Printer friendly versionALASKA VOLCANO OBSERVATORY WEEKLY UPDATEFriday, April 6, 2012 10:59 AM AKDT (Friday, April 6, 2012 18:59 UTC)CLEVELAND VOLCANO
52°49'20" N 169°56'42" W, Summit Elevation 5676 ft (1730 m)
Current Volcano Alert Level: WATCH
Current Aviation Color Code: ORANGE
The low-level eruption of Cleveland continues. The small, 70-meter-diameter (230 ft) lava dome in the summit crater of Cleveland Volcano was destroyed during a short explosive eruption on April 4, which was detected by distant infrasound (air pressure) and seismic stations. The resulting ash cloud did not rise above the cloud deck, which had an estimated altitude of about 4.5 km (15,000 ft) above sea level. This is the third lava dome that has been erupted and subsequently destroyed by explosive events since the eruption began in July 2011. Elevated surface temperatures were observed in satellite images at times throughout the week, further indicating that low-level unrest continues, but there have been no observations of renewed dome growth.
While the volcano remains active, sudden explosions of blocks and ash are likely. It is possible for associated ash clouds to exceed 20,000 feet above sea level. If a larger ash-producing event occurs, 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 so 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 January and June 2009.ILIAMNA VOLCANO
60°1'55" N 153°5'30" W, Summit Elevation 10016 ft (3053 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW
Seismic activity at Iliamna Volcano remains slightly above background. Intermittent clear web camera and satellite views over the past week show no unusual activity.
The current activity at Iliamna does not indicate an imminent or certain eruption. A similar seismic swarm at Iliamna in 1996-1997 was not followed by eruptive activity. Prior to an eruption, AVO would expect to see a further increase in earthquake activity.
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) southwest of Homer.
VOLCANO INFORMATION ON THE INTERNET: http://www.avo.alaska.edu
RECORDING ON THE STATUS OF ALASKA'S VOLCANOES (907) 786-7478
John Power, Scientist-in-Charge, USGS
firstname.lastname@example.org (907) 786-7497
Mike West, Acting Coordinating Scientist, UAF
email@example.com (907) 474-6977
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.