Illinois and Missouri are on the list of states with the highest risk for earthquakes.
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 of the nation.
The U.S. Geological Survey updated Thursday 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 Midwest isn't typically thought of as a place at risk of a major earthquake. Illinois Emergency Management Agency Director Jonathon Monken says the chances are higher than most people would estimate. He says the U.S. Geological Survey says that in the next 50 years, there is a 10-percent chance that Illinois could experience an earthquake of the magnitude emergency responders are running practice exercises for this week. It's meant to test capabilities in the event of a quake in the New Madrid and Wabash Valley seismic zones.
Scientists said today that the New Madrid fault zone in the nation's midsection is active and could spawn future large earthquakes.
The journal Science published the study online. U.S. Geological Survey seismologist Susan Hough was part of the study. She says the fault zone is ``not dead yet.'' Researchers have long debated just how much of a hazard New Madrid poses. The zone stretches 150 miles, crossing parts of Arkansas, Illinois, Indiana, Kentucky, Mississippi, Missouri and Tennessee.
The U.S. Geological Survey says the shaking with a measured magnitude 3.2 in northern Illinois was a blast and not an earthquake.
USGS geophysicist Don Blakeman also says it appears Monday afternoon's blast came from within a rock quarry but that the exact location of the blast had not yet been determined. He says that all indications so far leads experts to believe that the blast came from the quarry. That includes that the epicenter is in an area close to the quarry.