ALASKA VOLCANO OBSERVATORY WEEKLY UPDATE
U.S. Geological Survey
Friday, May 11, 2018, 12:47 PM AKDT (Friday, May 11, 2018, 20:47 UTC)
52°49'20" N 169°56'42" W,
Summit Elevation 5676 ft (1730 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW
A small explosion was recorded on local seismic and infrasound sensors on Friday, May 4 at 21:49 AKDT (May 5 at 05:49 UTC) and resulted in a short-lived ash cloud that reached 22,000 ft above sea level and was distributed to the southeast. Since then, no significant activity has been detected on local seismic and infrasound sensors, although small local earthquakes have been recorded and suggest continued low-level unrest. Satellite views of the volcano were generally obscured by clouds this week.
Future explosive activity is likely and is expected to occur without warning. Previous explosions have produced hazardous conditions primarily near the summit crater, but occasionally they have been large enough to produce a drifting ash cloud.
Cleveland volcano is monitored by only two seismic stations, which restricts AVO's ability to detect precursory unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption may be possible using a combination of seismic, infrasound, lightning, and satellite data.
Cleveland volcano forms the western portion of Chuginadak Island, a remote and uninhabited island in the east central Aleutians. The volcano is located about 75 km (45 mi) west of the community of Nikolski, and 1500 km (940 mi) southwest of Anchorage. The most recent significant period of eruption began in February, 2001 and produced 3 explosive events that generated ash clouds as high as 39,000 ft above sea level. The 2001 eruption also produced a lava flow and hot avalanche that reached the sea. Since then, Cleveland has been intermittently active producing small lava flows, often followed by explosions that generate small ash clouds generally below 20,000 ft above sea level. These explosions also launch debris onto the slopes of the cone producing hot pyroclastic avalanches and lahars that sometimes reach the coastline.
OTHER ALASKA VOLCANOES
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Michelle Coombs, Scientist-in-Charge, USGS
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Jessica Larsen, Acting Coordinating Scientist, UAF
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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.