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SI/USGS Weekly Volcanic Activity Report 25-31 August 2010 1 September 2010

Posted by admin in activity reports, Alaska, Batu Tara, Caribbean, Cleveland, Colombia, Dukono, Ecuador, Ekarma, eruptions, Galeras, Hawaii, Indonesia, Japan, Kamchatka, Karymsky, Kilauea, Kliuchevskoi, Manam, Nevado del Huila, Papua New Guinea, Reventador, Russia, Sakura-jima, Sangay, Shiveluch, Sinabung, Soufrière Hills, Suwanose-jima, United States, Weekly Volcanic Activity Reports.
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Some highlights from a very full week of volcanic activity as reported by the Global Volcanism Program (report compiled by Sally Kuhn Sennert):

  • Ekarma: a steam plume and evidence of a possible recent small eruption reported from this volcano in the Kuril Islands
  • Galeras: an eruption on 25 August, and ashfall up to 30 km from the vent
  • Sinabung: two significant eruptions cause the evacuation of 20,000 to 30,000 local residents
  • Nevado del Huila: ash emissions accompanied by tremor

SI/USGS Weekly Volcanic Activity Report 25-31 August 2010

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

The Smithsonian Institution/United States Geological Survey Weekly Volcanic Activity Report for 25-31 August 2010 is now available on the Global Volcanism Program website. The following is a summary and not a substitute for the full report.

New activity/unrest: Ekarma (Russia), Galeras (Colombia), Manam (Papua New Guinea), Sinabung (Indonesia).

Ongoing activity: Batu Tara (Indonesia), Cleveland (Alaska, USA), Dukono (Indonesia), Karymsky (Russia), Kilauea (Hawaii USA), Kliuchevskoi (Russia), Nevado del Huila (Colombia), Reventador (Ecuador), Sakura-jima (Japan), Sangay (Ecuador), Shiveluch (Russia), Soufrière Hills (Montserrat), Suwanose-jima (Japan).

Note: a.s.l. = ‘above sea level’.

NEW ACTIVITY/UNREST

Ekarma (Russia). SVERT reported that on 10 August scientists observed a vigorous steam plume from Ekarma that rose to an altitude of 1.8 km (5,900 ft) a.s.l. while visiting Sarychev Peak, 110 km SSW. On 24 August scientists visited Ekarma Island and observed continuous vigorous gas emissions from a new vent located on the S flank, about 250 m below the summit. The flanks had been blanketed by a layer of fine ash with a thickness exceeding 5 cm in the vicinity of the vent. Two recent lahar deposits were seen on the S flank. Based on their observations, SVERT speculated that a small eruption may have occurred between early June and late July 2010. Ekarma does not have a seismic network; satellite image analysis and infrequent ground observations are the primary tool for monitoring many of the Kuril Islands volcanoes. [GVP: Ekarma]

Galeras (Colombia). An eruption from Galeras that began at 0400 on 25 August prompted INGEOMINAS to raise the Alert Level to I (Red; “imminent eruption or in progress”). Meteorological cloud cover initially prevented visual observations of the summit. Seismicity associated with the eruption continued for a period of about 12 hours and gradually declined in the afternoon. The Alert Level was lowered to II (Orange; “probable eruption in term of days or weeks”). Scientists aboard an overflight later that day observed ash-and-gas emissions from multiple areas of the active cone, and thermal anomalies that were detected on the N side of the cone. Ash fell to the NW, as far away as 30 km. According to news articles, about 7,000 were requested by officials to evacuate, although few left their homes. During 26-31 August at least 12 earthquakes, M 2-4, were located within a 2-km radius from the crater, at depths not more than 3 km. Gas plumes drifted NW, then S. [GVP: Galeras]

Manam (Papua New Guinea). RVO reported that during 13-26 August incandescence from Manam’s South Crater was visible at night. Main Crater emitted diffuse white vapour. During 27-28 August incandescence emanated from both craters and brightened every 15-20 minutes. At that time, incandescent lava fragments ejected tens to hundreds of meters above South Crater were reported from observers in Bogia, about 23 km SSW. Weak explosions were heard at 15-20 minute intervals. During 28-29 August diffuse white-to-blue vapour emissions from Main Crater were occasionally accompanied by diffuse grey ash plumes. Incandescent lava fragments continued to be ejected. Based on analysis of satellite imagery, the Darwin VAAC reported that on 30 August an ash plume rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted 55 km NW. [GVP: Manam]

Sinabung (Indonesia). CVGHM reported that on 28 August Sinabung emitted diffuse white plumes that rose 20 m and showed no signs of increased activity. On 29 August rumbling was heard, prompting authorizes to contact and move people living within a 6-km-radius of the volcano. Later that day, an explosion produced an ash plume that rose 1.5 km above the crater, and the Alert Level was raised to 4 (on a scale of 1-4). Media footage of the eruption at one point showed two closely spaced ash plumes from vents near the summit, causing domestic flights to be diverted. The next day a second, more powerful, explosion generated an ash plume that rose 2 km above the crater. The number of people media sources reported had evacuated ranged from 20,000-30,000. Ash fell in nearby areas and a strong sulphur odor was reported. Nighttime video showed incandescent material descending the flank of the volcano. [GVP: Sinabung]

ONGOING ACTIVITY

Batu Tara (Indonesia). Based on analyses of satellite imagery, the Darwin VAAC reported that during 26-28 August ash plumes from Batu Tara rose to an altitude of 1.5 km (5,000 ft) a.s.l. and drifted 55-75 km. The plumes drifted W and NW during 27-28 August. [GVP: Batu Tara]

Cleveland (Alaska, USA). AVO reported that on 26 August the Volcano Alert Level for Cleveland was raised to Advisory, and the Aviation Colour Code was raised to Yellow, due to a persistent thermal anomaly near the summit visible in satellite imagery on most days during 16-24 August. Cloudy weather conditions prevented views of the summit during 25-29 August. A thermal anomaly was again seen in satellite imagery at night during 29-30 August. No current seismic information was available because Cleveland does not have a real-time seismic network. [GVP: Cleveland]

Dukono (Indonesia). Based on analyses of satellite imagery, the Darwin VAAC reported that during 25-29 August ash plumes from Dukono rose to altitudes of 2.1-3 km (7,000-10,000 ft) a.s.l. and drifted 35-110 km W and NE. [GVP: Dukono]

Karymsky (Russia). KVERT reported that during 20-27 August seismic activity from Karymsky was above background levels and suggested that possible ash plumes rose to an altitude of 3.8 km (12,500 ft) a.s.l. Satellite imagery showed a thermal anomaly over the volcano during 20 and 23-24 August. The Aviation Colour Code level remained at Orange. [GVP: Karymsky]

Kilauea (Hawaii, USA). During 25-31 August 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 the floor of Halema’uma’u crater remained mostly stable; glow from the vent was also visible at night. A plume from the vent drifted SW. At Pu’u ‘O’o crater, incandescence emanated from an active hornito on the N floor. At the east rift zone, lava that flowed through the TEB lava-tube system fed minor surface flows on the coastal plain, as well as two ocean entries at Puhi-o-Kalaikini, SW of Kalapana. [GVP: Kilauea]

Kliuchevskoi (Russia). KVERT reported that 20-27 August seismic activity from Kliuchevskoi was above background levels and lava flowed down the SW flank. Strombolian activity and gas-and-ash emissions were observed on 20 and 21 August. Cloud cover prevented observations the other days. Satellite imagery analyses showed a large and intense daily thermal anomaly from the volcano and ash plumes that drifted more than 200 km SE on 20 August. Based on analyses of satellite imagery and information from KEMSD, the Tokyo VAAC reported that an eruption on 28 August produced plumes that rose to altitudes of 7.6-10.4 km (25,000-34,000 ft) a.s.l. and drifted SE. Satellite imagery showed a possible eruption on 30 August. The Aviation Colour Code level remained at Orange. [GVP: Kliuchevskoi]

Nevado del Huila (Colombia). According to the Washington VAAC, the Popayán Volcano Observatory (INGEOMINAS) received several reports from towns W of Nevado del Huila that indicated ash emissions on 30 August. Ash was not seen in satellite imagery, although extensive clouds were present in the area. A thermal anomaly was detected, however. INGEOMINAS reported that a pulse of tremor was detected, associated with an ash emission seen in the web camera at Tafxnú. Ashfall was later confirmed in Toribio, 27 km W. [GVP: Nevado del Huila]

Reventador (Ecuador). The Washington VAAC reported that on 30 August an ash plume was observed near Reventador by a pilot. Ash was not seen in satellite imagery. [GVP: Reventador]

Sakura-jima (Japan). Based on information from JMA, the Tokyo VAAC reported that explosions from Sakura-jima during 26-31 August produced plumes that rose to altitudes of 1.2-2.1 km (4,000-7,000 ft) a.s.l. Some of the plumes drifted N and NW. [GVP: Sakura-jima]

Sangay (Ecuador). The Washington VAAC reported that on 30 August an ash plume was observed near Sangay by a pilot. Ash was not seen in satellite imagery. [GVP: Sangay]

Shiveluch (Russia). KVERT reported that during 20-27 August seismic activity from Shiveluch was above background levels, suggesting that possible ash plumes rose to an altitude of 8.5 km (27,900 ft) a.s.l. during 20-24 August. Gas-and-ash plumes were observed on 20 and 21 August. Satellite imagery analysis showed a thermal anomaly on the volcano during 20-22 and 24 August. The Aviation Colour Code level remained at Orange. [GVP: Shiveluch]

Soufrière Hills (Montserrat). MVO reported that most of the rockfalls and pyroclastic flows detected during 20-27 August originated from a vertical face on the SE side of the lava dome and traveled W down Gages valley and E down the Tar River valley. The pyroclastic flows traveled no longer than 1.5 km and produced weakly convecting ash clouds that rose a few hundred metres. The Hazard Level remained at 3. [GVP: Soufrière Hills]

Suwanose-jima (Japan). Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima on 25 and 27 August. Details of possible resulting plumes were not reported. [GVP: Suwanose-jima]

The foregoing is a summary of the Smithsonian Institution/United States Geological Survey Weekly Volcanic Activity Report covering 25-31 August 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.

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