ALASKA VOLCANO OBSERVATORY WEEKLY UPDATE
U.S. Geological Survey
Friday, May 18, 2018, 10:51 AM AKDT (Friday, May 18, 2018, 18:51 UTC)

CLEVELAND VOLCANO (VNUM #311240)
52°49'20" N 169°56'42" W, Summit Elevation 5676 ft (1730 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW

Low-level unrest continues at Cleveland Volcano. No explosions have been observed at the volcano in the past week. A low altitude steam plume was observed emanating from the summit of Cleveland Volcano in satellite data from Monday and weak to moderate elevated surface temperatures were observed in satellite data on Tuesday and Thursday. These observations are consistent with an open degassing vent. Data streams from the seismic and pressure sensor stations on Cleveland stopped being received at AVO a little after 2:00 PM on Monday, May 14 due to a power outage in Nikolski. Efforts are ongoing to restore the network. A large explosion from Cleveland, should it occur, would be detected on other pressure sensor and seismic networks in the region but precursory seismicity and smaller explosions may go undetected.

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.

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

Information on all Alaska volcanoes is available at : http://www.avo.alaska.edu.

For definitions of Aviation Color Codes and Volcano Alert Levels, see: http://www.avo.alaska.edu/color_codes.php

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CONTACT INFORMATION:

Chris Waythomas, Acting Scientist-in-Charge, USGS
cwaythomas@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAF
jflarsen@alaska.edu (907) 322-4085

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.

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