The swarm of earthquakes that rattled Edmond this week reveal a previously unknown fault line and could signal additional shaking in the area, according to seismologist Daniel McNamara. The research geophysicist at the U.S. Geological Survey’s Geologic Hazards Science Center in Golden, Colo., has been studying the state’s ongoing earthquake swarm. Researchers have used oil and natural gas industry data and other maps to identify previously undocumented fault lines. But sometimes faults are revealed when a series of earthquakes fire off with epicenters in a linear pattern.

“These are all ancient faults that have not been active since the days of the dinosaurs,” McNamara said. “They’re being reactivated at depth. They don’t even come to the surface. They’re all 5 to 10 kilometers down.”

This week’s quakes indicate a fault that runs northeast at least two miles from near Interstate 35 and Second Street, McNamara said. Because the newly revealed fault is not on any existing fault map, it’s difficult to tell how far it extends or whether it underlies more of Edmond or connects to a larger fault, he said. FULL REPORT