AVO Logo
Site Map | FAQ |
Alaska Volcano Observatory
Summary | Webcams | Webicorders | RSAM | Activity Notifications | Notification Search | Cleveland | Shishaldin | Semisopochnoi 
You are here: Home > Current Volcanic Activity > Archived Volcano Activity Notifications

AVO Archived Volcano Activity Notifications

2007
December
November
October
September
August
July
June
May
April
March
February
January
2006
December
November
October
September
August
July
June
May
April
March
February
January
2005
December
November
October
September
August
July
June
May
April
March
February
January
2004
December
November
October
September
August
July
June
May
April
March
February
January
2003
2002
2001
2000
1999
1998
1997
1996
December
November
October
September
August
July
June
May
April
March
February
January
1995
1994
1993
1992
December
November
October
September
August
July
June
May
April
March
February
January
1991
1990
1989
ARCHIVED REPORT
Printer friendly version

ALASKA VOLCANO OBSERVATORY

INFORMATION RELEASE

Friday, October 7, 2005 1:20 PM AKDT (2120 UTC)




TANAGA VOLCANO (CAVW#1101-08-)

51.885°N 178.1458°W, Summit Elevation 5925 ft (1806 m)

Current Level of Concern Color Code: YELLOW

Previous Level of Concern Color Code: Green



The earthquake swarm that began at Tanaga Volcano on October 1 has increased over the past 32 hours. Marked increases in the rate of earthquake occurrence took place late on October 5 and then again at roughly 5:00 AM AKDT today. The located earthquakes range in magnitude from 0.5 to 1.9 and now range in depth from 6 to 12 km beneath the volcano’s summit. These locations represent both an increase in magnitude and a shallowing in depth compared with events recorded at Tanaga between October 1 and 5. In response to the observed changes in seismic activity the Alaska Volcano Observatory (AVO) is increasing the level of concern color code to Yellow. While the current rate of earthquake activity represents a significant increase in rate, the size, depths and character of the shocks are not indicative of imminent eruptive activity. AVO will continue to monitor the activity at Tanaga closely.



Tanaga is a remote, 1,806 m (5,925 ft)-high stratovolcano located on the northwest portion of Tanaga Island, roughly 105 km (63 miles) west of Adak in the Andreanof Islands. The last known eruption of Tanaga occurred in 1914 and earlier eruptions were reported in 1763-1770, 1791, and 1829. Reports of these eruptions are vague, but deposits on the flanks of the volcano show that typical eruptions produce blocky lava flows and occasional ash clouds. Eruptions have occurred both from the summit vent and a 1,584 m (5,197 ft)-high satellite vent on the volcano's northeast flank.



ABBREVIATED COLOR CODE KEY (contact AVO for complete description):

GREEN volcano is dormant; normal seismicity and fumarolic activity occurring

YELLOW volcano is restless; eruption may occur

ORANGE volcano is in eruption or eruption may occur at any time

RED significant eruption is occurring or explosive eruption expected at any time



VOLCANO INFORMATION ON THE INTERNET: http://www.avo.alaska.edu

RECORDING ON THE STATUS OF ALASKA'S VOLCANOES (907) 786-7478



CONTACT INFORMATION:

Tom Murray, Scientist-in-Charge, USGS

tlmurray@usgs.gov (907) 786-7497



Steve McNutt, Acting Coordinating Scientist, UAF-GI

steve@giseis.alaska.edu (907) 474-7131



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.
VOLCANO ALERT LEVELS
NORMAL
Volcano is in typical background, noneruptive state or, after a change from a higher level, volcanic activity has ceased and volcano has returned to noneruptive background state.
ADVISORY
Volcano is exhibiting signs of elevated unrest above known background level or, after a change from a higher level, volcanic activity has decreased significantly but continues to be closely monitored for possible renewed increase.
WATCH
Volcano is exhibiting heightened or escalating unrest with increased potential of eruption, timeframe uncertain, OR eruption is underway but poses limited hazards.
WARNING
Hazardous eruption is imminent, underway, or suspected.

AVIATION COLOR CODES
GREEN
Volcano is in typical background, noneruptive state or, after a change from a higher level, volcanic activity has ceased and volcano has returned to noneruptive background state.
YELLOW
Volcano is exhibiting signs of elevated unrest above known background level or, after a change from a higher level, volcanic activity has decreased significantly but continues to be closely monitored for possible renewed increase.
ORANGE
Volcano is exhibiting heightened or escalating unrest with increased potential of eruption, timeframe uncertain, OR eruption is underway with no or minor volcanic-ash emissions [ash-plume height specified, if possible].
RED
Eruption is imminent with significant emission of volcanic ash into the atmosphere likely OR eruption is underway or suspected with significant emission of volcanic ash into the atmosphere [ash-plume height specified, if possible].

PDF version of these definitions
Contact AVO Privacy Accessibility Information Quality FOIA
URL: avo.alaska.edu/activity/avoreport_archives.php
Page modified: May 27, 2014 10:23
Contact Information: AVO Web Team

twitter @alaska_avo
facebook alaska.avo
email Receive volcano updates by email: USGS VNS