Type of rock may have limited earthquake damage
BROWNVILLE, Neb. (AP) - The 5.6 magnitude earthquake that struck north-central Oklahoma apparently did not cause significant damage partly because of the type of rock beneath the region.
Geophysicist Jefferson Chang with the Oklahoma Geological Survey said a hard, or competent, bedrock crosses north-central Oklahoma while the subsurface around Prague is softer. Chang said the harder rock absorbs more of an earthquake's energy, reducing potential damage.
Emergency officials say the Saturday morning quake northwest of Pawnee led to sandstone facings of some buildings falling, but that no buildings collapsed.
The quake is the same magnitude and approximately the same depth as a 2011 earthquake near Prague, about 60 miles to the south. In that quake, two towers collapsed at a university in nearby Shawnee.