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

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

Weekly Update

Friday, September 29, 2006 3:25 PM AKDT (2325 UTC)




FOURPEAKED VOLCANO (CAVW#1102-26-)

58°46'12" N153°40'19" W, Summit Elevation 6903 ft (2104 m)

Current Level of Concern Color Code: YELLOW

Current Volcanic Activity Alert Level: Advisory



Volcanic unrest continues at Fourpeaked volcano. Despite poor weather since our last visit to the volcano on Monday, satellite observations by scientists from the University of Maryland-Baltimore County indicate that sulfur dioxide emission is continuing.



Early in the week, AVO conducted several helicopter and fixed-wing missions to Fourpeaked. Observers photographed a linear series of vents running north from the summit for about 1 km (0.6 mi). Some of the vents were vigorously emitting steam and other volcanic gasses. Thermal measurements of up to 75 degrees C (167 degrees F) were recorded at the vents, although steam was likely obscuring hotter areas.



Adjacent glacial ice had been disrupted and showed signs of subsidence. Airborne gas measurements documented high emission rates of sulfur dioxide, hydrogren sulfide, and carbon dioxide, and a distinct sulfur smell was evident up to 50 km (30 mi) from Fourpeaked's summit. Deep scouring of a glacier flowing west from the summit indicated flooding, probably from the September 17th event.



Together, these observations strongly suggest the presence of new magma at shallow levels beneath the volcano. It remains possible that a significant eruption could occur in the coming days or weeks.



In addition to making observations this week, AVO staff have installed several seismic stations and a time-lapse camera and sampled ash and debris flow deposits from the September 17 event. Seismic data retrieved thus far indicates very low rates of volcanic earthquakes.



As weather allows, AVO will obtain further airborne gas measurements, install additional instrumentation, retrieve time-lapse images, and conduct further geologic investigations near the volcano.



Fourpeaked volcano is not known to have erupted in the last 10,000 years, although geological investigations have been limited and ice covers much of the area. Because of this, the range of sizes and styles of past eruptions are not well-constrained. However, the composition of the volcano indicates that eruptions of Fourpeaked can be explosive, possibly producing plumes that reach in excess of 10 km (33,000 ft) above sea level and local ashfall.





VENIAMINOF VOLCANO (CAVW#1102-07-)

56°11'44" N159°23'18" W, Summit Elevation 8225 ft (2507 m)

Current Level of Concern Color Code: YELLOW

Current Volcanic Activity Alert Level: Advisory



During this past week, seismicity at Veniaminof remained low, but above background. Cloudy weather persisted for much of the week, however occasional clear satellite and web camera views showed a small, white steam plume and no signs of ash emission.



Intermittent, short-lived, very small-volume steam and ash bursts from the intracaldera cone have been common over the past few years. Ash from these events is not likely to extend beyond the caldera rim. There are no indications that a larger eruption is imminent.





CLEVELAND VOLCANO (CAVW#1101-24-)

52°49'24" N169°56'35" W, Summit Elevation 5676 ft (1730 m)

Current Level of Concern Color Code: YELLOW

Current Volcanic Activity Alert Level: Advisory



Cleveland was obscured by clouds for most of the week. A few clear satellite views showed nothing unusual.



Cleveland volcano has produced brief, explosive eruptions sending ash clouds to elevations of 10,000 to 20,000 ft ASL on at least five occasions since February 2006 with the most recent confirmed explosion occurring on August 24, 2006. Additional short-lived, low-level ash explosions (less than 10,000 feet ASL) could continue intermittently for months or years



There is no real-time seismic network at Cleveland and AVO is unable to track local earthquake activity that may indicate volcanic unrest. Short-lived ash explosions may occur without warning and may go undetected on satellite imagery. Should significant activity send ash above 20,000 feet, detection by satellite is more likely.





OTHER ALASKA VOLCANOES



Seismic activity is monitored in real time at 30 volcanoes in Alaska. Satellite images of all Alaskan volcanoes are analyzed daily for evidence of ash plumes and elevated surface temperatures. Some volcanoes may currently display anomalous behavior but are not considered to be at a dangerous level of unrest. Wrangell, Spurr, Redoubt, Iliamna, Augustine, Snowy, Griggs, Katmai, Novarupta, Trident, Mageik, Martin, Peulik, Ukinrek Maars, Aniakchak, Pavlof, Dutton, Isanotski, Shishaldin, Fisher, Westdahl, Akutan, Makushin, Okmok, Korovin, Great Sitkin, Kanaga, Tanaga, and Gareloi volcanoes are in color code GREEN. All are at or near normal levels of background seismicity. AVO did not detect ash plumes or significant elevated surface temperatures in the vicinity of any volcano.



Please see http://www.avo.alaska.edu/color_codes.php for complete definitions of Aviation color codes and Volcanic activity alert levels.



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

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
URL: avo.alaska.edu/activity/avoreport_archives.php
Page modified: June 11, 2012 11:50
Contact Information: AVO Web Team

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