SI/USGS Weekly Volcanic Activity Report 9-15 September 2009

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The Smithsonian Institution/United States Geological Survey Weekly Volcanic Activity Report for 9-15 September 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/unrest: Langila (Papua New Guinea), Mayon (Philippines), Shiveluch (Russia).

Ongoing activity: Bagana (Papua New Guinea), Barren Island (India), Batu Tara (Indonesia), Chaitén (Chile), Dukono (Indonesia), Fuego (Guatemala), Kilauea (Hawaii, USA), Pacaya (Guatemala), Popocatépetl (Mexico), Rabaul (Papua New Guinea), Sakura-jima (Japan), Santa María (Guatemala), Slamet (Indonesia), Suwanose-jima (Japan).

Note: a.s.l. = ‘above sea level’.

NEW ACTIVITY

Langila (Papua New Guinea). An ash plume rose to 3 km a.s.l. and drifted 35 km W on 12 September.

Mayon (Philippines). During 14-15 September 11 earthquakes were detected, steam plumes drifted NW and ENE, and faint incandescence was observed at night. Sulphur dioxide gas output decreased. On 15 September three ash explosions produced a brownish plume that rose no higher than 700 m above the crater and drifted SW.

Schiveluch (Russia). During 4-11 September seismic activity was above background levels. A large daily thermal anomaly over the lava dome was detected on satellite imagery. Interpretations of seismic data suggested that ash plumes rose to 4.2 km a.s.l. and hot avalanches occurred at the lava dome. During 4-9 September gas-and-steam plumes rose to 4 km a.s.l. An ash plume drifted 80 km E on 8 September. On 11 September strong explosions were reported, and seismic data suggested that ash plumes rose to above 15 km a.s.l. Pyroclastic flow activity from the lava dome lasting eight minutes was detected by the seismic network, with resulting plumes rising to approximately 10 km a.s.l. Ten more events characterized as ash explosions and either pyroclastic flows or avalanches were detected. During 11-12 September seismicity decreased, and seismic data indicated that ash plumes rose to 4.5-6.5 km a.s.l.

ONGOING ACTIVITY

Bagana (Papua New Guinea). During 12-13 September ash plumes rose to 2.4 km a.s.l. and drifted 35-65 km NW and W.

Barren Island (India). During 13-14 September ash plumes rose to 2.4 km a.s.l. and drifted about 20-100 km W and NE.

Batu Tara (Indonesia). During 9-11 and 14-15 September ash plumes rose to 1.5 km a.s.l. and drifted 25-45 km W and NW.

Chaitén (Chile). A diffuse ash plume from the lava-dome complex, possibly mixed with steam and gas, rose to 2.1 km a.s.l. and drifted NE and SE on 15 September.

Dukono (Indonesia). On 12 and 14 September ash plumes rose to 2.4 km a.s.l. and drifted 25-75 km W and SW.

Fuego (Guatemala). Explosions produced ash plumes that rose to 4.1-4.7 km a.s.l. and drifted up to 10 km W, SW, and S on 10 and 14 September. Some explosions were accompanied by rumbling noises and shock waves. Incandescent material was ejected 100 m high and avalanches descended multiple ravines.

Kilauea (Hawaii, USA). Lava continued to flow SE through the lava tube system during 9-15 September to the Waikupanaha ocean entry, where weak sporadic explosions were seen on 10 September. Thermal anomalies and visual observations revealed active surface flows. The Halema’uma’u vent continued to produce a diffuse white plume that drifted mainly SW; a rockfall caused the plume to turn brown on 9 September. Incandescence of variable intensity from small opening in the floor of the vent was visible at night. The sulfur dioxide emission rate at the summit remained elevated: 900 tonnes/day was measured on 11 September (2003-2007 average rate = 140 tonnes/day).

Pacaya (Guatemala). White and blue plumes from MacKenney cone rose 300 m and drifted NW, S and SW and multiple lava flows 75-250 m long travelled W on 11 and 14 September.

Popocatépetl (Mexico). During 10-14 September emissions of steam and gas contained slight amounts of ash.

Rabaul (Papua New Guinea). Grey ash and white plumes from Tavurvur cone rose 1.5 km during 4-10 September, and ashfall was reported in Rabaul town and surrounding areas. Incandescence from the summit crater was occasionally visible at night, incandescent lava fragments were ejected and rumbling and roaring noises reported. ‘Several large explosions occurred during an eight-hour period one unspecified evening’. During 11-13 and 15 September ash plumes rose to 2.4 km a.s.l. and drifted 35-130 km N and NW.

Sakura-jima (Japan). Explosions produced plumes to 1.5-2.7 km a.s.l. which drifted S, SE and E.

Santa María (Guatemala). An explosion from Santiaguito lava dome complex on 14 September produced an ash plume that rose to 3.3 km a.s.l. which drifted SW and caused ashfall. Avalanches descended the SW flank of the dome.

Slamet (Indonesia). On 12 September a low-level ash plume was reported by a passing pilot.

Suwanose-jima (Japan). Explosions were reported during 13-14 September, with no details of possible resulting ash plumes.

ACKNOWLEDGEMENTS AND DISCLAIMER

The foregoing is a summary of the Smithsonian Institution/United States Geological Survey Weekly Volcanic Activity Report covering 9-15 September 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.

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