Chaiten Volcano, Chile - John Seach

Eruptive activity at Chaiten volcano in Chile was stable on 27th February. An eruption column rose to a height of less than 2 km. During the day there were minor collapses of the spine of the dome. The collapse events led to an increase in ash content of the plume. Small dome collapses were observed at at 17:39 hr, 18:44, 18:59 and 19:35, which was the largest. Eruption columns are irregular and periodic, and are composed of gas, ash, and water vapour. There have been no changes in seismic activity at Chaiten volcano. Two earthquakes were reported on 26th February - magnitude 3.2 at a depth of 15.1 km, and magnitude 3.3 at depth of 14.4 km. The volcanic alert level for Chaiten volcano remains ar RED, due to the possibility of further ash eruptions, dome collapse, pyroclastic flows, and lahars.
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Chaiten Volcano, Chile - John Seach

Eruptive activity at Chaiten volcano in Chile remains unchanged. The southeast side of the summit lava dome remains unstable, and is liable to collapse. Dome growth continues, and a steep pinnacle has formed on the south side of the dome. Preliminary data indicates temperatures of about 270 º C at the pinnacle, and 200 º C in the southern remnant of the dome. This suggests that the magmatic activity is currently concentrated in the southern sector of the dome and at the pinnacle. Pyroclastic flow temperatures in the upper reaches of Chaiten River affected by avalanche is 130 deg C, 70 deg C in the middle of the river valley, and 50 deg C in the lower part. On 25th February at 10:30 hr, local time, there was a superficial magnitude 2.7 earthquake at Chaiten volcano.
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Chaiten Volcano, Chile - John Seach

An overflight of Chaiten volcano on 24th of February revealed more details about the 19th February dome collapse. The collapse escarpment is oriented approximately southwest, with a major axis of approximately 500 m and maximum height of the escarpment of 200 m. The area of collapse is located in the southwest sector of the dome and affected approximately 10% of the total volume. The northern sector of the dome shows low eruptive activity. Volcanic alert remains at RED due to continued seismic activity, dome growth, explosive activity, and the possibility of pyroclastic flows and lahars.
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Chaiten Volcano, Chile - John Seach

After the dome collapse at Chaiten volcano, Chile, on 19th February, seismicity returned to lower levels. The collapse mobilised a large amount of material south into Chaiten River valley. An estimated 30 million tons of material collapsed from the dome, which present a lahar hazard to Chaiten town.
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Chaiten Volcano Eruption 19th February 2009, Chile - John Seach

On Tuesday 17th February there were 9 earthquakes between magnitude 3.5 and 3.9 measured at Chaiten volcano in Chile. On Wednesday 18th there were 13 earthquakes between magnitude 3.6 and 3.9. On Thursday February 19 from 10:28 hrs to 13:46 hrs there were a swarm of earthquakes with magnitudes 3.6 to 4.2, with depths of between 3 and 5 km. Preliminary analysis showed the earthquakes were located immediately east of the volcano. In the period preceding the dome collapse, earthquakes were located south of the dome.

An important sector of the southern flank of the dome collapsed on Thursday 19th February, producing a lateral explosion and block and ash flows and pyroclastic flows, which descended south, reaching the top of the Chaitén river valley, 5 km north of the Chaiten town. In addition, eruptive column was erupted about 2 pm, reaching approximately 8 km high, and drifting southeast, and creating ashfall in the town of Futaleufu. Residents near the volcano indicated the ash plume may have reached 15-20 km high.

A Twin Otter overflight of Chaiten volcano on Thursday revealed the north flank of the volcano had a similar appearance to that of previous weeks. Towards the south flank of the volcano, partial observations revealed that forest had been burnt. A helicopter overflight revealed a 500 m x 500 m collapse of the summit dome, which generated pyroclastic flows that advanced by 4 to 5 km down the Chaiten river valley, destroying native forest. At a location in the valley 3-4 km from Chaiten town, there were 5 or 6 locations which emitted gas and water vapour. This process can be interpreted primarily as side effects of pyroclastic flows, which generated large amounts of steam when in contact with water.

In view of the continuing seismic activity associated with the eruption, along with growth and major collapses of the dome, lateral blast, block and ash flows and pyroclastic flows, Volcanic Red Alert remains in place for Chaiten volcano. Further block and ash flows and pyroclastic flows may affect Chaiten town and also to other sectors of the volcano. Ashfall may affect locations downwind from the volcano.
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Galeras Volcano, Colombia - John Seach

An eruption occurred at Galeras volcano, Colombia on 20th February 2009 at 7:05 am, local time. The eruption was accompanied by shock waves, and and vibrations in several villages located in the catchment area of the volcano. There are confirmed reports that the eruption was heard in the city of Popayan, over 150 km NNE of the volcano. There were at least two explosions, and emission of incandescent material, along with a sulphurous smell. The initial eruptive event was associated with a seismic signal which lasted for approximately 13 minutes. The seismic energy was almost twice the assessed for the eruption of 14th February 2009. Wind direction according to the weather station installed at the top of Galeras, is toward the west coast. There are reports of ash fall in areas of the municipalities of Sandona, Consacá and Ancuya, located on the western flank of Galeras. The eruptive column showed three levels of dispersion. The column reached a height of about 8 km, with dispersal to the east, at an altitude of 2500 m, the plume of ash was to the west, and between these two levels, the ash moved north. This dispersion was due to variable wind conditions at different altitudes. After the eruption there was a decrease in seismic activity, characterized by the presence of a few events associated with fluid dynamics and low energy levels. The volcanic warning level at Galeras is RED: ERUPTION IMMINENT OR IN PROGRESS.
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Chaiten Volcano, Chile - John Seach

An explosive eruption occurred at Chaiten volcano in Chile yesterday. A flyover of the volcano revealed a fracture in the lava dome, which had partially collapsed. Large quantities of gases and pyroclastic material were observed. About 160 residents were evacuated from Chaiten town, 10 km from the volcano. Most of the residents of Chaiten town evacuated last year after large eruptions in May. The volcano has been in continuous eruption since May 2008, and periodic larger explosions create a hazard for residents remaining in the area.
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Redoubt Volcano, Alaska - John Seach

A burst of volcanic tremor occurred at Redoubt volcano, Alaska on Thursday 5th February at 11:18 am (local time). The tremor lasted 4 minutes and was the most intense since January 30th. A second episode of volcanic tremor occurred just after 3:00 PM on Wednesday and lasted for about 30 minutes. No eruption accompanied the earthquakes.
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Redoubt Volcano, Alaska - John Seach

Seismicity remains elevated at Redoubt Volcano in Alaska. Melting of the glacier has produced a 200 m wide hole, which is emitting gas. The Federal Aviation Administration has issued a temporary flight restriction for a 10-mile radius around Redoubt, from ground level to 60,000 feet. During the last eruption in 1989, an aircraft flew through a plume of ash. All four engines ingested ash and flamed out. The crew successfully restarted the engines and landed safely at Anchorage. All four engines were replaced.
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Asama Volcano, Japan - John Seach

Asama volcano in Japan erupted today at 1:51 am, local time, sending ash to a height of 1.6 km, and ejecting rocks 1 km from the crater. Ashfall was reported in Tokyo, 145 km SE of the volcano.
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