ALASKA VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Thursday, October 24, 2019, 12:07 PM AKDT (Thursday, October 24, 2019, 20:07 UTC)
SHISHALDIN VOLCANO
(VNUM #311360)
54°45'19" N 163°58'16" W,
Summit Elevation 9373 ft (2857 m)
Current Volcano Alert Level: WATCH
Current Aviation Color Code:
ORANGE
Satellite data from the past day show that lava now fills the summit crater and is beginning to flow over the northern crater rim in two locations. One 200 m (600 ft) long lava flow has melted snow and produced a large ~2.9 km (~1.8 mile) long lahar extending down the north flank reaching ~1230 m (~4000 ft) elevation and a smaller lava flow has caused a ~1 km (~0.6 mile) long lahar down the northeast flank. Spatter from low-level explosive activity is accumulating around the crater rim and melting snow, as well. This activity has coincided with strongly elevated surface temperatures, elevated seismicity, and infrasound detections. There has been no evidence of any significant ash-bearing volcanic plumes over the past day in cloudy satellite imagery and web camera views.
Shishaldin is monitored by local seismic and infrasound sensors, satellite data, a web camera, a telemetered geodetic network, and distant infrasound and lightning networks.
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
No activity was observed on the local seismic stations at Cleveland and no eruptive activity was detected in regional infrasound data over the past day. No activity was observed in cloudy satellite data over the past day but a small steam plume was seen in web camera images this morning.
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.
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.
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
Low-level seismic activity was observed on the local seismic network at Semisopochnoi over the past day. No eruptive activity has been observed on infrasound stations. Cloudy weather conditions continue to obscure satellite images of the island.
Semisopochnoi is monitored with an on-island seismic network and remotely by satellite and lightning sensors. An infrasound array on Adak Island may detect explosive emissions from Semisopochnoi with a slight delay (approximately 13 minutes) if atmospheric conditions permit.
PAVLOF VOLCANO
(VNUM #312030)
55°25'2" N 161°53'37" W,
Summit Elevation 8261 ft (2518 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code:
YELLOW
No new activity at Pavlof has been observed in seismic or infrasound data since the events on October 19. No activity was seen in cloudy satellite images and web camera views over the past day.
The level of unrest at Pavlof can change quickly and the progression to eruptive activity can occur with little or no warning. We continue to monitor Pavlof closely and will provide any new information about the status of the volcano when or if it becomes available.
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
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.