November 23-29, 2011

The following reports are provided courtesy of the Smithsonian’s Global Volcanism Program and the US Geological Survey’s Volcano Hazards Program.

You can view their full reports with loads of additional background information at http://www.volcano.si.edu/reports/usgs/

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GALERAS Colombia 1.22°N, 77.37°W; summit elev. 4276 m

INGEOMINAS reported that during 15-22 November steam from Galeras rose from the main crater, two craters to the N and SW (Paisita and Chavas, respectively), and a crack on the N flank of the active cone. Seismicity was at low levels, although some earthquakes were characterized as “tornillo-type.” During 23-24 November the seismic network detected an emerging seismic pattern of “tornillo-type” earthquakes similar to patterns detected prior to past eruptions. Gas emissions also decreased. INGEOMINAS raised the Alert Level to II (Orange; “probable eruption in term of days or weeks”) on 24 November.

Source: Instituto Colombiano de Geología y Minería (INGEOMINAS)

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

IG reported that increased seismicity from Tungurahua was detected at 1540 on 27 November, and at 1650 the seismic network recorded four volcano-tectonic earthquakes. Two small explosions at 1701 and 1705 were followed by a large explosion at 1718. Pyroclastic flows descended the Achupashal, Chotanpamba, and Mandur drainages on the NW and W flanks. Two more large explosions were detected at 1731 and 1735. Incandescentblocks traveled 1 km down the flanks, and roaring noises and sounds resembling “cannon shots” were reported. Ashfall was reported in Manzano (8 km SW), Bilbao (8 km W), and Pillate (8 km W), ash and tephra fell in Cotaló (8 km NW), and tephra fell in Cusúa (8 km NW). At 1905 a pyroclastic flow descended the S and SW flanks.

At 0200 on 28 November an explosion ejected incandescent material that fell on all flanks, and generated apyroclastic flow that descended the Achupashal drainage. Starting before 0500 until 0900 an almost constant roar was heard and incandescent blocks traveled 1 km down the flanks, especially towards the W and NW. Threepyroclastic flows were noted on the S flank. Windows vibrated at the Tungurahua Observatory (OVT) in Guadalupe (14 km N). During the day, an ash plume rose 3 km above the crater and drifted in multiple directions. White ashfall was reported in Manzano, Choglontús (SW), Pondoa (8 km N), and Runtún (6 km NNE). In the evening incandescent blocks that were ejected 300 m above the crater rolled 400-500 m down the flanks. On 29 November an explosion detected at 0611 produced a small pyroclastic flow that traveled 500 m. Another pyroclastic flow at 0955 traveled 1 km W. Gas-and-ash plumes rose 4 km above the crater and drifted SE and W. According to a news article, people in high risk areas on the flanks, in communities such as Cusúa, Juive, Palictahua, and Manzano, evacuated voluntarily.

Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG)Agence France-Presse

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DUKONO Halmahera 1.68°N, 127.88°E; summit elev. 1335 m

Based on analyses of satellite imagery, the Darwin VAAC reported that during 27-28 November ash plumes from Dukono rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted 65-110 km NW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

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

Instituto Geográfico Nacional (IGN) reported that during 23-29 November the submarine eruption continued S of El Hierro Island. During this period, the mean amplitude of the tremor showed a slight increase. On 26 November large steaming fragments of lava appeared intermittently floating over the emission center. On 27 November, the emissions were more intense and a few hundred fragments could be observed floating simultaneously, with mean dimensions between 0.5 and 2 m. Some samples of the fragments were collected from a ship near the emission area.

During the period, 121 seismic events were located, most of them offshore to the N of the island at depths of 15-23 km and a maximum magnitude of 3.3. Seven of these events were felt by residents at a maximum intensity value of III using EMS-98 (European Macroseismic Scale). GPS data analyses trended towards stability in the horizontal components, while in the vertical component most of the stations showed subsidence while stations in the NE of the island also trended towards stability.

Source: Instituto Geográfico Nacional (IGN)

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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 18-25 November and indicated that possible ash plumes rose to an altitude of 2.8 km (9,200 ft) a.s.l. during 19-22 November. Satellite imagery showed a thermal anomaly on the volcano during 18, 20, and 24 November. The Aviation Color Coderemained at Orange.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

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

During 23-29 November, 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 freshspatter nearby. Incandescence was visible from the E and W edges of the Pu’u ‘O’o crater floor, and from the 21 September fissure on the SE flank of Pu’u ‘O’o cone. Pahoehoe flows, fed through lava tubes from the fissure, continued to be active about 5.7 km SE of Pu’u ‘O’o based on intermittent views from satellite. Incandescence from a skylight on the lava tube was also observed. Short lava flows issued from the E edge of the crater floor on 23 November and from both the E and W edges of the crater floor on 27 November.

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)

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

KVERT reported moderate seismic activity at Kizimen during 18-25 November and a thermal anomaly that was detected daily in satellite images. A large lava flow on the NE and E flanks continued to effuse, and the crater was occasionally incandescent at night. Video observations showed gas-and-steam activity during 20 and 22-24 November. The Aviation Color Code remained at Orange.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

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

CENAPRED reported that during 22-28 November steam-and-gas emissions rose from Popocatépetl and crater incandescence was observed during most nights and early mornings. Steam-and-gas emissions occasionally contained small amounts of ash on 29 November.

Source: Centro Nacional de Prevencion de Desastres (CENAPRED)

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

Based on seismicity during 23-28 November, 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. Cloud cover prevented web camera views during 24-25 November, but satellite imagery showed a discontinuous ash plume drifting E and reaching the Atlantic Ocean on 24 November, and a fan-shaped ash plume spreading NE to SE on 25 November. Plumes observed with the web camera during 26-27 November rose 2.3-2.5 km above the crater. According to a news article, flights out of Uruguay were disrupted or cancelled on 26 November due to ash plumes. A plume observed in satellite imagery drifted 300 km E on 28 November. The Alert Level remained at Red.

Sources: Servicio Nacional de Geología y Minería (SERNAGEOMIN)Agence France-Presse

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

Based on information from JMA, the Tokyo VAAC reported that during 23 and 25-29 November explosions from Sakura-jima produced plumes that rose to altitudes of 1.8-2.7 km (6,000-9,000 ft) a.s.l. and drifted W, S, E, and NE.

Source: Tokyo Volcanic Ash Advisory Center (VAAC)

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

INSIVUMEH reported that during 24-25 November block avalanches originated from the crater at Santa María’s Santiaguito lava-dome complex as well as from lava flows. Ash plumes rose 500 m above the crater and drifted SW. During 28-29 November explosions generated shock waves and rumbling noises, as well as ash plumes that rose 700 m above the crater and drifted W. Incandescence was observed at night from Caliente dome and avalanches from lava flows descended the S and NE flanks.

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

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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 18-25 November, and satellite imagery showed a daily thermal anomaly over the lava dome. Ground-based observers noted that a viscous lava flow continued to effuse in the crater formed during a 2010 eruption. An ash plume detected in satellite imagery drifted 21 km W on 18 November. Strong fumarolic activity at the lava dome was observed on 18, 21, and 24 November; clouds prevented observations on the other days of the week. The Aviation Color Code remained at Orange.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

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