ALASKA VOLCANO OBSERVATORY WEEKLY UPDATE
U.S. Geological Survey
Friday, May 16, 2014, 12:24 PM AKDT (Friday, May 16, 2014, 20:24 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

Elevated surface temperatures at the summit of Shishaldin were observed in satellite data throughout the past week. Seismometers near the volcano detected periods of tremor and brief explosion signals. Web camera images over the past week occasionally showed a faint plume emanating from the summit crater. These observations are consistent with ongoing, low-level eruptive activity, mostly contained deep within the crater. An aerial view earlier this week showed minor ash on the snow and ice-covered cone.

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 10 miles (16 km). A small summit crater typically emits a noticeable steam plume with 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 at least 24 confirmed eruptions since 1775. Most of Shishaldin's eruptions have consisted of small ash and steam plumes, although a recent eruption in April-May 1999 produced an ash column that reached a height of 45,000 ft above sea level.

VENIAMINOF VOLCANO (VNUM #312070)
56°11'52" N 159°23'35" W, Summit Elevation 8225 ft (2507 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW

Seismicity remains slightly above background levels. Weakly-elevated surface temperatures were evident in satellite data when the volcano was not obscured by clouds. This likely results from cooling lava flows. Occasional clear web camera views showed a white plume drifting downwind from the summit cone.

Mount Veniaminof volcano is an andesitic stratovolcano with an ice-filled 10-km diameter summit caldera located on the Alaska Peninsula, 775 km (480 mi) southwest of Anchorage and 35 km (22 mi) north of Perryville. Veniaminof is one of the largest (~ 300 cubic km) and most active volcanic centers in the Aleutian Arc and has erupted at least 13 times in the past 200 years. Recent significant eruptions of the volcano occurred in 1993-95 and 2005. Both were Strombolian eruptions producing lava fountans and minor emissions of ash and gas from the main intracaldera cone. During the 1993-95 activity, a small lava flow was extruded into the ice field producing a melt pit. Minor ash-producing explosions occurred nearly annually between 2002 and 2008. Previous historical eruptions have produced ash plumes that reached 6,000 m (20,000 ft) above sea level (1939 and 1956) and ash fallout that blanketed areas within about 40 km (25 mi) of the volcano (1939).

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

We have seen no sign of volcanic activity at Cleveland in multiple clear satellite looks at the volcano during the past week. The last minor explosive events detected at Cleveland occurred on February 25, 2014.

Cleveland volcano forms the western half of Chuginadak Island, a remote and uninhabited island in the east central Aleutians. It is located about 75 km (45 mi) west of the community of Nikolski, and 1500 km (940 mi) southwest of Anchorage. The volcano's most recent significant eruption began in February, 2001 and it produced 3 explosive events that produced ash clouds as high as 12 km (39,000 ft) above sea level. The 2001 eruption also produced a lava flow and hot avalanche that reached the sea.

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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TELEPHONE RECORDING ON ALASKA VOLCANO STATUS (907) 786-7478

CONTACT INFORMATION:

Chris Waythomas, Acting Scientist-in-Charge, USGS
chris@usgs.gov (907) 786-7497

Pavel Izbekov, Acting Coordinating Scientist, UAFGI
pavel@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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