(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued:	(20080803/0035Z)
(3) Volcano:	Okmok (VNUM #311290)
(4) Current Color Code:	ORANGE
(5) Previous Color Code:	RED
(6) Source:	Alaska Volcano Observatory
(7) Notice Number:	2008/A20
(8) Volcano Location:	N 53 deg 23 min W 168 deg 9 min
(9) Area:	Aleutians
(10) Summit Elevation:	3520 ft (1073 m)
(11) Volcanic Activity Summary:	The episode of strong volcanic tremor at Okmok that peaked at about 4:30 AKDT (12:30 UTC) has declined in intensity. Occasional bursts of tremor, lasting from 2-5 minutes are still occurring but these do not appear to be associated with large ash emissions reaching above 20,000 feet. Satellite and local observations indicate a lower level dark ash plume and a slightly higher steam plume. Although it remains possible for ash emissions to extend to 30,000 feet or higher, the overall trend of the seismicity suggests that lower level ash plumes will be more common.
(12) Volcanic cloud height:
(13) Other volcanic cloud information:
(14) Remarks:
(15) Contacts:	Chris Waythomas, Acting Scientist-in-Charge, USGS chris@usgs.gov, (907)786-7497 Jon Dehn, Acting Coordinating Scientist, UAFGI dehn@gi.alaska.edu (907) 474-6499
(16) Next Notice:	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

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AVO/USGS Volcanic Activity Notice

Volcano: Okmok (VNUM #311290)

Current Volcano Alert Level: WATCH
Previous Volcano Alert Level: WARNING

Current Aviation Color Code: ORANGE
Previous Aviation Color Code: RED

Issued: Saturday, August 2, 2008, 4:35 PM AKDT
Source: Alaska Volcano Observatory
Notice Number: 2008/A20
Location: N 53 deg 23 min W 168 deg 9 min
Elevation: 3520 ft (1073 m)
Area: Aleutians

Volcanic Activity Summary: The episode of strong volcanic tremor at Okmok that peaked at about 4:30 AKDT (12:30 UTC) has declined in intensity. Occasional bursts of tremor, lasting from 2-5 minutes are still occurring but these do not appear to be associated with large ash emissions reaching above 20,000 feet.

Satellite and local observations indicate a lower level dark ash plume and a slightly higher steam plume.

Although it remains possible for ash emissions to extend to 30,000 feet or higher, the overall trend of the seismicity suggests that lower level ash plumes will be more common.

Contacts: Chris Waythomas, Acting Scientist-in-Charge, USGS
chris@usgs.gov, (907)786-7497

Jon Dehn, Acting Coordinating Scientist, UAFGI
dehn@gi.alaska.edu (907) 474-6499



Next Notice: 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

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