November 27, 2009
By Michael Kimball
The Oklahoman
Oklahoma County was all shook up in 2009.
While the number of quakes recorded by a seismograph has been below average this year in Oklahoma, the number strong enough to be felt is above average, the Oklahoma Geological Survey said.
Of those, more than twice as many earthquakes were felt in Oklahoma County this year than normally are felt in all of Oklahoma.
"We call those swarms,” said OGS director Randy Keller. "It’s not a big swarm, but it’s interesting. ... They’re very small earthquakes.”
The biggest quake in Oklahoma this year was 3.7 on the Richter scale and struck Aug. 28 in eastern Oklahoma County, near where three temblors have been recorded this month. That quake is far in intensity from the last deadly earthquake in the United States which killed two people in December 2003. It measured 6.6 and was centered near Paso Robles, Calif., according to the U.S. Geological Survey.
Scientists aren’t sure what’s causing the increase in Oklahoma, but Keller said there’s no need for alarm.
"What people maybe don’t appreciate is just how complex the subsurface structure in Oklahoma is,” he said. "There are lots of faults, some quite large.”
Earthquakes that wouldn’t be felt in places like California, where subsurface conditions are different, can be felt here, Keller said. The hard rock beneath the Sooner State is better at conducting the seismic waves.
"It’s kind of like you’re hammering onto the end of a nice piece of metal,” Keller said.
Recent Events
Mag. 3.0 2009/11/28 19:36:58 35.566N 97.274W 5.0 8 km ( 5 mi) SSE of Arcadia, OK
Mag. 2.1 2009/11/25 10:51:39 35.529N 97.273W 5.0 14 km ( 9 mi) NE of Midwest City, OK
Mag. 2.6 2009/11/22 23:47:12 35.493N 97.230W 5.0 16 km (10 mi) ENE of Midwest City, OK
Mag. 2.5 2009/11/16 05:12:37 35.493N 97.230W 5.0 16 km (10 mi) ENE of Midwest City, OK
Mag. 3.0 2009/11/14 05:13:01 35.524N 97.219W 5.0 18 km (11 mi) ENE of Midwest City, OK
Mag. 2.7 2009/11/02 12:27:05 35.432N 96.550W 5.0 17 km (11 mi) WNW of Bearden, OK
Mag. 3.0 2009/10/22 22:56:29 35.794N 97.017W 5.0 10 km ( 6 mi) ESE of Fallis, OK
Mag. 2.3 2009/09/08 09:03:12 35.633N 97.205W 5.0 12 km ( 7 mi) ESE of Arcadia, OK
Mag. 2.3 2009/08/27 23:15:50 35.566N 97.290W 5.0 12 km ( 7 mi) SSE of Arcadia, OK
Mag. 2.4 2009/08/27 22:30:55 35.566N 97.290W 5.0 12 km ( 7 mi) SSE of Arcadia, OK
Mag. 3.5 2009/08/27 21:09:06 35.565N 97.290W 5.0 12 km ( 7 mi) SSE of Arcadia, OK
Mag. 2.7 2009/08/27 13:32:06 35.566N 97.290W 5.0 12 km ( 7 mi) SSE of Arcadia, OK
Mag. 2.6 2009/08/27 12:13:52 35.566N 97.290W 5.0 12 km ( 7 mi) SSE of Arcadia, OK
Mag. 2.5 2009/08/27 10:31:24 35.566N 97.290W 5.0 12 km ( 7 mi) SSE of Arcadia, OK
Mag. 2.7 2009/08/27 10:17:52 35.566N 97.290W 5.0 12 km ( 7 mi) SSE of Arcadia, OK
Mag. 2.5 2009/08/27 07:58:25 35.566N 97.290W 5.0 12 km ( 7 mi) SSE of Arcadia, OK
Mag. 2.3 2009/08/14 15:08:58 35.467N 97.412W 5.0 2 km ( 1 mi) NW of Midwest City, OK
http://www.newsok.com/central-oklahoma-sees-more-quakes-this-year/article/3420715