By Tim Farley

Managing Editor

Oklahoma County has experienced more earthquakes this year than in the previous 120 years, according to the Oklahoma Geological Survey.

Ken Luza, a geologist with the state agency, said 19 earthquakes have been recorded in the county this year with the majority of them occurring in the Choctaw-Luther-Jones area. Oklahoma County had seven earthquakes from 1889 to 2005, according to the state’s geological survey. The county had four recorded quakes in 2006, none in 2007 and three in 2008.

“It’s unusual to see this many in Oklahoma County,” Luza said. “They’ve all been small with the largest one at 3.5. Normally, these types of earthquakes don’t produce damage. When we see a number of them in one area over a short period they’re called swarms.”

Luza said most swarms last only days or weeks.

“In this case, it’s been nine months,” he said. “It happens sometimes. Swarms will often occur in a place that normally doesn’t have earthquakes.”

Luza said geologists are unable to explain this most recent phenomenon.

“We just don’t know for sure,” he said. “The earthquakes that have been occurring in Oklahoma County have not produced any surface rupture and they’re not associated with any known named faults. But it’s good to have small earthquakes because it releases stored up strained energy.”

Five earthquakes were reported in the Choctaw area from Nov. 2 to Dec. 7, according to information on the Oklahoma Geological Survey’s Web site.

The most recent earthquake occurred Monday, Dec. 7, at 11:45 a.m. The quake was felt by several people throughout the area, including Choctaw High School wrestling assistant coach Brian Garcia, chamber of commerce executive Tracy Mosley and fire department secretary Susan Johnson.

Garcia said he was in the high school wrestling office when he felt the tremor. He said the quake lasted “only a brief time, but you knew it was an earthquake.” Mosley said she was on the phone when “it felt like my building popped and it jarred my chair. It was just for a split second. I thought maybe it was an earthquake and then I knew for sure when I watched the news that night.”

Johnson said she knew right away what was happening.

“It was like being on a boat. My chair and everything in the office was shaking. It was an eerie feeling. The guys who were with me in the office noticed it,” she said.

The U.S. Geological Survey reported the earthquake occurred 3.1 miles under the earth’s surface. The quake’s epicenter was reported five miles north of Choctaw and two miles east of Jones, according to the USGS Web site.

Oklahoma has a few areas that have produced earthquake trends, including the Norman-Purcell area, Canadian County, the Anadarko Basin and now eastern Oklahoma County, Luza said.

The most damaging Oklahoma earthquake occurred in April 1952 when a 5.5 magnitude tremor hit the El Reno area.