Ancient fault lines may have become re-activated

On June 18, 2002, a magnitude 5.0 earthquake occurred in southern Indiana, followed by a 1.2 magnitude aftershock on June 25, 2002. Because the region of occurrence, the Wabash Valley Seismic Zone, is seismically active, Dr. Won-Young Kim, a seismologist with the Lamont-Doherty Earth Observatory at Columbia University, conducted research to determine the potential hazard of future earthquakes to this region. His findings suggest that an ancient fault line dating back to the Precambrian era of geological history (from 4.6 billion to 570 million years ago) has become reactivated and was the likely cause of the June 2002 earthquakes. Kim is presenting his findings at the Seismological Society of America in May, and publishing in the Bulletin of the Seismological Society of America.