Earthquakes in Idaho
Idaho is among the most active of states in terms of the number of earthquakes experienced each year. Hundreds of small earthquakes have been
recorded in the state by seismographs since systematic observations began in the mid-20th century. Two of the largest historic earthquakes in the
continental US occurred in Idaho or within a few miles of the Idaho border in 1983 and 1959. These powerful magnitude 6.9 and 7.3 events caused
fatalities as well as destroying buildings, roads, and other structures. The accounts of 19th century Euro-American settlers in Idaho also contain
descriptions of damaging earthquakes. Geologists have extended the Idaho earthquake record thousands of years into the past by excavating faults and
determining the age and size of major prehistoric quakes. These lines of evidence show that damaging earthquakes occur in Idaho and may again at any
time in the future.
Putting Down Roots in Earthquake Country
The Idaho Geological Survey and IOEM have compiled a handbook for earthquakes in Idaho. This handbook includes an overview of how earthquakes affect
Idaho and can impact our livelihoods. It provides historical information on the magnitude and location of earthquakes going back to the early days of
Idaho statehood. This document also provides valuable information about how all Idahoans can prepare for, survive, and recover from these inevitable
events. There is a glossary of terms that will assist you with understanding earthquakes, how they happen and the impact they can have on you.
Download a copy of this booklet here.
A classroom activities supplement is also available.
Historical Information of Earthquakes in Idaho
The 1983 Borah Peak Earthquake was the largest recorded earthquake in Idaho, and one of the largest in the United States. Visit the United States
Geological Survey for more information on this earthquake. Although Borah Peak was the largest earthquake in Idaho, there have been many other
memorable earthquakes in our state. The Idaho Geological Survey has compiled maps and information on these quakes and is available by visiting their
Idaho Earthquake Information by Region (Idaho Geological Survey)
The Intermountain Seismic Belt in Southeast Idaho
The Central Idaho Seismic Zone
Western Idaho Seismic Zone
North Idaho Lewis and Clark Zone
Did You Feel an Earthquake?
If you feel an earthquake, report it here and view regional maps of shaking intensity.