AVO monitors seismic activity at potentially active volcanoes across Alaska and calculates locations and magnitudes for earthquakes (typically magnitude 3.0 and below) near the 32 active volcanoes where AVO operates seismic networks.

A geophysicist reviews each location and magnitude before it is released, therefore AVO’s locations may not be available for up to 2 or 3 days after the event, although larger earthquakes can be processed sooner.

Other organizations such as the Alaska Earthquake Center (AEC) at the University of Alaska Fairbanks Geophysical Institute (UAF/GI) and the USGS National Earthquake Information Center (NEIC) also locate the larger (magnitude >2.5) earthquakes.Because each organization uses slightly different techniques to calculate locations and magnitudes, the initial published locations and magnitudes may differ slightly for the same earthquake. The Advanced National Seismic System (ANSS) coordinates earthquake information from these organizations and keeps the Comprehensive Earthquake Catalog, a publicly available archive with detailed and complete information on all located earthquakes nation-wide: earthquake.usgs.gov/data/comcat/