CAPE GIRARDEAU, Mo. (AP) - The U.S. Geological Survey is conducting low-level flights across sections of Missouri, Arkansas and Tennessee this week looking for clues about the New Madrid earthquake fault zone.
The USGS begins conducting the flights Wednesday over a 1,400-square-mile area across southeastern Missouri, northeastern Arkansas and western Tennessee. Crews will be measuring the magnetic field of the earth and underground rock formations to help locate concealed faults associated with the New Madrid seismic zone.
The USGS says the New Madrid area has been the most seismically active region in the United States east of the Rockies for decades.
The USGS says while there's no evidence of an imminent large earthquake, the agency has serious concerns about the potential repeat of a destructive earthquake like those that occurred in the 1800s.
There are no immediate reports of damage after four earthquakes rattled central Oklahoma overnight.
The U.S. Geological Survey reports that an earthquake and a series of aftershocks began about 1:45 a.m. Central Time with a magnitude 3.0 quake centered about 3 miles west-southwest of Chandler, Oklahoma.
That was followed a few minutes later by a magnitude 4.3 quake near Oklahoma City. US Geological Service puts the epicenter of the quake 7 miles east-northeast of Luther, Oklahoma, and about 29 miles east-northeast of Oklahoma City.
At 2:15 a.m. the ground shook again. This time a 2.8 magnitude quake struck about 54 miles east of the capital, followed a minute later by a 3.3 magnitude temblor about 4 miles east of Luther.