A new federal earthquake map dials up the shaking hazard just a bit for about half of the United States and lowers it for nearly a quarter of the nation.
The U.S. Geologic 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 temblor in 2011 in Virginia.
Most of the changes are slight. Project chief Mark Petersen said parts of Washington, Oregon, Utah, Oklahoma, Colorado, Wyoming and Tennessee moved into the top two hazard zones.
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.
Southwestern Missouri and northwestern Arkansas are in the low to moderate range of the hazard projections. Emergency management officials in those areas expect they'll have to take care of people who flee a major earthquake along the New Madrid fault in southeastern Missouri and northeastern Arkansas. They also expect hospitals in southwestern Missouri and northwestern Arkansas will have to treat people who are injured in a major earthquake to the east.