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The Alaska Volcano Observatory (AVO) is a joint program of the United States Geological Survey (USGS), the Geophysical Institute of the University of Alaska Fairbanks (UAFGI), and the State of Alaska Division of Geological and Geophysical Surveys (ADGGS).
RESTLESS VOLCANOES
Cleveland
Color Code YELLOW / Alert Level ADVISORYvolcano image
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Shishaldin
Color Code YELLOW / Alert Level ADVISORYvolcano image
Full details ...

January 30, 2016 Fieldwork at Iliama and Spurr
Posted: February 12, 2016

Helena at SSN

Not all fieldwork stops for winter! On January 30, 2016, AVO and EarthScope Transportable Array personnel had a great day of Cook Inlet fieldwork at Spurr and Iliamna - our seismic data for these volcanoes is much improved. Here are some photos from the day of fieldwork.



preparing to dig




Station CKT at Spurr




Repeater ILCB
New publication highlights the importance of ash scrubbing in the evaluation of hazards from explosive eruptions
Posted: January 13, 2016

Phreatomagmatic eruption at Okmok, 3 Aug 2006

Okmok volcano, located on Umnak Island in the eastern Aleutian Islands, Alaska, erupted explosively in July-August 2008 from vents within its 2050-year-old caldera. Water-magma interaction was an important process in the 2008 Okmok eruption, causing efficient fragmentation that produced large amounts of fine ash throughout the five weeks. This paper describes the stratigraphy, distribution, and grain size, shape, and composition characteristics of the deposits of the 2008 Okmok eruption. Understanding the production and deposition of fine ash in the 2008 Okmok eruption is important for hazard assessment during similar eruptions in Alaska and for the development of a better understanding of phreatomagmatism and violent mafic eruptions.
Unema, J.A., Ort, M.H., Larsen, J.F., Neal, C.A., and Schaefer, J.R., 2016, Water-magma interaction and plume processes in the 2008 Okmok eruption, Alaska: GSA Bulletin, 15 p., doi:10.1130/B31360., abstract available here.

LAST ACTIVITY REPORT
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ALASKA VOLCANO OBSERVATORY WEEKLY UPDATE
Friday, February 12, 2016 11:01 AM AKST (Friday, February 12, 2016 20:01 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

The level of seismic activity has changed little over the past week and remains above background levels. The ongoing seismic activity is characterized by low-level seismic tremor, small discrete events, and very small explosions. No activity was observed in mostly cloudy satellite images this week and for a brief period yesterday afternoon, a small steam plume was evident at the summit in web camera views of the volcano.

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.

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

Nothing noteworthy observed in mostly cloudy satellite images during the past week. No unusual seismic activity was detected this week.

Cleveland volcano forms the western portion of Chuginadak Island, a remote and uninhabited island in the east central Aleutians. The volcano is located about 75 km (45 mi) west of the community of Nikolski, and 1500 km (940 mi) southwest of Anchorage. The most recent significant period of eruption began in February, 2001 and produced 3 explosive events that generated ash clouds as high as 39,000 ft above sea level. The 2001 eruption also produced a lava flow and hot avalanche that reached the sea. Since then, Cleveland has been intermittently active producing small lava flows, often followed by explosions that generate small ash clouds generally below 20,000 ft above sea level. These explosions also launch debris onto the slopes of the cone producing hot pyroclastic avalanches and lahars that sometimes reach the coastline.

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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RUSSIAN VOLCANO INFORMATION

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Page modified: November 15, 2014 16:35
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