(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued:(20080802/2335Z)
(3) Volcano:Okmok (CAVW# 1101-29-)
(4) Current Color Code:ORANGE
(5) Previous Color Code:
(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 Alaska
(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:Unknown
(13) Other volcanic cloud information:Unknown
(14) 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

(15) Next Notice:A new VONA will be issued if conditions change significantly or alert levels are modified. While a VONA is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu