Quakes shake area residents

By Ann Kelley

Published: February 13, 2007

Three earthquakes, including one measuring 3.0 on the Richter scale, were felt by residents in the south metro area Monday.

The largest earthquake was recorded at 12:33 p.m., said Amie Gibson, seismic research specialist for the Oklahoma Geological Survey.

The epicenter was seven miles east of Norman on an unmapped and unnamed fault line, Gibson said.

The earthquake is tied as the second-strongest recorded in that area.

Seismologists in 1977 recorded a 3.0 magnitude earthquake.

Gibson said the largest quake to affect the region was April 9, 1952. It measured a 5.5 on the Richter scale.

Gay Graves, a receptionist at Midwest Trophy in Del City, said Monday she heard a boom and looked at co-worker Linda Cooper to see if she heard the same thing.

Their chairs were slightly pushed by what seemed like a quick, brisk wind, Graves said.

"It was a rolling feeling,” she said. "When it was over, we just looked at each other and both said ‘what was that?'”

Later Monday evening, two smaller earthquakes shook the area, said Jim Lawson, chief geophysicist for the Oklahoma Geological Survey. At 6:16 p.m. an earthquake measuring 2.7 on the Richter scale was recorded, followed by one at 6:35 p.m. which registered a 1.7 on the scale, Lawson said.

The Oklahoma Geological Survey received more than 150 reports from people who felt Monday's largest quake. Gibson said most described hearing what sounded like a clap of thunder and feeling the ground wobble for a few seconds.

No major damage was reported, she said.

Judy Welch, 58, said a recliner that her son, Kenneth Welch, 27, was sitting in moved away from the wall.

"I felt like the ground was going to fall in right under me,” Judy Welch said.

Four small earthquakes occurred Sunday in the same area, Gibson said.

The first quake occurred at 3:23 a.m., registering 1.5 on the Richter scale. The others followed at 7:31 a.m., 8:07 a.m. and 8:09 a.m. and ranged from 1.7 to 1.9 in magnitude.

Earthquakes measured at 2.6 and 2.7 on the Richter scale occurred in the same area on Dec. 21.

Lawson said it's highly unusual for the area to experience a large number of earthquakes.

Lawson said he suspects the earthquakes are caused by the same fault, but can't prove it because so many faults in Oklahoma have not been located or mapped.

More small earthquakes could occur, Lawson said. He said there is no predicting when they may happen, although he doesn't expect any to be large enough to cause substantial damage.

Contributing: Joe Wertz, Staff Writer