Scientists are saying 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.
Scientists analyzed past quakes in the New Madrid region and used computer modeling to determine that the continuing tremors are not related to the big quakes two centuries ago.