(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
(2) Issued: | (20200119/1728Z) |
(3) Volcano: | Shishaldin (VNUM #311360) |
(4) Current Color Code: | RED |
(5) Previous Color Code: | ORANGE |
(6) Source: | Alaska Volcano Observatory |
(7) Notice Number: | 2020/A58 |
(8) Volcano Location: | N 54 deg 45 min W 163 deg 58 min |
(9) Area: | Aleutians |
(10) Summit Elevation: | 9373 ft (2857 m) |
(11) Volcanic Activity Summary: | Starting at about 09:30 UTC (12:30 AM AKST), the eruption at Shishaldin intensified, and about two hours ago began generating a more ash-rich volcanic plume. The plume now extends from the summit 150 km east and is as high as about 20,000 ft asl, as seen in satellite data. Seismicity is elevated and the eruption is detected on regional infrasound arrays. The aviation color code is being raised to RED and the volcano alert level to WARNING. The National Weather Service has issued a SIGMET for this activity. |
(12) Volcanic cloud height: | 20,000 ft asl |
(13) Other volcanic cloud information: | heading east |
(14) Remarks: | Shishaldin volcano, located near the center of Unimak Island in the eastern Aleutian Islands, is a spectacular symmetric cone with a base diameter of approximately 16 km (10 mi). A 200-m-wide (660 ft) funnel-shaped summit crater typically emits a steam plume and occasional small amounts of ash. Shishaldin is one of the most active volcanoes in the Aleutian volcanic arc, with at least 54 episodes of unrest including over 24 confirmed eruptions since 1775. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft above sea level. |
(15) Contacts: | Michelle Coombs, Scientist-in-Charge, USGS mcoombs@usgs.gov (907) 786-7497 David Fee, Coordinating Scientist, UAFGI dfee1@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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