The Smithsonian Institution/United States Geological Survey Weekly Volcanic Activity Report covering 27 May-2 June 2009 is available on the Global Volcanism Program website. The following is a summary and not a substitute for the full report.

• The current report: Weekly Volcanic Activity Report.
• Previous reports: Weekly Reports Archive.
• The SI/USGS map of volcanoes discussed this week.

New activity: Karangetang (Indonesia), Makian (Indonesia), Slamet (Indonesia).

Ongoing activity: Bagana (Papua New Guinea), Batu Tara (Indonesia), Chaitén (Chile), Dukono (Indonesia), Etna (Italy), Kilauea (Hawaii, USA), Llaima (Chile), Nevado del Huila (Colombia), Popocatépetl (Mexico), Rabaul (Papua New Guinea), Redoubt (Alaska, USA), Sakura-jima (Japan), Shiveluch (Russia), Soufrière Hills (Montserrat), Tungurahua (Ecuador), Ubinas (Peru).

NEW ACTIVITY

Karangetang (Indonesia). 30-31 May, seismicity increased and tremor was detected. Diffuse white plumes rose 10-50 m and crater incandescence was seen on 30 May, white emissions rose 100 m above Utama Crater on 31 May, incandescent material descended as far as 2.3 m, mostly down S flank.

Makian (Indonesia). Seismicity, particularly tremor, increased during 28 May-2 June.

Slamet (Indonesia). 27 May, ash plume rose to 4.3 km a.s.l., possible plume rose to 6.1 km.

ONGOING ACTIVITY

Bagana (Papua New Guinea). 2 June, ash plume to 2.4 km a.s.l., drifted 75 km W.

Batu Tara (Indonesia). 27 May-2 June, ash plumes to 2.4 km a.s.l., drifted 25-75 km NW, W and SW; thermal anomaly detected 29 May.

Chaitén (Chile). 20-27 May, gas-and-ash plumes rose 1.5 km from the growing lava dome complex and collapses caused by instable slopes generated block-and-ash flows. Seismicity remained elevated with large hybrid earthquakes at 5-9 km beneath the western part of the dome complex. 28-29 May and 1-2 June, ash plumes rose to 1.8-2.4 km a.s.l.

Dukono (Indonesia). 27-28 May, ash plumes to 3 km a.s.l., drifted 55-110 km NE.

Etna (Italy). 25-31 May, the NW-SE-trending fissure E of the summit craters continued to produce active lava flows, There was degassing from the Northeast Crater, the NW and SE Bocca Nuova vents, from the E flank of the Southeast Crater and at summit fumarolic fields.

Kilauea (Hawaii, USA). 27 May-2 June, lava continued to flow SE through lava tubes to the Waikupanaha ocean entry and (until 31 May) the Kupapa’u ocean entry. Active surface lava flows were also detected on 30 May. The Halema’uma’u crater vent continued to produce a mainly white plume with an occasional brown tinge, that drifted mainly SW. A molten lava pool near the base of the cavity produced varying incandescence.

Llaima (Chile). A 2-square-kilometre area of elevated temperatures was observed on the E flank during an overflight on 1 June. Small areas of gas emission, a small cone in formation about 800 m below the crater and a 300-metre-long E-W-trending fissure 200 m from the rim of the main crater, emitting brown ash and steam plumes, were also observed. There were weak fumaroles at the summit crater.

Nevado del Huila (Colombia). A seismic swarm took place on 28 May that included magnitude 4 and 4.8 earthquakes. On 31 May an episode of tremor occurred associated with an ash emission, and a further pulse of tremor was detected on 2 June.

Popocatépetl (Mexico). 27 May-2 June, emissions of steam and gas observed, with slight amounts of ash during 27-29 May.

Rabaul (Papua New Guinea). 21-28 May, white and occasionally blue plumes from Tavurvur cone rose 1 km above the crater and incandescence from the summit crater was observed at night.

Redoubt (Alaska, USA). Seismicity remained low but above background 27 May-2 June. Lava dome growth continued.

Sakura-jima (Japan). An explosion on 30 May produced a plume to 4.6 km a.s.l. that drifted SE. On 31 May an ash plume rose to 3 km a.s.l., and on 1 June eruptions produced plumes to 2.1-3.4 km a.s.l, some of which drifted S.

Shiveluch (Russia). Seismic activity was above background levels 22-29 May; steam-and-gas emissions were observed 21-23 May, and plumes with small amounts of ash rose to 4 km a.s.l. on 22 May. A daily thermal anomaly was detected over the lava dome.

Soufrière Hills (Montserrat). Activity during 22-29 May was at a low level: a possible small explosion followed by a rockfall occurred on 23 May, and a small pyroclastic flow descended 1 km E on 24 May, producing an ash plume that drifted W.

Tungurahua (Ecuador). Strombolian activity was observed at night during 26-28 May, followed by nocturnal incandescence at the crater until 1 June. On 27-29 and 31 May thermal anomalies were detected. There was the usual range of noises: explosions, cannonades and roars. Steam-and-ash plumes rose to 7 km a.s.l. and drifted W and SW on 28 May, and ashfall was reported 28-30 May.

Ubinas (Peru). On 29 and 31 May eruptions produced ash plumes to 5.5-6.7 km a.s.l. that drifted NE and SW. A bluish gas plume with some ash content was reported on 1 June, and gas-and-ash plumes rose 0.9-1.5 km a.s.l. and drifted SE following an explosion on 2 June.

ACKNOWLEDGEMENTS AND DISCLAIMER

The foregoing is a summary of the Smithsonian Institution/United States Geological Survey Weekly Volcanic Activity Report covering 27 May-2 June 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. 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.

For all our coverage of the SI/USGS Weekly Volcanic Activity Reports: Weekly Volcanic Activity Reports « The Volcanism Blog.