Volcano Update from Archive



AVO/USGS Volcanic Activity Notice

Volcano: Shishaldin (CAVW #1101-36-)

Current Volcano Alert Level: ADVISORY
Previous Volcano Alert Level: NONE

Current Aviation Color Code: YELLOW
Previous Aviation Color Code: NONE

Issued: Tuesday, January 6, 2009, 3:28 PM AKST (20090107/0028Z)
Source: Alaska Volcano Observatory
Notice Number: 2009/A2
Location: N 54 deg 45 min W 163 deg 58 min
Elevation: 9373 ft (2857 m)
Area: Aleutians Alaska

Volcanic Activity Summary: AVO has detected a significant thermal anomaly and a slight increase in earthquake activity at Shishaldin Volcano on Unimak Island in the eastern Aleutians. Together, these observations indicate a departure from background conditions at Shishaldin. AVO is raising the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY. There is no indication that an eruption is imminent or certain, although the potential for an eruption has increased. AVO will continue to monitor the volcano closely.

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 10 miles (16 km). A small summit crater typically emits a noticeable steam plume with occasional small amounts of ash. Shishaldin is one of the most active volcanoes in the Aleutian volcanic arc, erupting atleast 28 times since 1775. Most of Shishaldin's eruptions have consisted of small ash and steam plumes, although the most recent eruption in April-May 1999 produced an ash column that reached a height of 45,000 ft above sea level.

Contacts: Peter Cervelli, Acting Scientist-in-Charge, USGS
pcervelli@usgs.gov (907) 786-7497

Jon Dehn, Acting Coordinating Scientist, UAFGI
jdehn@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

The Alaska Volcano Observatory is a cooperative program of the U.S. Geological Survey, the University of Alaska Fairbanks Geophysical Institute, and the Alaska Division of Geological and Geophysical Surveys.
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued:(20090107/0028Z)
(3) Volcano:Shishaldin (CAVW# 1101-36-)
(4) Current Color Code:YELLOW
(5) Previous Color Code:
(6) Source:Alaska Volcano Observatory
(7) Notice Number:2009/A2
(8) Volcano Location:N 54 deg 45 min W 163 deg 58 min
(9) Area:Aleutians Alaska
(10) Summit Elevation:9373 ft (2857 m)
(11) Volcanic Activity Summary:AVO has detected a significant thermal anomaly and a slight increase in earthquake activity at Shishaldin Volcano on Unimak Island in the eastern Aleutians. Together, these observations indicate a departure from background conditions at Shishaldin. AVO is raising the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY. There is no indication that an eruption is imminent or certain, although the potential for an eruption has increased. AVO will continue to monitor the volcano closely.
(12) Volcanic cloud height:Unknown
(13) Other volcanic cloud information:Unknown
(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 10 miles (16 km). A small summit crater typically emits a noticeable steam plume with occasional small amounts of ash. Shishaldin is one of the most active volcanoes in the Aleutian volcanic arc, erupting atleast 28 times since 1775. Most of Shishaldin's eruptions have consisted of small ash and steam plumes, although the most recent eruption in April-May 1999 produced an ash column that reached a height of 45,000 ft above sea level.
(15) Contacts:Peter Cervelli, Acting Scientist-in-Charge, USGS
pcervelli@usgs.gov (907) 786-7497

Jon Dehn, Acting Coordinating Scientist, UAFGI
jdehn@gi.alaska.edu (907) 474-6499
(16) 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