Catalog of Earthquake Hypocenters at Alaskan Volcanoes: January 1 through December 31, 2002

The Alaska Volcano Observatory (AVO), a cooperative program of the U.S.
Geological Survey, the Geophysical Institute of the University of Alaska
Fairbanks, and the Alaska Division of Geological and Geophysical Surveys, has
maintained seismic monitoring networks at historically active volcanoes in
Alaska since 1988 (Power and others, 1993; Jolly and others, 1996; Jolly and
others, 2001; Dixon and others, 2002). The primary objectives of this program
are the seismic monitoring of active, potentially hazardous, Alaskan volcanoes
and the investigation of seismic processes associated with active volcanism.
This catalog presents the basic seismic data and changes in the seismic
monitoring program for the period January 1, 2002 through December 31, 2002.
Appendix G contains a list of publications pertaining to seismicity of Alaskan
volcanoes based on these and previously recorded data. The AVO seismic network
was used to monitor twenty-four volcanoes in real time in 2002. These include
Mount Wrangell, Mount Spurr, Redoubt Volcano, Iliamna Volcano, Augustine
Volcano, Katmai Volcanic Group (Snowy Mountain, Mount Griggs, Mount Katmai,
Novarupta, Trident Volcano, Mount Mageik, Mount Martin), Aniakchak Crater,
Mount Veniaminof, Pavlof Volcano, Mount Dutton, Isanotski Peaks, Shishaldin
Volcano, Fisher Caldera, Westdahl Peak, Akutan Peak, Makushin Volcano, Great
Sitkin Volcano, and Kanaga Volcano (Figure 1). Monitoring highlights in 2002
include an earthquake swarm at Great Sitkin Volcano in May-June; an earthquake
swarm near Snowy Mountain in July-September; low frequency (1-3 Hz) tremor and
long-period events at Mount Veniaminof in September-October and in December;
and continuing volcanogenic seismic swarms at Shishaldin Volcano throughout the
year. Instrumentation and data acquisition highlights in 2002 were the
installation of a subnetwork on Okmok Volcano, the establishment of telemetry
for the Mount Veniaminof subnetwork, and the change in the data acquisition
system to an EARTHWORM detection system. AVO located 7430 earthquakes during
2002 in the vicinity of the monitored volcanoes. This catalog includes: (1) a
description of instruments deployed in the field and their locations; (2) a
description of earthquake detection, recording, analysis, and data archival
systems; (3) a description of velocity models used for earthquake locations;
(4) a summary of earthquakes located in 2002; and (5) an accompanying UNIX
tar-file with a summary of earthquake origin times, hypocenters, magnitudes,
and location quality statistics; daily station usage statistics; and all
HYPOELLIPSE files used to determine the earthquake locations in 2002.

[Summary provided by the USGS.]