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ALASKA VOLCANO OBSERVATORY WEEKLY UPDATE
U.S. Geological Survey
Friday, April 9, 2010, 1:13 PM AKDT (Friday, April 9, 2010, 21:13 UTC)
60°29'7" N 152°44'38" W,
Summit Elevation 10197 ft (3108 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW
The swarm of small, shallow earthquakes that began Monday, April 5 at Redoubt Volcano has greatly decreased over the past several days, and is approaching background levels of activity. A gas measurement and observation flight on Thursday, April 8 showed no disruption of the lava dome and measured gas levels were consistent with a passively degassing and cooling dome. It appears less likely that this current episode of unrest will lead to resumed eruptive activity. Although the volcano remains somewhat restless, we would expect a greater degree of seismic activity, significantly elevated gas emissions, and melting of snow and ice on the lava dome if conditions were escalating toward eruption.
The Aviation Color Code remains YELLOW and the Volcano Alert Level remains ADVISORY. AVO will continue to issue daily status reports as long as the Aviation Color Code and Alert Level are elevated.
Heavily ice-mantled Redoubt volcano is located on the western side of Cook Inlet, 170 km (106 mi) southwest of Anchorage and 82 km (51 mi) west of Kenai, within Lake Clark National Park. Redoubt is a stratovolcano which rises to 10,197 feet above sea level. Recent eruptions occurred in 1902, 1966-68, 1989-90, and 2009. The 1989-90 and 2009 eruptions produced mudflows, or lahars, that traveled down the Drift River and partially flooded the Drift River Oil Terminal facility. The ash plumes produced by the 1989-90 and 2009 eruptions significantly disrupted air traffic and resulted in minor or trace amounts of ash in the city of Anchorage and other communities in south-central and interior Alaska.
OTHER ALASKA VOLCANOES
Seismic activity is monitored in real time at 27 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. Akutan, Augustine, Dutton, Fisher, Gareloi, Great Sitkin, Griggs, Iliamna, Isanotski, Kanaga, Katmai, Mageik, Makushin, Martin, Novarupta, Okmok, Pavlof, Shishaldin, Snowy, Spurr, Tanaga, Trident, Ugashik-Peulik, Ukinrek Maars, Westdahl, and Wrangell volcanoes are in color code GREEN
and volcano alert level Normal. 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 of these volcanoes.
Please see http://www.avo.alaska.edu/color_codes.php
for complete definitions of Aviation color codes and Volcano alert levels.
VOLCANO INFORMATION ON THE INTERNET: http://www.avo.alaska.edu
RECORDING ON THE STATUS OF ALASKA'S VOLCANOES (907) 786-7478
Chris Waythomas, Acting Scientist-in-Charge, USGS
firstname.lastname@example.org (907) 786-7497
Jessica Larsen, Acting Coordinating Scientist, UAF
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.