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SI/USGS Weekly Volcanic Activity Report, 6-12 May 2009 14 May 2009

Posted by admin in activity reports, Africa, Alaska, Arenal, Batu Tara, Chaitén, Chile, Colombia, Congo (Dem. Rep.), Costa Rica, Dukono, Ebeko, Ecuador, eruptions, Galeras, Hawaii, Indonesia, Japan, Kamchatka, Kilauea, Llaima, Nevado del Huila, Nyiragongo, Rabaul, Redoubt, Rinjani, Russia, Sakura-jima, Shiveluch, Suwanose-jima, Tungurahua, United States, Veniaminof, volcanoes, Weekly Volcanic Activity Reports.

SI/USGS Weekly Volcanic Activity Report 6-12 May 2009

The Smithsonian Institution/United States Geological Survey Weekly Volcanic Activity Report covering 6-12 May 2009 is available on the Global Volcanism Program website. The following is a summary and not a substitute for the full report.

New activity: Galeras (Colombia), Nyiragongo (Dem. Rep. of Congo), Rinjani (Lombok Island, Indonesia), Veniaminof (Alaska, USA).

Ongoing activity: Arenal (Costa Rica), Batu Tara (Komba Island, Indonesia), Chaitén (Chile), Dukono (Halmahera, Indonesia), Ebeko (Paramushir Island, Russia), Kilauea (Hawaii, USA), Llaima (Chile), Nevado del Huila (Colombia), Rabaul (Papua New Guinea), Redoubt (Alaska, USA), Sakura-jima (Japan), Shiveluch (Kamchatka, Russia), Suwanose-jima (Japan), Tungurahua (Ecuador).


Galeras (Colombia). Gas-and-ash plumes rose to 5.8 km and drifted NE on 6 May. A 90-100 m diameter vent in the main crater was observed producing incandescence during an overflight, and white plumes originated from multiple points inside and outside the crater. There was little volcanic tremor. On 9 May there was a magnitude 2.2 volcano-tectonic earthquake 6 km to the NE of the main crater at a depth of 10 km; seismicity (consisting of hybrid earthquakes and tremor) increased on 11 May, and hybrid earthquakes and tremor were detected. On 12 May steam plumes rose 250 m and drifted NW. The increase in seismicity, with other factors, is interpreted by INGEOMINAS as indicating a possible eruption in the offing, and the alert level for Galeras was raised on 11 May.

Nyiragongo (Dem. Rep. of Congo). Incandescence from Nyiragongo, ‘volcanic dust’ in the air and increased temperatures around the volcano have been reported by news outlets and the Goma Volcano Observatory.

Rinjani (Lombok Island, Indonesia). Seismicity continued to be elevated over 3-7 May, with tremor present, and on 4 May there was an ash eruption from Barujari cone producing a white-to-brown plume that rose 500-700 m and drifted N. Thick white ‘smoke’ was seen on 7 May.

Veniaminof (Alaska). Seismic activity at Veniaminof increased over 6-7 May, with low magnitude earthquakes occurring at rates of 5-10 per hour during quieter periods and 1-3 per minute during periods of more intense activity. Seismicity remained elevated over 8-12 May. The summit caldera cone was seen to be steaming in its usual manner.


Arenal (Costa Rica). Activity during April originated mainly from Crater C: gas emissions, sporadic Strombolian
eruptions, avalanches descending S, SW, and N flanks, small amounts of ejected pyroclastic material and acid rain affecting NE and SE flanks. Crater D showed only fumarolic activity.

Batu Tara (Komba Island, Indonesia). On 5 May an ash plume rose to 2.4 km a.s.l. and drifted 55 km W.

Chaitén (Chile). The dome complex continued to grow and produced 2 km gas-and-ash plumes and collapse-generated block-and-ash flows during 29 April-4 May. The large central spine was found during an overflight on 1 May to have fractured into three main blocks, and the surface of the lava dome complex was very irregular with several spines that had grown to heights of 100 m. During 5 and 10-12 May, ash plumes rose to 2.1-4.6 km a.s.l. and drifted N, NE, and ENE.

Dukono (Halmahera, Indonesia). Ash plumes from rose to 3-3.7 km a.s.l. and drifted 20-110 km SE over 5-7 May.

Ebeko (Paramushir Island, Russia). Activity continued with gas-and-steam plumes containing small amounts of ash observed on 2 May. Ash plumes rose to 2.1-2.4 km a.s.l. and drifted SW and SE over 9-11 May.

Kilauea (Hawaii, USA). Lava continued to flow through the lava tube system to the ocean entries at Waikupanaha (where there were explosions on 10 May) and Kupapa’u (where a bench collapse was detected through seismic signals on 6 May). A small active surface flow was observed. The Halema’uma’u crater vent continued to produce a white plume
that that drifted W and SW, and the brightest incandescence seen since early December 2008 was produced by a molten lava pool deep below the floor of the crater. Sulphur dioxide emissions were elevated, at 1100 tonnes/day (8 May) and 700 tonnes/day (10 May). The 2003-2007 average rate was 140 tonnes/day

Llaima (Chile). Sporadic incandescence was reported from an area in the SW part of the main crater over 28 April to 11 May, corresponding to a small outcrop of lava which produced occasional blocks which rolled down the W flank. Tephra was ejected from an area on the E flank which showed incandescence during the night and an almost continuous orange-brown plume rose 200 m during 5-11 May.

Nevado del Huila (Colombia). Extrusion of juvenile material was detected at the lava dome during overflights on 7 and 9 May.

Rabaul (Papua New Guinea). Ash plumes from Tavurvur cone rose to 3 km a.s.l. and drifted about 35 km E on 9 May.

Redoubt (Alaska, USA). Lava dome growth continues at Redoubt. Seismicity was elevated over 6-12 May and occasional rockfalls and steam-and-gas emissions (possibly with some ash) were observed. Seismicity intensified during 5-6 May, with nearly continuous small earthquakes near the summit, and steam emissions were vigorous, with minor ash content. Tremor nearly doubled in intensity on 6 May and the number of events increased; an ash emission produced a plume that rose to 3.7 km a.s.l. Over 6-7 May seismicity declined but continuous small earthquakes continued at the summit area. On 12 May seismicity decreased to low levels compared to other phases of
the eruption.

Sakura-jima (Japan). Plumes on 9 May rose to 2.1-3 km a.s.l. and drifted S, and on 12 May an ash plume drifted E at 1.8 km a.s.l.

Shiveluch (Kamchatka, Russia). Over 1-8 May seismic activity was above background levels, plumes probably rose to 6.7 km a.s.l., and a daily thermal anomaly at the lava dome was detected.

Suwanose-jima (Japan). Explosions were reported over 7-9 and 12 May.

Tungurahua (Ecuador). Ashfall occurred in Baños, about 8 km N, on 6 May. Steam plumes rose to below 6.5 km a.s.l. and drifted W over 6-8 May. The volcano was very noisy over 9-11 May, with cannonades and roaring sounds being reported. An ash plume rose to 6 km a.s.l. on 9 May, and ash plumes rose to 8 km a.s.l. on 10 May.


The foregoing is a summary of the Smithsonian Institution/United States Geological Survey Weekly Volcanic Activity Report covering 6-12 May 2009. It is provided for information only, and is based on but not a substitute for the full report, which comes with its own criteria and disclaimers. The map base is derived from the Smithsonian Institution/USGS/US Naval Research Laboratory This Dynamic Planet website.

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