Printer friendly versionALASKA VOLCANO OBSERVATORY
Friday, May 6, 2005 11:55 AM AKDT (19:55 UTC)
MOUNT SPURR VOLCANO
61°18' N 152°15' W, Summit Elevation 11,070 ft (3,374 m)
Current Level of Concern Color Code: YELLOW
Elevated levels of seismicity continue to be recorded at Mount Spurr. Other than the debris flow feature described below, no unusual activity was observed in satellite and web camera images this week although cloudy conditions persisted much of the week. Conditions at Crater Peak and Mount Spurr do not indicate that an eruption is imminent.
A pilot report received Monday (5/2) described a debris flow feature on the flanks of Mount Spurr below summit. AVO staff were able to see this feature from Anchorage using high-powered binoculars prompting an overflight of the volcano. Despite some cloud cover, AVO staff observed an approximately 500 meter long debris flow emanating from the ice and snow at about 9500 ft ASL east-southeast of the summit melt pit. This debris flow is similar in size and location to those observed in July 2004, just prior to first recognition of the summit melt pit. Clear views of the melt pit showed increased steam emanating from recently exposed rock around the lake which coalesced to form a weak steam plume that rose above the rim of the melt pit. It was also discovered that the lake level had decreased since our April 25 overflight. This lake level drop indicates outflow of water from the lake which may have coincided with emplacement of the recent debris flow. Analysis of web camera images suggest that the debris flow occurred late on the morning of May 2. Comparative images showing lake level drop and a video stream of web camera images showing the debris flow emplacement can be found on our website: http://www.avo.alaska.edu/
Both Spurr and Crater Peak are emitting volcanic gases, including carbon dioxide (CO2), sulfur dioxide (SO2), and hydrogen sulfide (H2S) which may be hazardous to recreational visitors. Skiers, snowboarders, mountaineers, and pilots (especially those landing near the summit area) will find information regarding proximal hazards online at: http://www.avo.alaska.edu/activity/Spurr.php
Mount Spurr volcano is an ice- and snow-covered stratovolcano located on the west side of Cook Inlet. The only known historical eruptions occurred in 1953 and 1992 from the Crater Peak flank vent located 3.5 km (2 mi) south of the summit of Mount Spurr. These eruptions were brief, explosive, and produced columns of ash that rose up to 20 km (65,000 ft) above sea level and deposited several mm of ash in south-central Alaska, including approximately 6 mm of ash on Anchorage in 1953. The last known eruption from the summit of Mount Spurr was more than 5,000 years ago. Primary hazards during future eruptions include far-traveled ash clouds, ash fall, pyroclastic flows, and lahars or mudflows that could inundate drainages all sides of the volcano, but primarily on the south and east flanks.
OTHER ALASKA VOLCANOES
Seismic activity is monitored in real time at 28 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, Redoubt, Iliamna, Augustine, Snowy, Griggs, Katmai, Novarupta, Trident, Mageik, Martin, Peulik, Aniakchak, Veniaminof, Pavlof, Dutton, Isanotski, Shishaldin, Fisher, Westdahl, Akutan, Makushin, Okmok, 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.
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
Tom Murray, Scientist-in-Charge, USGS, firstname.lastname@example.org (907) 786-7497
John Eichelberger, Coordinating Scientist, UAF-GI, email@example.com (907) 474-5530
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.