SI/USGS Weekly Volcanic Activity Report 1-7 September 2010

Another week, another Weekly Volcanic Activity Report from the volcano-watchers of the Global Volcanism Program. The report is compiled by Sally Kuhn Sennert.

• Ekarma: continuing strong steam-and-gas emissions
• Etna: a powerful explosion followed by ash emissions on 25 August
• Planchón-Peteroa: an explosive eruption on 6 September
• Kliuchevskoi: a possible eruption on 3 September

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

The Smithsonian Institution/United States Geological Survey Weekly Volcanic Activity Report for 1-7 September 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: Ekarma (Russia), Etna (Italy), Kliuchevskoi (Russia), Manam (Papua New Guinea), Planchón-Peteroa (Chile), Seulawah Agam (Indonesia), Sinabung (Indonesia), Villarrica (Chile).

Ongoing activity: Batu Tara (Indonesia), Bezymianny (Russia), Cleveland (Alaska, USA), Dukono (Indonesia), Karymsky (Russia), Kilauea (Hawaii USA), Pacaya (Guatemala), Sakura-jima (Japan), Sangay (Ecuador), Santa María (Guatemala), Shiveluch (Russia).

Note: a.s.l. = ‘above sea level’.

NEW ACTIVITY/UNREST

Ekarma (Russia). On 6 September, SVERT reported that strong steam-and-gas activity from Ekarma continued. 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]

Etna (Italy). INGV-CT reported that on 25 August a powerful explosion from Etna’s Bocca Nuova crater initiated a series of ash  emissions, which continued at decreasing strength for about 20 minutes. A thermal camera located at La Montagnola, 3 km S of the summit craters, showed ejected hot material and a cauliflower-shaped, dark grey ash plume that rose about 1 km and drifted E. Ashfall was reported in areas SE from Etna to Catania (27 km S). An inspection the next morning revealed that the W wall of the BN-1 crater of Bocca Nuova had collapsed. During 25-29 August a total of seven explosions were recorded. [GVP: Etna]

Kliuchevskoi (Russia). KVERT reported that 27 August-3 September seismic activity from Kliuchevskoi was above background levels and lava  flowed down the SW flank. Satellite imagery analyses showed a large and intense daily thermal anomaly over the volcano. On 27 August, activity increased; ash plumes rose to an altitude of 6 km (19,700 ft) a.s.l. and drifted 120 km SE. Strombolian  activity was observed during 27-30 August. Phreatic explosions occurred on the SW flank on 29 and 30 August. Ash plumes rose to an altitude of 6.5 km (21,300 ft) a.s.l. on 30 August and drifted 278 km SE. Based on analyses of satellite imagery and information from the Yelizovo Airport (UHPP), the Tokyo VAAC reported a possible eruption on 3 September. Subsequent images showed continuing emissions. Later that day a notice stated that ash had dissipated. Another possible eruption that day produced a plume that rose to an altitude of 5.5 km (18,000 ft) a.s.l. and drifted E. During 4-7 September eruptions reported by KVERT and seen in satellite imagery produced ash plumes that rose to altitudes of 5.2-7 km (17,000-23,000 ft) a.s.l. and drifted NW, E, and SE. The Aviation Colour Code level remained at Orange. [GVP: Kliuchevskoi]

Manam (Papua New Guinea). RVO reported that ash  plumes and diffuse blue vapor plumes rose 150 m from Manam’s Main Crater on 30 August. That same day grey emissions rose from South Crater at 5-10 minute intervals. During 30 August-2 September incandescence was observed when the craters could be seen. [GVP: Manam]

Planchón-Peteroa (Chile). SERNAGEOMIN reported that on 6 September an explosive eruption from Planchón-Peteroa produced an ash  plume that rose 1.2 km above the complex and drifted mainly E to a distance of 30 km, with some parts of the plume going N and S. That same day SERNAGEOMIN received pictures from Romeral (approximately 61 km NW) that showed ash-and-gas plumes rising 200 m. [GVP: Planchón-Peteroa]

Seulawah Agam (Indonesia). CVGHM  reported that although seismicity from Seulawah Agam fluctuated during April to August 2010, the data reflected increased activity overall. On 1 September, CVGHM raised the Alert Level to 2 (on a scale of 1-4) and restricted visitors from approaching the crater within a 3-km radius. [GVP: Seulawah Agam]

Sinabung (Indonesia). According to news articles, about 6,000 of the approximately 30,000 people that evacuated the area around Sinabung after the eruption during 29-30 August returned home within a few days because activity had decreased. The Darwin VAAC reported a large explosion on 3 September, based on information from CVGHM. News reports stated that the explosion vibrated homes and trees on the flanks, and generated a 3-km-high ash  plume. CVGHM reported that another large explosion on 7 September produced an ash plume that rose 5 km above the crater and drifted SE. Strong vibrations caused by the explosion were detected as far away as 8 km SE. [GVP: Sinabung]

Villarrica (Chile). Based on analyses of satellite imagery, the Buenos Aires VAAC reported that on 4 September a diffuse ash plume from Villarrica, possibly containing steam and gas, drifted NE. [GVP: Villarrica]

ONGOING ACTIVITY

Batu-Tara (Indonesia). Based on analyses of satellite imagery, the Darwin VAAC reported that during 1-7 September ash plumes from Batu Tara rose to altitudes of 1.5-2.4 km (5,000-8,000 ft) a.s.l. and drifted 45-65 km W and NW. [GVP: Batu Tara]

Bezymianny (Russia). KVERT reported that a thermal anomaly over Bezymianny was observed in satellite imagery on 29 August and 1 September. Gas-and-steam activity was also noted on 1 September. Cloud cover prevented observations of the volcano on the other days during 27 August-3 September. The Aviation Colour Code level remained at Yellow. [GVP: Bezymianny]

Cleveland (Alaska, USA). AVO reported that during 31 August-1 September thermal anomalies from Cleveland were detected in satellite imagery. The Volcano Alert Level remained at Advisory and the Aviation Colour Code remained at Yellow. 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 1-2 and 6-7 September ash plumes from Dukono rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted almost 95 km W and NW. [GVP: Dukono]

Karymsky (Russia). KVERT  reported that during 27 August-3 September seismic activity from Karymsky was above background levels and suggested that possible ash plumes rose to an altitude of 3.7 km (12,100 ft) a.s.l.  Satellite imagery showed a thermal anomaly over the volcano during the week and an ash plume that drifted 23 km on 28 August. The Aviation Colour Code level remained at Orange. [GVP: Karymsky]

Kilauea (Hawaii, USA). During 1-7 September 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 and deposited ash nearby. At Pu’u ‘O’o crater, incandescence emanated from an active hornito on the N floor. On 4 September lava  started to flow along the S margin of the crater floor and was active the next day. 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 the Puhi-o-Kalaikini ocean entry. [GVP: Kilauea]

Pacaya (Guatemala). INSIVUMEH reported that during 1-2 September steam plumes rose from Pacaya’s MacKenney cone and drifted NE and W. [GVP: Pacaya]

Sakura-jima (Japan). Based on information from JMA, the Tokyo VAAC  reported that explosions from Sakura-jima during 1-5 September produced plumes that rose to altitudes of 1.5-2.4 km (5,000-8,000 ft) a.s.l. Some of the plumes drifted N, NW, and W. During 2-4 September pilots reported that ash plumes rose to altitudes of 2.1-3.4 km (7,000-11,000 ft) a.s.l. An explosion also occurred on 7 September. [GVP: Sakura-jima]

Sangay (Ecuador). The Washington VAAC reported that on 5 September an ash plume from Sangay that rose to an altitude of 5.5 km (18,000 ft) a.s.l. was observed by a pilot. Ash was not seen in satellite imagery. [GVP: Sangay]

Santa María (Guatemala). INSIVUMEH reported that on 1 September fumarolic plumes from Santa María’s Santiaguito lava dome complex rose less than 100 m above the crater and drifted SE. Ashfall was reported in an area to the SW. On 2 September block avalanches descended the W flank. On 2 and 6 September explosions produced ash plumes that rose 500-1,000 m and drifted W and SW. [GVP: Santa María]

Shiveluch (Russia). KVERT  reported that during 27 August-3 September 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.  Satellite imagery analysis showed a thermal anomaly on the volcano. Gas-and-ash plumes were observed during 27-30 August. Based on information from KEMSD and satellite imagery analyses, the Tokyo VAAC reported that during 2-3 September eruptions produced plumes that rose to an altitude of 6.7 km (22,000 ft) a.s.l. The Aviation Colour Code level remained at Orange. [GVP: Shiveluch]

The foregoing is a summary of the Smithsonian Institution/United States Geological Survey Weekly Volcanic Activity Report covering 1-7 September 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.