SI/USGS Weekly Volcanic Activity Report, 6-12 October 2010

The Weekly Volcanic Activity Report for 6-12 October 2010 is compiled by Sally Kuhn Kennert and published by the Global Volcanism Program. Some selected highlights:

• Piton de la Fournaise: continuing high level of activity, with elevated seismicity and summit inflation
• Planchón-Peteroa: plumes rising to altitudes between 3 and 6 km a.s.l.
• Poás: phreatic eruptions throw material tens of metres above the surface of the crater lake

Click on the map for a larger version (1280 x 898 pixels).

The Smithsonian Institution/United States Geological Survey Weekly Volcanic Activity Report for 29 September – 5 October 2010 is now 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: Piton de la Fournaise (Réunion Island), Planchón-Peteroa (Chile), Reventador (Ecuador).

Ongoing activity: Arenal (Costa Rica), Batu Tara (Indonesia), Dukono (Indonesia), Karymsky (Russia), Kilauea (Hawaii, USA), Kliuchevskoi (Russia), Poás (Costa Rica), Sakura-jima (Japan), Sangay (Ecuador), Shiveluch (Russia), Soufrière Hills (Montserrat).

Piton de la Fournaise (Réunion Island). On 11 October, OVPDLF reported a steady increase in the number and magnitude of volcano-tectonic earthquakes from Piton de la Fournaise since 7 October. During 10-11 October the summit area inflated 3-7 cm and an increase in the number of landslides in the crater was detected. The Alert level remained at 1 (“probable or imminent eruption”). [GVP: Piton de la Fournaise]

Planchón-Peteroa (Chile). SERNAGEOMIN reported that during an overflight of Planchón-Peteroa on 30 September scientists observed an ash plume that rose 400 m and drifted E, diffusing over a wide area of Argentina. Parts of the ash plume drifted E and then NE, traveling tens of kilometers with an altitude as high as 6 km (19,700 ft) a.s.l. Also, a diffuse plume drifted S and SE at an altitude of 3 km (10,000 ft) a.s.l. On 1 October an ash plume drifted N and NW as far as Los Queñes, 30 km NW. A sulfur odor was also reported in Los Queñes. Based on analyses of satellite imagery, pilot observations, and SIGMET notices, the Buenos Aires VAAC reported that during 6-12 October ash plumes from Planchón-Peteroa rose to altitudes of 3-6.1 km (10,000-20,000 ft) a.s.l. and drifted in multiple directions. The Alert Level remained at 4, Yellow. [GVP: Planchón-Peteroa]

Reventador (Ecuador). Based on analyses of satellite imagery and information from IG, the Washington VAAC reported that on 6 October a small ash cloud from Reventador drifted NE. IG also reported that a steam plume rose 1 km above the crater on that same day. [GVP: Reventador]

ONGOING ACTIVITY

Arenal (Costa Rica). OVSICORI-UNA reported that during September, activity originating from Arenal’s Crater C was at a low level and consisted of gas emissions, sporadic Strombolian eruptions, and occasional avalanches. Residents to the N observed material ejected from Strombolian explosions descending the N flank. Acid rain and small amounts of ejected pyroclastic material affected the NE, E, and SE flanks. Crater D produced only fumarolic activity. [GVP: Arenal]

Batu Tara (Indonesia). Based on analyses of satellite imagery, the Darwin VAAC reported that on 6 October ash plumes from Batu Tara rose to an altitude of 1.5 km (5,000 ft) a.s.l. and drifted 55 km W. [GVP: Batu Tara]

Dukono (Indonesia). Based on analyses of satellite imagery, the Darwin VAAC reported that during 6-7 October ash plumes from Dukono rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted 75-110 km W. [GVP: Dukono]

Karymsky (Russia). KVERT reported that seismic activity from Karymsky was above background levels during 1-8 October. The elevated seismicity suggested that ash explosions had occurred, and ash plumes rose to altitudes of 3 and 5.1 km (9,800-16,700 ft) a.s.l. on 3 and 4 October, respectively. Thermal anomalies were seen in satellite imagery during 4-5 October, and ash plumes drifted 33 km SE on 7 October. The Aviation Colour Code level remained at Orange. [GVP: Karymsky]

Kilauea (Alaska, USA). During 6-12 October, HVO reported that activity at Kilauea continued from the summit caldera and the east rift zone. At the summit caldera, the level of the lava-pool surface in the deep pit within Halema’uma’u crater remained mostly stable between 150 and 160 m below the crater floor; periodically the lava rose 10-30 m above that level. Glow from the vent was also visible at night. A plume from the vent drifted mainly SW. At the east rift zone, lava that flowed through the TEB lava-tube system mainly fed the Puhi-o-Kalaikini ocean entry. Break-outs of lava from a tube near the end of Highway 130 and NW of Kalapana on 4 October and other small break-outs during 6-12 October were noted. On 7 October another ocean entry point developed on the Puhi-o-Kalaikini delta, just W of the first entry. Lava from a vent on the NW edge of Pu’u ‘O’o crater flowed E across the crater floor during most of the reporting period. On 6 October a vent on the N floor of the crater opened and effused lava that buried the E portion of the crater with lava about 10 m thick. On 8 October, lava drained back into the vent on the N floor. Lava-flow activity on the crater floor was intermittent during 8-10 October. The next day the flows had stalled. [GVP: Kilauea]

Kliuchevskoi (Russia). KVERT reported that during 1-8 October seismic activity from Kliuchevskoi was above background levels and lava from the summit crater flowed down the SW flank. Satellite imagery analyses showed a large and intense daily thermal anomaly over the volcano. Strombolian activity was observed almost every day, and gas-and-ash plumes rose to an altitude of 6.3 km (20,700 ft) a.s.l. Ash plumes seen in satellite imagery drifted 50 km SE during 5-6 October. The Aviation Color Code level remained at Orange. Based on analyses of satellite imagery and information from KVERT, the Tokyo VAAC reported ash drifting NE on 11 October. The next day an eruption seen in satellite imagery produced an ash plume that rose to an altitude of 10.1 km (33,000 ft) a.s.l. and drifted E. A subsequent notice stated that ash had dissipated. The Aviation Colour Code level remained at Orange. [GVP: Kliuchevskoi]

Poás (Costa Rica). OVSICORI-UNA reported that during September several phreatic eruptions from the central part of Laguna Caliente, a summit lake of Poás, ejected material that fell back into the lake. Gas plumes rose a few meters to several tens of meters above the water surface. The temperature of the lava dome was 810 degrees Celsius at accessible areas. [GVP: Poás]

Sakura-jima (Japan). Based on information from JMA, the Tokyo VAAC reported that explosions from Sakura-jima during 7-10 October produced plumes that rose to altitudes of 1.5-2.1 km (6,000-7,000 ft) a.s.l. and drifted NW, NE, SE, and S. On 8 October a pilot reported that an ash plume rose to an altitude of 2.7 km (9,000 ft) a.s.l. [GVP: Sakura-jima]

Sangay (Ecuador). The Washington VAAC reported that on 6 October small ash clouds from Sangay were observed by a pilot. The ash clouds were seen in satellite imagery drifting WNW. [GVP: Sangay]

Shiveluch (Russia). KVERT reported that during 1-8 October seismic activity from Shiveluch was above background levels, suggesting that possible ash plumes rose to an altitude of 6.5 km (21,300 ft) a.s.l. during 5-7 October. Satellite imagery analysis showed a thermal anomaly on the volcano and gas-and-steam plumes that drifted 190 km SE on 2 and 3 October. Gas-and-steam plumes sometimes containing ash were visually observed during 3-7 October. The Aviation Colour Code level remained at Orange. [GVP: Shiveluch]

Soufrière Hills (Montserrat). MVO reported that during 1-8 October activity from the Soufrière Hills lava dome was at a low level. A pyroclastic flow traveled W down Gages Valley and into Spring Ghaut on 2 October. Several lahars flowed down the Belham valley to the NW. According to the Washington VAAC, MVO reported that an ash plume rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted W. The next day an ash plume seen in satellite imagery drifted 55 km WNW and NW. A few hours later an area of ash at an altitude of 2.1 km (7,000 ft) a.s.l. was seen 140 km WNW. On 11 October a diffuse steam-and-gas plume drifted NNW. The Hazard Level remained at 3. [GVP: Soufrière Hills]

The foregoing is a summary of the Smithsonian Institution/United States Geological Survey Weekly Volcanic Activity Report covering 6-12 October 2010. 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.