Evaluation of slip history and Holocene activity on faults in the Strawberry Mountains

  • 26 Oct 2021
  • 7:00 PM
  • Zoom Presentation

Andrew Dunning

Portland State University


Watch the recorded presentation



In 2018, state geologists discovered active faults in the Strawberry Mountains of Grant County. These previously undocumented faults are unexpected based on what we currently know about plate tectonics in Oregon. Furthermore, lack of seismic research in Eastern Oregon as a whole has led the USGS to qualify much of Oregon as a “Low” seismic hazard zone. The discovery of recently active faults in this area will lead to a reevaluation of that distinction in time, but first we need to know when the last earthquake was and how often they likely occur.

In this talk, Andrew Dunning will present preliminary results from ongoing research and analysis of the recently-discovered Strawberry Fault. Using sediments on top of the fault and glacial deposits coming down from the mountains, Andrew is looking for clues about past behavior of the fault. His research is mostly focused on finding the age of the most recent earthquake, but it also includes a study of Last Glacial Maximum-age glacial deposits to peer deeper into the fault’s history.

Central Oregon Geoscience Society

Email: COGeoSoc@gmail.com
P.O. Box 2154,  Bend, Oregon 97709

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