Volcano Update from Archive



ALASKA VOLCANO OBSERVATORY INFORMATION STATEMENT
Friday, October 3, 2008 10:37 AM AKDT (Friday, October 3, 2008 1837 UTC)


Redoubt Volcano
60°29'7" N 152°44'38" W, Summit Elevation 10197 ft (3108 m)
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN

On September 16, a pilot flying downwind of Redoubt Volcano reported a strong hydrogen sulfide odor. A week later, residents of a cabin near Wadell Lake 15 miles (25 km) northeast of Redoubt reported loud noises coming from the direction of the volcano. In response to these reports, AVO sent an observation flight to Redoubt on September 27, which revealed several fractures and circular openings in the upper Drift glacier that had not been seen before. Scientists on the flight also noted that fumaroles atop the 1968 and 1990 domes were steaming more vigorously than when last observed in mid-August. A distinct hydrogen sulfide odor was also evident, though onboard instrumentation measured no sulfur dioxide. AVO's seismic network at Redoubt has detected no abnormal earthquake activity. A small number of rockfalls, other surface events, and infrasound waves have been observed in seismic data, though these events are within the range of normal background activity.



At this time, Redoubt Volcano remains at aviation color code GREEN and alert level NORMAL. The recent observations of increased fumarolic activity and sulfur odors do not suggest an imminent eruption at Redoubt Volcano. Though vigorous fumaroles and sulfur odors were noted in the weeks to months preceding the 1989-1990 eruption, seismicity also increased markedly. AVO expects that if the current low-level unrest does lead to an eruption, a similar strong increase in seismicity would first occur.



Redoubt is a stratovolcano located on the western side of Cook Inlet, 170 km (106 mi) southwest of Anchorage and 82 km (51 mi) east of Kenai, within Lake Clark National Park. Recent eruptions occurred in 1902, 1966-68, and 1989-90. The 1989-90 eruption produced a lahar that traveled down the Drift River and partially flooded the Drift River Oil Terminal facility. Ash plumes produced during the 1989-90 eruption affected international air traffic and resulted in a trace of ashfall on the city of Anchorage and other nearby communities.

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. Augustine, Iliamna, Redoubt, Wrangell, Gareloi, Great Sitkin, Makushin, Fisher, Shishaldin, Isanotski, Pavlof, Veniaminof, Ugashik-Peulik, Griggs, Snowy, Fourpeaked, Aniakchak, Tanaga, Kanaga, Akutan, Westdahl, Dutton, Ukinrek Maars, Martin, Mageik, Trident, Katmai, Novarupta, Spurr, and Korovin 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 volcano.



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

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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.