Sunday, February 26, 2012

[ Volcano ] Smithsonian/USGS Weekly Volcanic Activity Report 18-24 January 2012

Smithsonian/USGS Weekly Volcanic Activity Report 18-24 January 2012
From: "Faulk, Elisabeth" <>

Smithsonian/USGS Weekly Volcanic Activity Report

18-24 January 2012

Elisabeth Faulk - Weekly Report Editor


New Activity/Unrest: | Sangay, Ecuador | Tungurahua, Ecuador | Turrialba, Costa Rica

Ongoing Activity: | Fuego, Guatemala | Hierro, Canary Islands (Spain) | Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaii (USA) | Kizimen, Eastern Kamchatka (Russia) | Popocatépetl, México | Puyehue-Cordón Caulle, Central Chile | Sakura-jima, Kyushu | Santa María, Guatemala | Shiveluch, Central Kamchatka (Russia)

This page is updated on Wednesdays. Please see the GVP Home Page for news of the latest significant activity.

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

SANGAY Ecuador 2.002°S, 78.341°W; summit elev. 5230 m

Based on information from pilots and the Guayaquil MWO, an ash plume from Sangay was reported drifting S and SE on 23 January. Ash was not detected in partly-cloudy satellite imagery. On 24 January a hotspot was visible on satellite imagery.

Geologic Summary. The isolated Sangay volcano, located E of the Andean crest, is the southernmost of Ecuador's volcanoes, and its most active. It has been in frequent eruption for the past several centuries. The steep-sided, 5,230-m-high glacier-covered volcano grew within horseshoe-shaped calderas of two previous edifices, which were destroyed by collapse to the E, producing large debris avalanches that reached the Amazonian lowlands. The modern edifice dates back to at least 14,000 years ago. Sangay towers above the tropical jungle on the E side; on the other sides flat plains of ash from the volcano have been sculpted by heavy rains into steep-walled canyons up to 600 m deep. The earliest report of an historical eruption was in 1628. More or less continuous eruptions were reported from 1728 until 1916, and again from 1934 to the present. The more or less constant eruptive activity has caused frequent changes to the morphology of the summit crater complex.

Source: Washington Volcanic Ash Advisory Center (VAAC)

TUNGURAHUA Ecuador 1.467°S, 78.442°W; summit elev. 5023 m

IG reported that during 17-22 January low-level seismic activity was detected at Tungurahua and cloud cover mostly prevented observations. On 17 and 20 January steam plumes rose 500 m above the crater. Muddy water in the Achupashal and Pirámide drainages on the NW flanks was noted on 20 January, and a lahar traveled down the Pampas drainage on 21 January. Seismic activity slightly increased during 23-24 January.

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)

TURRIALBA Costa Rica 10.025°N, 83.767°W; summit elev. 3340 m

OVSICORI-UNA reported that on 12 January a new vent opened on the SE flank of the W crater of Turrialba and ash emissions drifted NNE; ashfall was reported in Tres Ríos (27 km SW). During the evening of 18 January scientists observed gas emissions and ejection of tephra from the vent. They also observed reddish flames from combusting gas, estimated to be about 700 degrees Celsius. Residents reported a dark ash cloud and ashfall in La Central (4 km SW). An OVSICORI-UNA pilot observed an ash plume that rose to altitudes of 4.3-6.1 km (14,000-20,000 ft) a.s.l. on 18 January.

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)

Ongoing Activity

FUEGO Guatemala 14.473°N, 90.880°W; summit elev. 3763 m

INSIVUMEH reported that during 18-19 and 23-24 January explosions from Fuego generated ash plumes that rose 200-700 m above the crater; the plumes drifted 8-15 km S, SW, and W. During 18-19 January incandescent material rose as high as 100 m above the crater and at night on 23 January incandescent explosions were observed. Block avalanches descended the S flanks.

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)

HIERRO Canary Islands (Spain) 27.73°N, 18.03°W; summit elev. 1500 m

Instituto Geográfico Nacional (IGN) reported that during 18-24 January the submarine eruption continued S of El Hierro Island. Mean tremor amplitude has oscillated considerably since 19 January, including abrupt changes from rather high values to periods of almost no tremor which lasted a few hours.  Emissions of large steaming lava fragments were observed every day of this report period.

Thirty-two seismic events were registered during this period, most of them located in the central part of the island, extending offshore to the S, at depths between 8 and 19 km with a maximum magnitude of 2.2. Analyses of GPS deformation showed stability both in vertical and horizontal components.

Geologic Summary. The triangular island of Hierro is the SW-most and least studied of the Canary Islands. The massive Hierro shield volcano is truncated by a large NW-facing escarpment formed as a result of gravitational collapse of El Golfo volcano about 130,000 years ago. The steep-sided 1500-m-high scarp towers above a low lava platform bordering 12-km-wide El Golfo Bay, and three other large submarine landslide deposits occur to the SW and SE. Three prominent rifts oriented NW, NE, and south at 120 degree angles form prominent topographic ridges. The subaerial portion of the volcano consists of flat-lying Quaternary basaltic and trachybasaltic lava flows and tuffs capped by numerous young cinder cones and lava flows. Holocene cones and flows are found both on the outer flanks and in the El Golfo depression. Hierro contains the greatest concentration of young vents in the Canary Islands. Uncertainty surrounds the report of an historical eruption in 1793.

Source: Instituto Geográfico Nacional (IGN)

KARYMSKY Eastern Kamchatka (Russia) 54.05°N, 159.45°E; summit elev. 1536 m

KVERT reported that seismic activity continued at a moderate level at Karymsky during 13-20 January and that seismicity indicated the possibility of ash plumes to an altitude of 3.3 km (10,800 ft) a.s.l. Satellite imagery showed a thermal anomaly at the volcano during 14-15 January; clouds prevented views on the other days. 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)

KILAUEA Hawaii (USA) 19.421°N, 155.287°W; summit elev. 1222 m

During 18-24 January, HVO reported that the lava lake circulated and periodically rose and fell in the deep pit within Kilauea's Halema'uma'u Crater, remaining below the inner ledge (75 m below the crater floor). Almost daily measurements indicated that the gas plume from the vent continued to deposit variable amounts of ash and fresh spatter nearby.

Incandescence was visible on the NE, SE, and W edges of the Pu'u 'O'o crater floor during 18-24 January. Incandescence emanated both from small lava flows which had issued from the NE and SE sources on 18 January, and from a long narrow lava flow that traveled W across the crater floor on 20 January. Minor surface flows were observed in satellite imagery on the upper flow field on 18 January, and during 19-23 January, small thermal anomalies were seen in satellite imagery on the upper E rift zone. Scientists on an overflight reported small active pahoehoe lobes about 4 km SE of the Pu'u 'O'o cone on 21 January.

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)

KIZIMEN Eastern Kamchatka (Russia) 55.130°N, 160.32°E; summit elev. 2376 m

KVERT reported moderate seismic activity at Kizimen during 13-20 January and a large thermal anomaly that was detected daily in satellite images. Video and satellite observations indicated both continued effusion of a large lava flow on the E flank and accompanying hot avalanches. Video data showed strong gas-and-steam activity all week. The Aviation Color Code remained at Orange.

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, ha
 s been recorded in historical time.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

POPOCATEPETL México 19.023°N, 98.622°W; summit elev. 5426 m

CENAPRED reported that during 18-24 January steam-and-gas emissions rose from Popocatépetl, that occasionally contained small amounts of ash during 19-22 January. On 19 January a plume rose 2.5 km above the crater and drifted NE. Crater incandescence was observed at night during 19-21 January.

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)

PUYEHUE-CORDON CAULLE Central Chile 40.590°S, 72.117°W; summit elev. 2236 m

Based on seismicity detected during 18-23 January OVDAS-SERNAGEOMIN reported that the eruption from the Cordón Caulle rift zone, part of the Puyehue-Cordón Caulle volcanic complex, continued at a low level. On 18, 20, and 22-23 January plumes observed with a web camera rose 2.5-7 km above the crater and satellite images showed ash plumes drifting 25-110 km NE, E, SE, and W. The Alert Level remained at 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 volc
 ano-tectonic depression, is the largest active geothermal area of the southern Andes volcanic zone.

Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN)

SAKURA-JIMA Kyushu 31.585°N, 130.657°E; summit elev. 1117 m

Based on information from JMA, the Tokyo VAAC reported that during 18-24 January explosions from Sakura-jima produced plumes that rose to altitudes of 1.5-2.7 km (5,000-9,000 ft) a.s.l. and drifted N, NE, E, and SE. On 20 January a pilot observed an ash plume that rose to an altitude of 1.8 km (6,000 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)

SANTA MARIA Guatemala 14.756°N, 91.552°W; summit elev. 3772 m

INSIVUMEH reported that active lava flows on the SE flanks of Santa María's Santiaguito lava-dome complex generated block avalanches during 18-19 and 23 January. On 19 and 23 January explosions generated ash plumes that rose 400-800 m above the complex. On 19 January ashfall was reported in communities of La Florida (5 km S), Palajunoj (SW flank), and San Marcos (46 km NW). Crater incandescence was observed at night on 23 January.

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.

Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)

SHIVELUCH Central Kamchatka (Russia) 56.653°N, 161.360°E; summit elev. 3283 m

KVERT reported that low levels of seismic activity were detected at Shiveluch during 13-20 January, and on 14 January ash plumes were observed. Satellite imagery showed a thermal anomaly over the lava dome every day except on 16 January. Ground-based observers noted that a viscous lava flow continued to effuse in the crater that was formed during a 2010 eruption and hot avalanches from the lava flow were occasionally observed at night with a web camera. Moderate fumarolic activity at the lava dome was observed during 13-14 and 17-18 January. The Aviation Color Code remained at Orange.

Based on satellite observations, the Tokyo VAAC reported that on 22 January a possible eruption produced a plume that rose to an altitude of 4.6 km (15,000 ft) a.s.l. and drifted NW; subsequent satellite images showed that ash was present. Based on information from satellite images and KVERT, ash plumes rose to an altitude of 5.2 km (17,000 ft) a.s.l. on 23 January and dissipated the next day.

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), Tokyo Volcanic Ash Advisory Center (VAAC)


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