ALASKA VOLCANO OBSERVATORY WEEKLY UPDATE
U.S. Geological Survey
Friday, August 10, 2012, 10:58 AM AKDT (Friday, August 10, 2012, 18:58 UTC)
52°49'20" N 169°56'42" W,
Summit Elevation 5676 ft (1730 m)
Current Volcano Alert Level: WATCH
Current Aviation Color Code: ORANGE
A small explosive event at Cleveland volcano occurred Saturday August 4, at 8:38 AM ADT (16:38 UTC) based on retrospective analysis of infrasound data. Satellite images show a brief, faint steam plume about 4 hours after the event. Although mostly cloudy this week, satellite data showed elevated surface temperatures throughout the week. AVO has received no reports of activity from mariners or pilots in the vicinity of the volcano.
Sudden explosions of blocks and ash remain possible with little or no warning. Associated ash clouds could exceed 20,000 feet above sea level. If a large ash-producing event occurs, nearby seismic, infrasound, or volcanic lightning networks should detect the event and alert AVO staff. There is no real-time seismic monitoring network on Mount Cleveland and AVO is unable to track activity in real time.
Cleveland volcano forms the western half of Chuginadak Island, a remote and uninhabited island in the east central Aleutians. It is located about 75 km (45 mi.) west of the community of Nikolski, and 1500 km (940 mi.) southwest of Anchorage. The volcano's most recent significant eruption began in February, 2001 and it produced 3 explosive events that produced ash clouds as high as 12 km (39,000 ft) above sea level. The 2001 eruption also produced a rubbly lava flow and hot avalanche that reached the sea. The most recent minor ash emissions were observed in December 2011.
60°1'55" N 153°5'30" W,
Summit Elevation 10016 ft (3053 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW
No unusual activity has been observed or reported at Iliamna Volcano over the past week.
The current level of activity at Iliamna does not indicate an imminent or certain eruption. Seismic activity appears to be declining gradually. A similar seismic swarm occurred at Iliamna Volcano in 1996-1997 and was not followed by eruptive activity. Prior to an eruption, AVO would expect to see a significant increase in earthquake activity beneath the volcano.
Iliamna volcano is located on the western side of lower Cook Inlet in the Lake Clark National Park. Iliamna is a snow-covered stratovolcano which rises 10,020 feet above sea level. Although steam plumes occur on its eastern flanks, there has been no historic volcanic activity at Iliamna. Iliamna is located 225 km (140 miles) southwest of Anchorage and 113 km (70 miles) northwest of Homer.
OTHER ALASKA VOLCANOES
Seismic activity is monitored in real time at 29 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, Aniakchak, Augustine, Dutton, Fisher, Fourpeaked, Gareloi, Great Sitkin, Griggs, Isanotski, Kanaga, Katmai, Mageik, Makushin, Martin, Novarupta, Okmok, Pavlof, Redoubt, Shishaldin, Snowy, Spurr, Tanaga, Trident, Ugashik-Peulik, Ukinrek Maars, Veniaminof, and Westdahl 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
Christopher Waythomas, Acting Scientist-in-Charge, USGS
email@example.com (907) 786-7497
Jeff Freymueller, Coordinating Scientist, UAFGI
firstname.lastname@example.org (907) 474-7286
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.