Friday, December 30, 2011

Alaska's Cleveland Volcano Has Minor Explosion


News from AVO and CNN confirm with NASA satellite pictures that Cleveland volcano in the Aleutian Islands of Alaska had a minor explosion. Pictures from AVO show a large plume over the summit of the volcano emitting from the summit crater area, with the ash cloud moving SSE. No other information was provided due to the remoteness of the volcano. Image from AVO (Below) shows the infrared satellite data.

                              

(Image from AVO showing gas/ash/steam plume on radar)

The current statement from AVO reads as follows:

"A detached drifting ash cloud to approximately 15,000 ft ASL has been detected at Cleveland Volcano in satellite images from 1402 UTC, Dec 29. As of 1445 UTC the ash cloud was approximately 80 KM/50 miles moving ESE from the volcano. 

Based on the presence of an ash cloud, AVO has raised the aviation color code at Cleveland Volcano to ORANGE and alert level WATCH.


Satellite data indicate that this is a single explosion event, however, more sudden explosions producing ash could occur with plumes exceeding 20,000 feet above sea level. Such explosions and their associated ash clouds may go undetected in satellite imagery for hours. However, in cooperation with the University of Washington, AVO has implemented a lightning alarm system that may detect significant ash-producing events within minutes of onset. If a large explosive event occurs, seismic signals may be recorded on AVO seismic networks at nearby volcanoes. There is no real-time seismic monitoring network at Cleveland.

Additional information on Cleveland Volcano and the current activity may be found at this link:
http://www.avo.alaska.edu/activity/Cleveland.php

Please see http://www.avo.alaska.edu/color_codes.php for complete definitions of Aviation color codes and Volcano alert levels."


The volcano has been showing signs of activity for nearly a year now, with a lava dome being extruded at the summit during the last time the volcano was at ORANGE alert level. It was recently downgraded to "Yellow" however AVO stated that activity could resume anytime in the form of explosions, dome collapse, or avalanches (I guess they were right!). Cleveland volcano is one of Alaska's most active in the Aleutian Island chain, having had multiple eruptions this decade alone.

Due to its remoteness, it is unlikely to affect life in Alaska much, save from a few diverted flight patterns, and the chance of light ashfall should the cloud blow over any populated area. The winds are currently blowing away from land, out into the Pacific ocean.

Given the recent trend of activity, it is probable that dome collapse and a minor explosion have occurred, but satellite pictures will tell us that story later. It is likely that Cleveland will remain under ORANGE alert for a while, until AVO can confirm the eruption is over or subsiding. Cleveland's summit is usually at least steaming, and satellites regularly record elevated temperatures at the crater. This volcano can have very short, or very long duration eruptions, and with no seismic or other equipment on the island itself, it is near impossible to make any observations except satellite on the island, or the occasional boat or plane that goes near it.

*****UPDATE 12/31/11*****

AVO has lowered the alert code to YELLOW down from ORANGE stating:

"2011-12-30 14:43:07 - Weekly Update
Earlier today, AVO lowered the aviation color code to YELLOW and alert level to ADVISORY for Cleveland Volcano. No new explosive activity has been observed at the volcano since the ash cloud that was detected yesterday morning.

More sudden explosions producing ash or ejecting blocks may still occur with plumes exceeding 20,000 feet above sea level. Such explosions and their associated ash clouds may go undetected in satellite imagery for hours. However, in cooperation with the University of Washington, AVO has implemented a lightning alarm system that may detect significant ash-producing events within minutes of onset. If a large explosive event occurs, seismic signals may be recorded on AVO seismic networks at nearby volcanoes. There is no real-time seismic monitoring network at Cleveland.

Additional information on Cleveland Volcano and the current activity may be found at this link:
http://www.avo.alaska.edu/activity/Cleveland.php

Please see http://www.avo.alaska.edu/color_codes.php for complete definitions of Aviation color codes and Volcano alert levels."

No reason for the quick lowering of the code was given.

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