An earthquake with a magnitude of 2.5 to 3 is the smallest generally felt by people. A magnitude 4 can cause moderate damage, a magnitude 5 considerable and a magnitude 6, severe damage. A magnitude 7 earthquake is capable of widespread and heavy damage.
Williams said the central Oklahoma earthquakes have occurred at relatively shallow depths and could have the potential for causing more damage than quakes that begin at greater depths.
“You can have damage from something smaller than a magnitude 4, especially if an earthquake is shallow and closer to homes, so the energy doesn't get absorbed by the earth and dampened,” he said.
On Nov. 5, 2011, a 5.6-magnitude quake struck northwest of Prague, damaging more than a dozen homes and buildings and injuring at least two people. This earthquake broke the state's previous record for strongest recorded earthquake, a 5.5-magnitude quake in 1952 in El Reno.
Could more quakes of this size or bigger occur?
“I can't rule it out,” Williams said. “Oklahomans should continue to stay prepared for earthquakes, just like they prepare for tornadoes.”