Oklahoma feels aftershocks of the big one

SPARKS, Okla., Nov. 6 (UPI) -- Aftershocks struck a jittery Oklahoma Sunday following a weekend of quakes, officials said.

The quakes included the largest in state history Saturday night, with a magnitude of 5.6, the Los Angeles Times reported.

The heaviest aftershock was at 4.0 magnitude at 3:40 a.m. CST Sunday, the U.S. Geological Survey in Golden, Colo., reported. The Times said the USGS was installing more sensors in the region to analyze the series of quakes.

Austin Holland, a research seismologist with the Oklahoma Geological Survey based at the University of Oklahoma in Norman, told the Times were at least 10 aftershocks of 3.0 or more since the quake Saturday night, adding, "there's many, maybe hundreds, that are going unfelt."

Meanwhile, damage assessment began in central Oklahoma Sunday after the record 5.6-magnitude earthquake shook the region, emergency officials said.

Lincoln County Emergency Management Director Joey Wakefield told KOKI-TV, Tulsa, Okla., three homes sustained significant damage and Highway 62 buckled in three places near Prague Saturday night. A vehicle-sized boulder also came to rest on the roadway.

The TV station said there also were reports of damage in Muskogee.

Aaron Bennett of Lincoln County emergency management told CNN one man in Prague suffered minor head injuries when he tripped while running out of his house.

The 10:53 p.m. quake was centered about 4 miles east of Sparks, Okla., and 44 miles north-northeast of Oklahoma City at a depth of 3.1 miles, the U.S. Geological Survey said. The shaker came less than 21 hours after a 4.7-magnitude quake hit at 2:12 a.m. about 6 miles southeast of Sparks.

"The picture by the TV fell off the wall and we jumped up because we thought somebody had hit the house," Noeh Morales told The (Oklahoma City) Oklahoman after the latest quake.

"It woke me out of a dead sleep. I felt the whole house shaking. I jumped and ran outside to see what was going on," he said.

The early-morning quake was followed by at least 40 aftershocks up to magnitude-3.4, Oklahoma Geological Survey seismologist Austin Holland told The Oklahoman.

At 5.6-magnitude, the evening temblor surpassed a 5.5-magnitude quake near El Reno in 1952.