 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.
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 (USGS) updated its national seismic hazard maps on Thursday 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 an important  part of the National Earthquake Hazards Reduction Program, a  partnership of four federal agencies to reduce risks of earthquakes. The  four agencies include USGS, the Federal Emergency Management Agency  (FEMA), the National Institute of Standards and Technology, and the  National Science Foundation.
Most high-risk zones are concentrated  on the west coast and Alaska, with a few other hotspots clustered  around faults in the Midwest and Southeast.
Most of the changes in  this year's updated map are relatively minor.  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.
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