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Earthquake Probabilities and Hazards in the U.S. Pacific Northwest

Fact Sheet 2025-3050
By: , , , , , , and 
https://doi.org/10.3133/fs20253050

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Abstract

Earthquakes and their cascading consequences pose a significant threat to the people, environment, infrastructure, and economy of the U.S. Pacific Northwest. The Pacific Northwest is susceptible to three types of earthquakes: deep (intraslab) earthquakes, subduction zone (megathrust) earthquakes, and shallow crustal earthquakes. For each of these earthquake types, earth scientists can use a variety of methods to estimate the probability of occurrence for future events, which constrains seismic hazard and informs building codes. The timing of past earthquakes indicates that there is an 85-percent chance of a magnitude 6.5 or greater deep earthquake in the Puget Sound region; a 10-15-percent chance of an approximately magnitude 9 earthquake on the Cascadia Subduction Zone; and a 17-percent chance of a magnitude 6.5 or greater crustal fault earthquake in the Puget Sound region in the next 50 years. Individuals and communities can take simple steps to prepare for and reduce the impact of future earthquakes.

Plain Language Summary

Earthquakes and their cascading consequences pose a significant threat to the people, environment, infrastructure, and economy of the U.S. Pacific Northwest. The timing of previous earthquakes helps estimate the likelihood of future events.

Suggested Citation

Wirth, E., Frankel, A., Sherrod, B., Grant, A., Dunham, A., Stone, I., and Grossman, J., 2025, Earthquake probabilities and hazards in the U.S. Pacific Northwest (ver. 1.1, September 30, 2025): U.S. Geological Survey Fact Sheet 2025–3050, 6 p., https://doi.org/10.3133/fs20253050.

ISSN: 2327-6932 (online)

ISSN: 2327-6916 (print)

Study Area

Table of Contents

  • Plain Language Summary
  • Earthquakes in the U.S. Pacific Northwest
  • Determining the Likelihood of Future Earthquakes
  • Deep (Intraslab) Earthquakes
  • Subduction Zone (Megathrust) Earthquakes
  • Crustal Earthquakes
  • Other Seismic Signals and Phenomena
  • Preparing for Future Earthquakes
  • Acknowledgments
  • Selected References
Publication type Report
Publication Subtype USGS Numbered Series
Title Earthquake probabilities and hazards in the U.S. Pacific Northwest
Series title Fact Sheet
Series number 2025-3050
DOI 10.3133/fs20253050
Edition Version 1.0: September 19, 2025; Version 1.1: September 30, 2025
Publication Date September 19, 2025
Year Published 2025
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Earthquake Science Center
Description 6 p.
Country United States
State California, Oregon, Washington
Online Only (Y/N) N
Additional Online Files (Y/N) N
Additional publication details