|(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)|
|(3) Volcano:||Semisopochnoi (VNUM #311060)|
|(4) Current Color Code:||ORANGE|
|(5) Previous Color Code:||YELLOW|
|(6) Source:||Alaska Volcano Observatory|
|(7) Notice Number:|
|(8) Volcano Location:||N 51 deg 55 min E 179 deg 35 min|
|(10) Summit Elevation:||2625 ft (800 m)|
|(11) Volcanic Activity Summary:||Elevated seismicity that started yesterday has intensified over the past couple of hours, and a strong tremor signal at 20:49 UTC (12:49 AKDT) suggests that ash emissions may be occurring or are imminent at Semisopochnoi. Thus we are raising the Aviation Color Code to ORANGE and the Volcano Alert Level to WATCH.
Nothing has been detected in satellite, lightning, or infrasound data.
|(12) Volcanic cloud height:||Unknown|
|(13) Other volcanic cloud information:||Unknown|
|(14) Remarks:||Semisopochnoi is monitored with an on-island seismic network, and remotely by satellite and lightning sensors. An infrasound array on Adak Island could detect explosive emissions from Semisopochnoi with a 13 minute delay if atmospheric conditions permit.|
|(15) Contacts:||Michelle Coombs, Scientist-in-Charge, USGS
firstname.lastname@example.org (907) 786-7497
David Fee, Coordinating Scientist, UAFGI
email@example.com (907) 322-4085
|(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
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