Alaska-Aleutian Subduction Zone Studies

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Exploring Seismic and Aseismic Slip in the Alaska-Aleutian Arc

Tectonic tremor, a weak vibration of the ground detectable only through sensitive seismometers, has been identified throughout south-central Alaska. This research uses the catalog of detected tremor to provide key constraints on fault conditions, plate boundary geometry and the relationship between tremor and slow slip. We investigate the spatial and temporal characteristics of tectonic tremor and slow slip phenomena in Alaska’s diverse tectonic environments, and relate it to earthquakes and slow slip in order to elucidate factors controlling tremor and complement similar studies in the contiguous United States.

Alaska-Aleutian Paleoseismology and Paleotsunami Studies

This research quantifies the timing, location, and size of large prehistoric earthquakes on upper-plate and plate-boundary faults, and the tsunamis that may accompany them, between Prince William Sound and the western Aleutians. We assess these parameters through comprehensive paleoseismology and paleotsunami studies at sites on the south-facing coasts of the Aleutian, Kodiak and Semidi Islands and the Patton Bay fault system in Prince William Sound. Fieldwork involves USGS scientists and academic collaborators. We develop histories of past earthquakes and tsunamis through extensive stratigraphic and geomorphic field studies, paleontologic analyses, tephrachronology, and radiometric dating. The paleoseismic and paleotsunami data we gather in the field ultimately contributes to the assessment of earthquake and tsunami hazards throughout western North America, including USGS National Seismic Hazard Maps and tsunami inundation maps developed through NOAA’s National Tsunami Hazard Mitigation Program.