ALASKA VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Tuesday, June 16, 2020, 12:46 PM AKDT (Tuesday, June 16, 2020, 20:46 UTC)

MAKUSHIN VOLCANO (VNUM #311310)
53°53'24" N 166°55'30" W, Summit Elevation 5906 ft (1800 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW

Vigorous earthquake activity at Makushin Volcano began yesterday afternoon (June 15, 2020) and may be associated with volcanic unrest. As a result the Aviation Color Code and Volcano Alert Level was increased to YELLOW/ADVISORY. Two earthquakes in excess of M4.0 and one in excess of M3.0 have occurred and were located about 11 km (6.8 miles) SE of the summit at a depth of about 8 km (5 miles). These earthquakes were felt in the community of Unalaska (located about 14 km or 8.6 miles away from the epicenters). Numerous smaller quakes have also been detected but most are too small to be felt by residents in Unalaska. The volcano is monitored with a network of seismic and GPS instruments, a web camera, satellite data, and regional infrasound and lightning detection instruments. There has been no surficial activity detected or observed in other monitoring data.

It is unclear at this time whether this seismic activity will result in an eruption. The main hazard from an eruption of Makushin would likely be from airborne ash and ash fall. Wind trajectory plots and hypothetical ash fall model information is available at https://www.avo.alaska.edu/activity/Makushin.php These models are updated twice per day in a hypothetical mode and would be update immediately if there was an eruption. Seismic data, web camera images and information products are also available at this site.

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 likely continues at Cleveland. No activity was seen in cloudy satellite views or detected on regional geophysical networks. The local geophysical stations and web camera at Cleveland are currently unavailable due to an ongoing network outage.

Episodes of lava effusion and explosions can occur without advance warning. Explosions from Cleveland are normally short duration and only present a hazard to aviation in the immediate vicinity of the volcano. Larger explosions that present a more widespread hazard to aviation are possible, but are less likely and occur less frequently.

When the network is operational, 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.

SHISHALDIN VOLCANO (VNUM #311360)
54°45'19" N 163°58'16" W, Summit Elevation 9373 ft (2857 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW

Low-level unrest continues at Shishaldin. Seismicity remains above background over the past day. No eruptive activity was seen in cloudy satellite images and web camera images were obscured by clouds. No explosive activity was detected by regional infrasound sensors.

Although unrest is currently at low levels, conditions could change rapidly with minimal warning, and eruptive activity in the summit crater could resume. If eruptive activity does resume, lava flows, lahars, and ash-producing events could occur.

Shishaldin is monitored by local seismic and infrasound sensors, satellite data, web cameras, a telemetered geodetic network, and distant infrasound and lightning networks.

SEMISOPOCHNOI VOLCANO (VNUM #311060)
51°55'44" N 179°35'52" E, Summit Elevation 2625 ft (800 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW

Unrest continues at Semisopochnoi. Seismic tremor continues, mostly at low levels but with short, energetic bursts recorded intermittently. Satellite observations were mostly obscured by low clouds but no activity observed.

Semisopochnoi is monitored by local seismic sensors, satellite data, and lightning detection networks. An infrasound array on Adak Island may detect explosive emissions from Semisopochnoi with a slight delay (approximately 13 minutes) if atmospheric conditions permit.

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

Unrest continues at Great Sitkin. A few small local earthquakes have occurred over the past day. No explosive activity was detected by regional infrasound sensors. Satellite and web camera images were obscured by clouds.

Great Sitkin volcano is monitored by local seismic and infrasound sensors, satellite data, web cameras, and remote infrasound and lightning networks.

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:

Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@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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