USGS updates National Seismic Hazard Maps

Sixteen states deemed ‘high risk’ in latest revision

July 30, 2014 |
Illustration: USGS

The U.S. Geological Service recently released an update of U.S. National Seismic Hazard Maps that reflect the latest analysis of where future earthquakes will occur, how frequently they may occur, and their strength.

While all states have some potential for earthquakes, 42 of the 50 states have a reasonable chance of experiencing damaging ground shaking from an earthquake in the next 50 years. Sixteen states have a relatively high likelihood of experiencing damaging ground shaking. These states have historically experienced earthquakes with a magnitude 6 or greater. The hazard is especially high along the west coast, intermountain west, and in several active regions elsewhere such as near New Madrid, Mo., and near Charleston, S.C.

The eastern U.S. has the potential for larger and more damaging earthquakes than considered in previous maps and assessments. This finding is due to what scientists learned following the magnitude 5.8 earthquakes that struck Virginia in 2011. It was among the largest earthquakes to occur along the east coast in the last century, and indicated that even larger events in the region are possible.

The maps are used in risk analyses calculated using factors such as population levels, building exposure, and building construction practices. These assessments are used for establishing building codes, in the analysis of seismic risk for key structures, and in determining insurance rates. They can also aid emergency preparedness plans, and private property decisions such as re-evaluating one’s real estate and making it more resilient.


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