earthquake cluster in Idaho Panhandle

“We’re a long way from the nearest plate boundary,” said Ken Sprenke, a professor of geophysics at the University of Idaho, explaining the Yellowstone hot spot is too far away to have caused the four earthquakes that shook North Idaho late Thursday and again Friday. “These are a real mystery.”

http://www.spokesman.com/stories/2015/apr/25/idaho-earthquake-cluster-a-real-mystery/

Please check this EQ hazard map: http://news.yahoo.com/half-us-faces-earthquake-risk-171919389.html Roughly half the US population is at some appreciable degree of risk from EQs, and that is only parially relevant to distance from a plate boundary.....