u 'O'o crater floor.
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://www.usgs.gov/
NEVADO DEL RUIZ Colombia 4.895°N, 75.322°W; summit elev. 5321 m
According to INGEOMINAS, the Observatorio Vulcanológico and Sismológico de Manizales reported that during 18-19 April multiple seismic signals recorded at Nevado del Ruiz possibly indicated ash emissions, but they could not be verified due to weather conditions. Video data and observers in the city of Manizales (25 km NW) indicated that gas-and-steam plumes rose 900 m above the crater and drifted SE during the morning on 18 April. Satellite imagery detected a steam and sulfur dioxide plume the next day. During 20-24 April high levels of sulfur dioxide were detected in satellite images. Gas-and-steam plumes rose 1-2 km above the crater. The Alert Level remained at II (Orange; "eruption likely within days or weeks").
Geologic Summary. Nevado del Ruiz is a broad, glacier-covered volcano in central Colombia that covers >200 sq km. Three major edifices, composed of andesitic and dacitic lavas and andesitic pyroclastics, have been constructed since the beginning of the Pleistocene. The modern cone consists of a broad cluster of lava domes built within the summit caldera of an older Ruiz volcano. The 1-km-wide, 240-m-deep Arenas crater occupies the summit. Steep headwalls of massive landslides cut the flanks of Nevado del Ruiz. Melting of its summit icecap during historical eruptions, which date back to the 16th century, has resulted in devastating lahars, including one in 1985 that was South America's deadliest eruption.
Source: Instituto Colombiano de Geología y Minería (INGEOMINAS) http://www.ingeominas.gov.co/
PUYEHUE-CORDON CAULLE Central Chile 40.590°S, 72.117°W; summit elev. 2236 m
OVDAS-SERNAGEOMIN reported that, although cloud cover often prevented observations during 17-22 April, satellite and web camera views of the Cordón Caulle rift zone, part of the Puyehue-Cordón Caulle volcanic complex, occasionally showed plumes that rose no higher than 400 m above the crater. Incandescence from the crater was observed during 17-18 and 20-21 April. Due to the low level of activity and decreasing seismicity, the Alert Level was lowered to Yellow on 23 April.
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.
Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN) http://www.sernageomin.cl/index.php
REVENTADOR Ecuador 0.077°S, 77.656°W; summit elev. 3562 m
IG reported that on 18 April a plume with low ash content rose 2 km above Reventador's crater and drifted NW. A steam plume rose 100 m above the crater the next day. Weather conditions prevented observations during 20-23 April.
Geologic Summary. Reventador is the most frequently active of a chain of Ecuadorian volcanoes in the Cordillera Real, well E of the principal volcanic axis. It is a forested stratovolcano that rises above the remote jungles of the western Amazon basin. A 3-km-wide caldera breached to the E was formed by edifice collapse and is partially filled by a young, unvegetated stratovolcano that rises about 1,300 m above the caldera floor. Reventador has been the source of numerous lava flows as well as explosive eruptions that were visible from Quito in historical time. Frequent lahars in this region of heavy rainfall have constructed a debris plain on the eastern floor of the caldera.
Source: Instituto Geofísico-Escuela Politécnica Nacional (IG) http://www.igepn.edu.ec/
SANTA MARIA Guatemala 14.756°N, 91.552°W; summit elev. 3772 m
INSIVUMEH reported that during 22-24 April explosions from Santa María's Santiaguito lava-dome complex generated ash plumes that rose 900 m above the crater and drifted SE. Ash possibly fell in Santa María de Jesus and Calahuache.
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 explosive activity at Shiveluch continued during 13-20 April. Ground-based observers and satellite imagery indicated that a viscous lava flow continued to effuse in the crater formed during a 2010 eruption and was accompanied by fumarolic activity. Observers reported that ash plumes rose to altitudes of 6.5-7.5 km (21,300-24,600 ft) a.s.l. during 16-17 April and to altitudes of 4-5 km (13,100-16,400 ft) a.s.l. on the other days. Satellite imagery showed a weak thermal anomaly daily on the lava dome, and ash plumes that drifted 120 km N, NE, and E during 14-15 and 17-18 April. The Aviation 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. 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.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php
TUNGURAHUA Ecuador 1.467°S, 78.442°W; summit elev. 5023 m
IG reported that on 18 April a plume with low ash content rose 2 km above Tungurahua and drifted NW. Ashfall was reported in Juive (7 km NNW) and Cusúa (7 km NW). The next day, steam rose 1 km above the crater and drifted W, and lahars descended the W and SW flanks. On 20 April steam plumes rose 500-800 m and drifted W. A moderate-sized explosion on 22 April produced "cannon shots" and sounds resembling blocks rolling down the flanks. Rice-sized tephra fell in Pillate (7 km W). Lahars descended the Choglontus (SW), Confesionario (WSW), Romero Ingapirca, and Chontapamba (W) drainages, causing the Baños-Penipe road to close near Chontapamba. On 24 April a steam-and-ash plume rose 2 km above the crater.
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/
VILLARRICA Central Chile 39.42°S, 71.93°W; summit elev. 2847 m
According to Projecto Observación Visual Volcán Villarrica (POVI), an ash plume rose 50 m above Villarrica on 19 April.
Geologic Summary. Villarrica, one of Chile's most active volcanoes, rises above the lake and town of the same name. It is the westernmost of three large stratovolcanoes that trend perpendicular to the Andean chain. A 6-km wide caldera formed during the late Pleistocene, more than 0.9 million years ago. A 2-km-wide postglacial caldera is located at the base of the presently active, dominantly basaltic-to-andesitic cone at the NW margin of the Pleistocene caldera. About 25 scoria cones dot Villarrica's flanks. Plinian eruptions and pyroclastic flows have been produced during the Holocene from this dominantly basaltic volcano, but historical eruptions have consisted largely of mild-to-moderate explosive activity with occasional lava effusion. Lahars from the glacier-covered volcano have damaged towns on its flanks.
Source: Projecto Observación Visual Volcán Villarrica (POVI) http://www.povi.cl/
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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
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