Volcano Update from Archive



AVO/USGS Volcanic Activity Notice

Volcano: Kasatochi (CAVW #1101-13-)

Current Volcano Alert Level: WATCH
Previous Volcano Alert Level: NONE

Current Aviation Color Code: ORANGE
Previous Aviation Color Code: NONE

Issued: Thursday, August 7, 2008, 1:57 PM AKDT (20080807/2157Z)
Source: Alaska Volcano Observatory
Notice Number: 2008/A23
Location: N 52 deg 10 min W 175 deg 30 min
Elevation: 1030 ft (314 m)
Area: Aleutians Alaska

Volcanic Activity Summary: Earthquake activity in the vicinity of Kasatochi Volcano continues and is now being accompanied by periods of volcanic tremor. Volcanic tremor is often associated with fluid or magma migration. This morning, a US Fish and Wildlife Service field crew on Kasatochi Island reported periods of continuous ground shaking lasting 5-10 minutes, numerous rockfalls, and strong sulfur smell. These observations combined with the elevated seismicity suggest that an eruption is more likely and AVO is raising the color code and alert level to ORANGE/WATCH.

Remarks: AVO is monitoring this situation closely and has its operations room staffed 24 hours per day. More information about activity at Kasatochi Volcano can be found on the AVO web siteat www.avo.alaska.edu or by calling 907-786-7497.

Kasatochi Island represents the emergent summit of a predominantly submarine volcano composed of basaltic and andesitic flows and pyroclastics. Kasatochi has had no known historical eruptions; however, the volcano is mantled by a cover of young appearing pyroclastic debris indicative of relatively recent explosive activity. The island consists of a single, undissected cone with a central lake-filled crater about 0.75 km in diameter. A maximum height of 314 m is on the southern crater rim; elevation of the lake is less than about 60 m. Kasatochi Island is at the northern end of a 15-km-long, 6-km-wide submarine ridge that is normal to the trend of the Andreanof Islands. Water depths along the ridge are less than 90 m; if Kasatochi is constructed entirely on the ridge, the total height of the volcanic pile is only a little more than 400 m.

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

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:(20080807/2157Z)
(3) Volcano:Kasatochi (CAVW# 1101-13-)
(4) Current Color Code:ORANGE
(5) Previous Color Code:
(6) Source:Alaska Volcano Observatory
(7) Notice Number:2008/A23
(8) Volcano Location:N 52 deg 10 min W 175 deg 30 min
(9) Area:Aleutians Alaska
(10) Summit Elevation:1030 ft (314 m)
(11) Volcanic Activity Summary:Earthquake activity in the vicinity of Kasatochi Volcano continues and is now being accompanied by periods of volcanic tremor. Volcanic tremor is often associated with fluid or magma migration. This morning, a US Fish and Wildlife Service field crew on Kasatochi Island reported periods of continuous ground shaking lasting 5-10 minutes, numerous rockfalls, and strong sulfur smell. These observations combined with the elevated seismicity suggest that an eruption is more likely and AVO is raising the color code and alert level to ORANGE/WATCH.

(12) Volcanic cloud height:Unknown
(13) Other volcanic cloud information:Unknown
(14) Remarks:AVO is monitoring this situation closely and has its operations room staffed 24 hours per day. More information about activity at Kasatochi Volcano can be found on the AVO web siteat www.avo.alaska.edu or by calling 907-786-7497.

Kasatochi Island represents the emergent summit of a predominantly submarine volcano composed of basaltic and andesitic flows and pyroclastics. Kasatochi has had no known historical eruptions; however, the volcano is mantled by a cover of young appearing pyroclastic debris indicative of relatively recent explosive activity. The island consists of a single, undissected cone with a central lake-filled crater about 0.75 km in diameter. A maximum height of 314 m is on the southern crater rim; elevation of the lake is less than about 60 m. Kasatochi Island is at the northern end of a 15-km-long, 6-km-wide submarine ridge that is normal to the trend of the Andreanof Islands. Water depths along the ridge are less than 90 m; if Kasatochi is constructed entirely on the ridge, the total height of the volcanic pile is only a little more than 400 m.
(15) 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

(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