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Alaska Volcano Observatory
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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).
Color Code YELLOW / Alert Level ADVISORYvolcano image
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Color Code ORANGE / Alert Level WATCHvolcano image
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Color Code ORANGE / Alert Level WATCHvolcano image
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Color Code YELLOW / Alert Level ADVISORYvolcano image
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New publication: Alaska Volcano Observatory geochemical database, version 2
Posted: July 26, 2019

K Wallace selecting Akutan tephras for analysis
The first release of the Alaska Volcano Observatory Geochemical Database (Cameron and others, 2014), included station and sample metadata for published Quaternary volcanic samples in Alaska and their whole-rock analytical values. Version 2 adds separate categories of data for tephra glass and groundmass glass analyses. Tephra (in this dataset, generally volcanic ash, although the definition of tephra includes all pyroclastic material) deposits can be preserved in the geologic record at both proximal and distal locations, with the deposit thickness and area dictated by the eruption size and wind directions at the time of eruption. As markers of previous explosive activity, tephra deposits provide a crucial record of prehistoric and modern eruptions. Correlating tephra deposits across Alaska and the northern hemisphere requires an understanding of their age, chemistry, and character. Such information has been reported in publications spanning numerous research disciplines over the past decades. Tephra data in particular are a key component in understanding the process, magnitude, and frequency of volcanic eruptions, and improve ashfall hazard assessments and ashfall modeling efforts. In addition, tephrostratigraphy is an integral part of linking marine, lacustrine, and terrestrial records critical to paleoclimate and archaeological research. The compilation and storage of tephra metadata and analytical data is a joint effort between the Alaska Volcano Observatory (AVO) staff at the Alaska Division of Geological & Geophysical Surveys (DGGS) and the U.S. Geological Survey Alaska Tephra Laboratory (USGS ATL).

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U.S. Geological Survey
Saturday, August 17, 2019, 1:27 PM AKDT (Saturday, August 17, 2019, 21:27 UTC)

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 seismic tremor continues. Elevated surface temperatures were observed in satellite views over the past day. No unusual activity was observed in web-camera views.

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

51°55'44" N 179°35'52" E, Summit Elevation 2625 ft (800 m)
Current Volcano Alert Level: WATCH
Current Aviation Color Code: ORANGE

There was a significant increase in the intensity of seismic tremor for several hours yesterday afternoon. Tremors became intermittent and has since diminished to low levels. No activity observed in satellite data. It remains possible for unrest to escalate rapidly with little to no warning.

Semisopochnoi is monitored with an on-island seismic network and remotely by satellite and lightning sensors. An infrasound array on Adak Island may detect explosive emissions from Semisopochnoi with a slight delay (approximately 13 minutes) if atmospheric conditions permit.

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

Seismic unrest continues with occasional low-frequency earthquakes. Barely elevated surface temperatures observed in occasional clear satellite views. No unusual activity observed in web camera views over the past day.

Veniaminof volcano is monitored with a local real-time seismic network, which will typically allow AVO to detect changes in unrest that may lead to a more significant explosive eruption. AVO combines seismic, infrasound, lightning, and satellite data for rapid detection of such events.

52°49'20" N 169°56'42" W, Summit Elevation 5676 ft (1730 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW

Elevated surface temperatures observed in satellite images over the past day. Seismicity has decreased slightly in the past 24 hours. No activity was detected in regional or local infrasound data.

Episodes of lava effusion and explosions can 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, unavailable since January 26, 2019, have been restored to full functionality and are now part of the routine monitoring data stream for Cleveland volcano.


Information on all Alaska volcanoes is available at : http://www.avo.alaska.edu.

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

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Peter Cervelli, Acting Scientist-in-Charge, USGS
pcervelli@usgs.gov (907) 786-7497

Janet Schaefer, Acting Coordinating Scientist, DGGS
janet.schaefer@alaska.gov (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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URL: www.avo.alaska.edu/index.php
Page modified: March 19, 2018 16:09
Contact Information: AVO Web Team

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