Shishaldin Volcano


June 22, 2020: Since the January post below, Shishaldin’s activity has lessened and it has been at Yellow or Orange status, currently at Yellow since mid-April.


Am bumping this update because AVO just raised the aviation code to Red – Shishaldin might be having a major event. The above is a file image. I don’t know that there are any current images, given the winter weather there; you can check for updates here. There are links to webcams at this page, but one is covered with snow and the other is dark and has had no images posted today, per the information on that page.

AVO did tweet this about an hour ago:



And here is a January 6th image of the ongoing lava flow:


A. Merculief/AVO


Sigh. That is one spectacular volcano, in a remote area (per this local news report, the cloud isn’t seen to be a threat to airliners or to local people at the moment), and it would be wonderful to see it in full eruption.


Original post from December 15, 2019, with an update from last Friday:

January 3, 2020, 9:27 p.m. Pacific: A large blast from Shishaldin today! Fortunately, just the one. Unfortunately, there don’t seem to be any images: that’s an effect of winter in Alaska, I guess.

ALASKA VOLCANO OBSERVATORY WEEKLY UPDATE
U.S. Geological Survey
Friday, January 3, 2020, 2:58 PM AKST (Friday, January 3, 2020, 23:58 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

The eruption of Shishaldin Volcano that began in late July, 2019 continues with short duration explosive activity from the summit crater and effusion of lava flows on the upper flanks of the volcano. This morning, beginning about 9:30 AKST, seismicity at the volcano began increasing over a period of several hours and eventually led to a brief period of sustained ash emission resulting in an ash cloud that reached as high as 27,000 feet above sea level according to reports from passing pilots. The ash cloud consisted of a linear, directed ash plume that extended from the volcano to the southeast at least 75 miles. The ash cloud also produced minor amounts of volcanic lightning. Seismicity has abruptly decreased and for now there appears to be no sign of continued ash emission. Satellite images of the volcano obtained throughout the week showed consistently elevated surface temperatures indicating continued effusion of lava.

Thus far, the 2019 eruption has produced lava flows, pyroclastic flows, lahars (mudflows), and minor ash fallout on the flanks of the volcano. For most of the current eruption, ash emissions have been restricted to the immediate vicinity of the volcano and altitudes of less than 15,000 ft. asl, until today when an ash cloud reached as high as 27,000 ft. asl. During this heightened level of activity more powerful explosions could occur with little warning and produce higher ash clouds that may pose a hazard to aircraft. . .


Original post:

It’s rare to see such good views of this cloud-wrapped but spectacular volcano:



And yet Shishaldin has been quite active since it came back to life in late July 2019, after only resting for a couple of years. This week, it has been tantruming a bit.

Per the Alaska Volcano Observatory:

ALASKA VOLCANO OBSERVATORY WEEKLY UPDATE
U.S. Geological Survey
Friday, December 13, 2019, 11:33 AM AKST (Friday, December 13, 2019, 20:33 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

The eruption of Shishaldin volcano that began in late July continues. Eruption activity at the volcano intensified yesterday with the possible collapse of the summit spatter cone and lava flows on the north and northwest flanks. This event produced a small ash cloud to 25,000 feet above sea level that drifted to the northwest and dissipated within a couple of hours. Highly elevated surface temperatures were observed in satellite data from today. Web camera images show a robust steam plume form the summit and incandescence in night-time images. Seismicity at the volcano remains elevated.

Thus far, the 2019 eruption has produced lava flows, pyroclastic flows, and lahars (mudflows) on the flanks of the volcano. For most of the current eruption, ash emissions have been restricted to the immediate vicinity of the volcano and altitudes of less than 12,000 ft. asl. During this heightened level of activity more powerful explosions such as the one that occurred yesterday could occur with little warning and produce higher ash clouds that may pose a hazard to aircraft.

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

Shishaldin volcano, located near the center of Unimak Island in the eastern Aleutian Islands, is a spectacular symmetric cone with a base diameter of approximately 16 km (10 mi). A 200-m-wide (660 ft) funnel-shaped summit crater typically emits a steam plume and occasional small amounts of ash. Shishaldin is one of the most active volcanoes in the Aleutian volcanic arc, with at least 54 episodes of unrest including over 24 confirmed eruptions since 1775. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft above sea level.


Shishaldin, December 12, 2019, around 8:30 p.m., local time. (Image: Aaron Merculief/AVO)


Here is the AVO’s Shishaldin portal. (Of note, AVO is the only US volcano observatory, as far as I know, with an individual Twitter feed.)

And here is more information on Shishaldin from the Global Volcanism Program.


Featured image: Ben Lagasse/AVO



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