ALASKA VOLCANO OBSERVATORY WEEKLY UPDATE
U.S. Geological Survey
Friday, October 17, 2014, 1:42 PM AKDT (Friday, October 17, 2014, 21:42 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

Low-level eruptive activity likely continues at Shishaldin. Elevated surface temperatures were detected in satellite data throughout the week when views were clear. Sound waves coupling into the ground (ground-coupled air waves) from small explosions were detected early in the week in seismic data but have since diminished. Low levels of tremor activity were detected in seismic data throughout the week.

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.

KATMAI VOLCANO (VNUM #312170)
58°16'44" N 154°57'12" W, Summit Elevation 6716 ft (2047 m)
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN

Strong winds in the Katmai area picked up loose 1912 volcanic ash and carried it east over Kodiak Island on Tuesday this week (10/14/14). AVO detected a cloud of resuspended ash blowing from the vicinity of Katmai and the Valley of Ten Thousand Smokes toward Kodiak Island. The National Weather Service estimated the top of the plume at 4,000 feet (1,219 m) above sea level. AVO received a report of hazy conditions and trace ash fall (less than 1/32 inch) at Karluk on the southwest side of Kodiak island. FAA web camera images in Karluk showed hazy conditions.

This phenomenon is not the result of volcanic activity and occurs seasonally in the spring and fall during times of high winds, and dry, snow-free conditions in the Katmai area and other young volcanic areas of Alaska. No eruption is in progress. All of the volcanoes of the Katmai area (Snowy, Griggs, Katmai, Novarupta, Trident, Mageik, Martin) remain at color code GREEN.

Resuspended volcanic ash should be considered hazardous and could be damaging to aircraft and health. For more information on volcanic ash and human health, visit the following website: http://volcanoes.usgs.gov/ash/.

OTHER ALASKA VOLCANOES

Other Alaska volcanoes show no signs of significant unrest: http://www.avo.alaska.edu/activity/

AVO scientists conduct daily checks of earthquake activity at all seismically-monitored volcanoes, examine web camera and satellite images for evidence of airborne ash and elevated surface temperatures, and consult other monitoring data as needed.

For definitions of Aviation Color Codes and Volcano Alert Levels, see: http://www.avo.alaska.edu/color_codes.php

FOR MORE INFORMATION ON ALASKA VOLCANOES: http://www.avo.alaska.edu

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

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CONTACT INFORMATION:

John Power, Scientist-in-Charge, USGS
jpower@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jeff.freymueller@gi.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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