(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
(2) Issued: | (20200215/0919Z) |
(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 |
(9) Area: | Aleutians |
(10) Summit Elevation: | 2625 ft (800 m) |
(11) Volcanic Activity Summary: | A series of small explosions and tremor bursts have been detected in seismic data at Semisopochnoi over the past 7 hours and are continuing, representing a significant uptick in activity. No ash plumes have been observed, however low-level ash emissions may accompany these minor explosions. Any ash emissions may be currently obscured by cloud cover at ~10,000 ft. The Alaska Volcano Observatory is therefore raising the Aviation Color Code to ORANGE and the Alert Level to WATCH. |
(12) Volcanic cloud height: | No cloud observed |
(13) Other volcanic cloud information: | No cloud observed |
(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 mcoombs@usgs.gov (907) 786-7497 Taryn Lopez, Acting Coordinating Scientist, UAFGI tmlopez@alaska.edu (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 http://www.avo.alaska.edu |
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