ALASKA VOLCANO OBSERVATORY DAILY UPDATE U.S. Geological Survey Wednesday, July 17, 2019, 11:27 AM AKDT (Wednesday, July 17, 2019, 19:27 UTC)
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
Some seismic tremor has continued over the last 24 hours. No eruptive activity was detected in infrasound data and and cloudy conditions obscured satellite and web camera views of the volcano.
Shishaldin is monitored by local seismic and infrasound sensors, satellite data, a web camera, 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
Local seismic sensors and regional infrasound sensors detected a signal yesterday likely generated by a small explosion from Semisopochnoi. No significant ash emissions are expected from events of this size, and no ash signals have been observed in cloudy satellite images. Seismic tremor, fluctuating between periods of continuous activity and discrete bursts, continued over the last 24 hours.
Semisopochnoi is monitored with an on-island seismic network and remotely by satellite and lightning sensors. Furthermore, an infrasound array on Adak Island may detect explosive emissions from Semisopochnoi with a 13 minute delay if atmospheric conditions permit.
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
Weakly elevated surface temperatures were observed at the summit of the volcano in partly cloudy satellite views over the last 24 hours. No activity was detected in regional seismic or infrasound data.
Additional episodes of lava effusion and explosions are likely and will 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.
Local seismic and infrasound data at Cleveland have been unavailable since January 26, 2019. This restricts AVO's ability to rapidly detect an explosive eruption. AVO is able to monitor the volcano for signs of eruptive activity with satellite, lightning, and regional seismic and infrasound data.
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.