The Alaska Volcano Observatory (AVO) is responsible for monitoring the more than 40 historically active volcanoes of the Aleutian arc. As of December 31, 2004, 27 of these volcanoes are instrumented with seismometers to track earthquake activity, and AVO seismologists have defined a background level of activity for each of these volcanoes. AVO’s routine monitoring program also includes daily analysis of satellite imagery, occasional observational overflights, and compilation of pilot reports and observations of local residents and mariners. Additionally, AVO receives real-time deformation information from permanent Global Positioning System (GPS) stations at four Alaskan volcanoes (Okmok, Augustine, Akutan, and Mount Spurr).
2004 began quietly in Alaska, continuing a trend of little volcanic unrest that has persisted for several years. On January 9, AVO announced the beginning of formal seismic monitoring of Okmok Volcano following an extended period of calibration and improvement of the seismic network installed initially in 2002-2003. Gareloi and Tanaga volcanoes in the western Aleutians were added to the list of seismically monitored volcanoes in early June following determination of background seismicity. During the remainder of the year, AVO responded to volcanic unrest at three volcanoes in AlaskaMount Spurr, Veniaminof, and Shishaldin.
As part of a formal agreement between AVO and several scientific institutes in Petropavlovsk-Kamchatsky, Russia, AVO is responsible for disseminating information on behalf of the Kamchatkan Volcanic Eruption Response Team (KVERT). Additionally, a newly established eruption response team, tracking activity in the Kurile Islands of the Russian Far East, is also in the beginning stages of collaborative work with AVO and KVERT to develop warning communication protocols. In 2004, AVO assisted in broadcasting alerts about activity at five Russian volcanoesSheveluch, Klyuchevskoy, Bezymianny, and Karymsky of the Kamchatka Peninsula, and Chirinkotan in the Kuriles.