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Smithsonian/USGS Weekly Volcanic Activity Report 25-31 May 2011 2 June 2011

Posted by admin in activity reports, Aso, Batu Tara, Costa Rica, Dieng Volcanic Complex, Ecuador, Grímsvötn, Hawaii, Iceland, Indonesia, Japan, Kamchatka, Karymsky, Kilauea, Kizimen, Kliuchevskoi, Mexico, Papua New Guinea, Poás, Popocatépetl, Russia, Sakura-jima, Shiveluch, Taal, Tungurahua, Ulawun, United States, Weekly Volcanic Activity Reports.

The Smithsonian Institution and United States Geological Survey Weekly Volcanic Activity Report has been issued for the week 25-31 May 2011. The report is compiled by Sally Kuhn Sennert. Notable volcanic events this week include:

  • Dieng Volcanic Complex: evacuations following increase in gas emissions and seismic activity
  • Grímsvötn: an eruption characterized by explosive activity and ash plumes, with limited ashfall
  • Kilauea: the level of the Pu’u’O’o lava lake continued to fluctuate
  • Taal: water temperature, acidity and water level all rose in Taal’s Main Crater Lake, and there was an increase in seismic activity

SI/USGS Weekly Volcanic Activity Report 25-31 May 2011

Click on the map for a larger version (1211 x 784 pixels).

The Smithsonian Institution/United States Geological Survey Weekly Volcanic Activity Report for 25-31 May 2011 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: Aso (Japan), Dieng Volcanic Complex (Indonesia), Grímsvötn (Iceland), Kliuchevskoi (Russia), Ulawan (Papua New Guinea).

Ongoing activity: Batu Tara (Indonesia), Karymsky (Russia), Kilauea (Hawaii, USA), Kizimen (Russia), Popocatépetl (Mexico), Poás (Costa Rica), Sakura-jima (Japan), Shiveluch (Russia), Taal (Philippines), Tungurahua (Ecuador).

Note: ‘a.s.l.’ = ‘above sea level’.


Aso (Japan). Based on notices from JMA, the Tokyo VAAC reported that during 25, 27-28 and 31 May ash plumes from Aso rose to altitudes of 1.5-1.8 km (5,000-6,000 ft) a.s.l. and drifted NW, N, E and S. [GVP: Aso]

Dieng Volcanic Complex (Indonesia). CVGHM reported that on 29 May gas plumes rose 50 m above Timbang, a cone that is part of the Dieng Volcanic Complex. The gas plumes drifted S through the valley. Observers who visited the cone noted damaged vegetation and dead birds. Seismicity and carbon dioxide gas emissions remained elevated. CVGHM raised the Alert Level to 3 (on a scale of 1-4). According to news articles, about 1,200 people were evacuated from the flanks. [GVP: Dieng Volcanic Complex]

Grímsvötn (Iceland). According to scientists from the Institute of Earth Sciences at the University of Iceland and the Icelandic Meteorological Office, explosive activity occurred from four tephra cones surrounded by water in Grímsvötn’s crater during the evening of 24 May. Pulsating ash plumes rose a few kilometres above the cones, producing only local fallout of material. Seismic tremor decreased. On 25 May observers noted steam bursts from the crater. Tephra fallout was noted only in the vicinity of the eruption site. Pilots reported widespread ash in layers 5-7 km W of the volcano and also some ash haze below 3 km (9,800 ft) a.s.l. to the SW. Seismic tremor decreased considerably. On 26 May minor steam explosions continued from the crater. According to news articles air traffic disruption was reduced to parts of Norway and Sweden. On 28 May tremor rapidly decreased then disappeared, and on 30 May participants on the Iceland Glaciological Society’s spring expedition confirmed that the eruption had ended. Satellite imagery and visual observations showed that only small amounts of ice melted during the eruption; no signs of flooding had been detected. [GVP: Grímsvötn]

Kliuchevskoi (Russia). Based on video data and ground-based observations, KVERT reported that on 29 May an ash plume from Kliuchevskoi rose to an altitude of 5 km (16,400 ft) a.s.l. and drifted SW. The Aviation Colour Code was raised to Orange. No activity was noted on 30 May and the volcano was obscured by clouds the next day. The Aviation Colour Code was lowered to Yellow. [GVP: Kliuchevskoi]

Ulawun (Papua New Guinea). RVO reported that during 23-27 May gray ash plumes rose above Ulawun’s summit crater. Fine ash fell in Ubili and Ulamona on the NW flank on 26 May. [GVP: Ulawun]


Batu Tara (Indonesia). Based on analyses of satellite imagery, the Darwin VAAC reported that during 24-27 May ash plumes from Batu Tara rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted less than 40 km W, NW, and N. [GVP: Batu Tara]

Karymsky (Russia). KVERT reported moderate seismic activity at Karymsky during 20-27 May. Possible ash plumes rose to an altitude of 6.5 km (21,300 ft) a.s.l. on 21 May and to an altitude of 3.5 km (11,500 ft) a.s.l. on the other days. Satellite imagery showed a thermal anomaly during 19-20, 22 and 24 May, and ash plumes that drifted 38 km SW on 22 May. The Aviation Colour Code remained at Orange. [GVP: Karymsky]

Kilauea (Hawaii, USA). HVO reported that two lava lakes at Kilauea were active during 25-31 May. The level of the summit lava lake remained mostly stable deep in the vent inset within the E wall of Halema’uma’u Crater. An increase in the lake level covered the vent on the south side wall during 25-28 May. On other days lava from the vent cascaded down into the lake. A gas plume from the vent drifted SW. The (preliminary) sulphur dioxide emission rate from all east rift zone sources was 700 tonnes/day on 26 May; the emission rates were slowly increasing. Lava from a vent near the W edge of the perched lava lake in the center of Pu’u ‘O’o crater floor continued to fill the lake. The lake level fluctuated and occasionally overflowed the edges or flowed through rim breaches, sending lava onto the Pu’u ‘O’o crater floor. The rim of the perched lava lake was elevated 10 m higher than the surrounding crater floor, which was 52 m below the E crater rim on 11 May. During 27-29 May lava from a vent at the base of the SW wall produced lava flows that slowly began filling the gap between the crater wall and the perched lake wall. [GVP: Kilauea]

Kizimen (Russia). KVERT reported that during 20-27 May seismicity from Kizimen was above background levels. Strong tremor was detected on 12 May; tremor amplitude gradually increased from 18 May to 24 May. Satellite images showed a large bright thermal anomaly daily on the volcano during 21-24 and 26 May. The Aviation Colour Code remained at Orange. [GVP: Kizimen]

Popocatépetl (Mexico). CENAPRED reported that on 30 May an ash plume from Popocatépetl rose 800 m above the crater and drifted E. [GVP: Popocatépetl]

Poás (Costa Rica). According to a news article, a team of geologists and volcanologists from the Universidad de Costa Rica (UCR) visited Poás on 25 May and observed 18 phreatic eruptions from Laguna Caliente (the summit lake) in a three-hour period. [GVP: Poás]

Sakura-jima (Japan). Based on information from JMA, the Tokyo VAAC reported that during 25-30 May explosions from Sakura-jima frequently produced plumes that rose to altitudes of 1.2-2.4 km (4,000-8,000 ft) a.s.l. Plumes drifted N, NW, E, SE, and S. On 27 May, a pilot observed an ash plume that rose to an altitude of 2.7 km (9,000 ft) a.s.l. and drifted E. [GVP: Sakura-jima]

Shiveluch (Russia). KVERT reported that during 20-27 May seismic activity at Shiveluch did not exceed background levels. Strong gas-and-steam activity was observed on 21 May; cloud cover prevented ground-based observations on the other days. Satellite imagery showed ash plumes drifting 58 km SW on 20 May and a thermal anomaly over the lava dome during 19-21 and 24 May. The Aviation Colour Code remained at Orange. [GVP: Shiveluch]

Taal (Philippines). PHIVOLCS reported that field measurements conducted on 24 May at the E sector inside Taal’s Main Crater Lake showed that the water temperature slightly increased from 32.5 to 32.8 degrees Celsius, the pH value became more slightly acidic decreasing from 2.83 to 2.67, and the water level increased by 4 cm. During 25-29 May between 6 and 10 daily volcanic earthquakes were detected by the seismic network. Some of the earthquakes were felt by nearby residents on the SE part of the island. During 29-30 May, 115 earthquakes were recorded. Twelve of these events were felt at Intensity I-IV by residents of Pira-piraso, Alas-as, and Calauit located in the NE, SW, and SE sectors of Volcano Island, respectively. During 30-31 May there were 31 earthquakes noted. The Alert Level remained at 2 (on a scale of 0-5). [GVP: Taal]

Tungurahua (Ecuador). The IG reported that during 24-26 May explosions from Tungurahua were detected by the seismic network. On 24 May an ash plume rose to an altitude of 7 km (23,000 ft) a.s.l. Ashfall was reported in areas SW and W. The next day an ash plume drifted W. On 26 May ash plumes were not observed due to cloud cover but ashfall was reported to the SW; cloud cover prevented observations during 27-29 May. Muddy water was observed in multiple drainages during 26-30 May. Lahars on 27 May caused the highway to Baños to close. The highway remained closed during the next two days due to lahar risk. [GVP: Tungurahua]

The foregoing is a summary of the Smithsonian Institution/United States Geological Survey Weekly Volcanic Activity Report covering 25-31 May 2011. 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.

The Volcanism Blog


1. parclair - 2 June 2011

Welcome back. Best wishes to you.

2. admin - 3 June 2011

Hi, Parclair. Many thanks!

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