ALASKA VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Sunday, August 12, 2018, 1:12 PM AKDT (Sunday, August 12, 2018, 21:12 UTC)

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

Unrest continues at Cleveland volcano. No activity was observed over the past day in cloudy satellite images. Web camera views were also obscured by clouds. Nothing significant was detected in seismic or pressure sensor (infrasound) data during the last 24 hours.

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.

GREAT SITKIN VOLCANO (VNUM #311120)
52°4'35" N 176°6'39" W, Summit Elevation 5709 ft (1740 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW

Low-level unrest continues at Great Sitkin Volcano. In the past day, a small phreatic explosion was observed in seismic data at 11:05 am AKDT on August 11 (19:05 UTC). Small local earthquakes preceded the event and stopped following the phreatic explosion. The event is similar to 3 other phreatic explosions that have occurred over the past 2 years at Great Sitkin, most recently on June 10, 2018. A small ash deposit near the summit was observed in clear satellite images after the June 10 event. Nothing significant was observed in cloudy satellite images during the last 24 hours.

Great Sitkin Volcano is monitored with a local real-time seismic network, which will typically allow AVO to detect changes in unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption would be accomplished using a combination of seismic, infrasound, lightning, and satellite data.

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

SUBSCRIBE TO VOLCANO ALERT MESSAGES by email: http://volcanoes.usgs.gov/vns/

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CONTACT INFORMATION:

John Paskievitch, Acting Scientist-in-Charge, USGS
jpaskie@usgs.gov (907) 786-7497

Cheryl Cameron, Acting Coordinating Scientist, DGGS
cheryl.cameron@alaska.gov (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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