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AVO/USGS Volcanic Activity Notice

Volcano: Okmok (CAVW #1101-29-)

Current Volcano Alert Level: WARNING

Current Aviation Color Code: RED

Issued: Sunday, July 13, 2008, 8:24 AM AKDT (20080713/1624Z)
Source: Alaska Volcano Observatory
Notice Number: 2008/A9
Location: N 53 deg 23 min W 168 deg 9 min
Elevation: 3520 ft (1073 m)
Area: Aleutians Alaska

Volcanic Activity Summary: The eruption at Okmok continues based on high levels of seismicity and ash continues to be erupted as indicated in satellite observations. Seismicity reached a peak at about 2200 Z (2:00 PM ADT) yesterday and has been gradually declining since. Reports from Unalaska indicate no ash fall in Unalaska/Dutch Harbor since last night. However, as of 0730 ADT the ash fall advisory for Nikolski and Unalaska/Dutch Harbor remains in effect.

Recent Observations:
[Volcanic cloud height] National Weather Service reports plume height to be up to 45,000 ft. above sea level.

[Ash fall] Reports from Unalaska indicate no ash fall in Unalaska/Dutch Harbor since last night. However, as of 0730 ADT the ash fall advisory for Nikolski and Unalaska/Dutch Harbor remains in effect.

Hazard Analysis:
[General hazards] Ash fall is expected to continue downwind of the volcano including over marine areas in the North Pacific. Areas in the immediate vicinity of the volcano on Umnak Island should be avoided, particularly the Crater Creek drainage northeast of the caldera.

[Ash cloud] An ash cloud is drifting southeast and east of the volcano and poses a risk to aircraft in the vicinity. The estimated cloud height for the ash cloud is up to 45,000 ft above sea level.

[Ballistics] Ballistics may impact the areas around the caldera rim.

[Lava flow/dome] Historical eruptions of Okmok have typically produced lava flows, however at this time we cannot confirm that a lava flow has been produced.

Remarks: Okmok Volcano is located on the northeast end of Umnak Island in the eastern Aleutians about 65 miles southwest of Unalaska/Dutch Harbor. The volcano consists of a 6-mile-wide circular caldera or crater about 1600 feet deep that formed about 2000 years ago. Okmok has been frequently active in historical times producing ash clouds often accompanied by lava flows within the caldera. The most recent eruption occurred in 1997 and produced ash clouds and a lava flow that traveled about 5 miles across the caldera floor.

Please see http://www.avo.alaska.edu/activity/Okmok.php for more information.

Contacts:

John Power, Acting Scientist-in-Charge, USGS
jpower@usgs.gov (907) 786-7497

Steve McNutt, Coordinating Scientist, UAF
steve@giseis.alaska.edu (907) 474-7131

Next Notice: More information will be released as it is received.
A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu

The Alaska Volcano Observatory is a cooperative program of the U.S. Geological Survey, the University of Alaska Fairbanks Geophysical Institute, and the Alaska Division of Geological and Geophysical Surveys.


AVO/USGS Volcanic Activity Notice

Volcano: Okmok (CAVW #1101-29-)

Current Volcano Alert Level: WARNING

Current Aviation Color Code: RED

Issued: Sunday, July 13, 2008, 8:24 AM AKDT (20080713/1624Z)
Source: Alaska Volcano Observatory
Notice Number: 2008/A9
Location: N 53 deg 23 min W 168 deg 9 min
Elevation: 3520 ft (1073 m)
Area: Aleutians Alaska

Volcanic Activity Summary: The eruption at Okmok continues based on high levels of seismicity and ash continues to be erupted as indicated in satellite observations. Seismicity reached a peak at about 2200 Z (2:00 PM ADT) yesterday and has been gradually declining since. Reports from Unalaska indicate no ash fall in Unalaska/Dutch Harbor since last night. However, as of 0730 ADT the ash fall advisory for Nikolski and Unalaska/Dutch Harbor remains in effect.

Recent Observations:
[Volcanic cloud height] National Weather Service reports plume height to be up to 45,000 ft. above sea level.

[Ash fall] Reports from Unalaska indicate no ash fall in Unalaska/Dutch Harbor since last night. However, as of 0730 ADT the ash fall advisory for Nikolski and Unalaska/Dutch Harbor remains in effect.

Hazard Analysis:
[General hazards] Ash fall is expected to continue downwind of the volcano including over marine areas in the North Pacific. Areas in the immediate vicinity of the volcano on Umnak Island should be avoided, particularly the Crater Creek drainage northeast of the caldera.

[Ash cloud] An ash cloud is drifting southeast and east of the volcano and poses a risk to aircraft in the vicinity. The estimated cloud height for the ash cloud is up to 45,000 ft above sea level.

[Ballistics] Ballistics may impact the areas around the caldera rim.

[Lava flow/dome] Historical eruptions of Okmok have typically produced lava flows, however at this time we cannot confirm that a lava flow has been produced.

Remarks: Okmok Volcano is located on the northeast end of Umnak Island in the eastern Aleutians about 65 miles southwest of Unalaska/Dutch Harbor. The volcano consists of a 6-mile-wide circular caldera or crater about 1600 feet deep that formed about 2000 years ago. Okmok has been frequently active in historical times producing ash clouds often accompanied by lava flows within the caldera. The most recent eruption occurred in 1997 and produced ash clouds and a lava flow that traveled about 5 miles across the caldera floor.

Please see http://www.avo.alaska.edu/activity/Okmok.php for more information.

Contacts:

John Power, Acting Scientist-in-Charge, USGS
jpower@usgs.gov (907) 786-7497

Steve McNutt, Coordinating Scientist, UAF
steve@giseis.alaska.edu (907) 474-7131

Next Notice: More information will be released as it is received.
A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu

The Alaska Volcano Observatory is a cooperative program of the U.S. Geological Survey, the University of Alaska Fairbanks Geophysical Institute, and the Alaska Division of Geological and Geophysical Surveys.
VOLCANO ALERT LEVELS
NORMAL
Volcano is in typical background, noneruptive state or, after a change from a higher level, volcanic activity has ceased and volcano has returned to noneruptive background state.
ADVISORY
Volcano is exhibiting signs of elevated unrest above known background level or, after a change from a higher level, volcanic activity has decreased significantly but continues to be closely monitored for possible renewed increase.
WATCH
Volcano is exhibiting heightened or escalating unrest with increased potential of eruption, timeframe uncertain, OR eruption is underway but poses limited hazards.
WARNING
Hazardous eruption is imminent, underway, or suspected.
AVIATION COLOR CODES
GREEN
Volcano is in typical background, noneruptive state or, after a change from a higher level, volcanic activity has ceased and volcano has returned to noneruptive background state.
YELLOW
Volcano is exhibiting signs of elevated unrest above known background level or, after a change from a higher level, volcanic activity has decreased significantly but continues to be closely monitored for possible renewed increase.
ORANGE
Volcano is exhibiting heightened or escalating unrest with increased potential of eruption, timeframe uncertain, OR eruption is underway with no or minor volcanic-ash emissions [ash-plume height specified, if possible].
RED
Eruption is imminent with significant emission of volcanic ash into the atmosphere likely OR eruption is underway or suspected with significant emission of volcanic ash into the atmosphere [ash-plume height specified, if possible].
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URL: www.avo.alaska.edu/activity/avoreport.php
Page modified: June 17, 2015 15:03
Contact Information: AVO Web Team

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