New!"Putting Down Roots in Earthquake Country: Your Handbook for Earthquakes in Idaho" [Download pdf]
Geological and seismological studies show that earthquakes are likely to happen in any of several active zones in Idaho and adjacent states. Idaho has experienced two large earthquakes in historical times—the 1959 HebgenLake earthquake (M7.3) and the 1983 Borah Peak earthquake (M6.9). Both tremors caused fatalities and millions of dollars in damage.
In all parts of Idaho, the historical record of seismicity reveals at least a moderate threat from earthquakes. The Idaho Geological Survey addresses earthquake concerns by studying faults and seismic activity, and by promoting earthquake education programs. The Survey works closely with other agencies such as the Idaho Bureau of Homeland Security in planning state and regional earthquake policy and response, and participates in regional organizations such as the Western States Seismic Policy Council (WSSPC).
Location map and descriptions of historical earthquakes in Idaho and an isoseismal map for the 1983 Borah Peak earthquake. GeoNote 5 describes the Borah Peak earthquake.