State high-risk on new assessment for quakesJul 18, 2014 The Associated Press
WASHINGTON -- A new federal earthquake map dials up the shaking hazard just a bit for about one-third of the United States and lowers it for one-tenth.
Wyoming is one of the highest-risk state, primarily because of the frequent seismic activity in Yellowstone National Park.
The U.S. Geological Survey on Thursday updated its national seismic hazard maps for the first time since 2008, taking into account research from the devastating 2011 earthquake and tsunami off the Japanese coast and the surprise 2011 Virginia temblor.
The maps are used for building codes and insurance purposes and they calculate just how much shaking an area probably will have in the biggest quake likely over a building's lifetime.
The highest risk places have a 2 percent chance of experiencing "very intense shaking" over a 50-year lifespan, USGS project chief Mark Petersen said. Those with lower hazard ratings would experience less intense swaying measured in gravitational force.
Parts of 16 states have the highest risk for earthquakes: Alaska, Hawaii, California, Oregon, Washington, Nevada, Utah, Idaho, Montana, Wyoming, Missouri, Arkansas, Tennessee, Illinois, Kentucky and South Carolina. With the update, new high-risk areas were added to some of those states.