The following is from the June 9, 2009, edition of KERA public radio. Brian Stump, a professor and seismologist with the Roy M. Huffington Department of Earth Sciences in SMU's Dedman College, provided expertise for this story.
June 9, 2009
Three earthquakes in a week have rattled Cleburne-area residents. KERA's BJ Austin says the quakes didn't do any damage but residents are wondering what's going on beneath the Texas prairie, southwest of Fort Worth.
Cleburne 9-1-1 started getting calls about the latest earthquake shortly after 8 Monday morning . . .
The third earthquake was less than 24 hours after the second. The first was last Tuesday. They ranged from 2.8 to 2.3 on the Richter scale. Cleburne Mayor Ted Reynolds says there hasn't been any damage and the U.S. Geological Survey tells him the small quakes are not big deal. But, they are a unique event for Cleburne as far as he can remember and something of mystery.
But, SMU Professor of Earth Sciences, Brian Stump is not so sure gas drilling on Barnett Shale has any connection.
Stump: Even if it was related to the Barnett Shale, the little events probably are naturally occurring stresses that are in the crust that are being relieved. And I would say little stresses. These are really small events. I will say, though, and not for this application, but there are places where infrequently when people have either injected fluids into the crust or extracted fluids, they have triggered small earthquakes: infrequently and small. And I can't rule out that that might not be going on here. But certainly we don't have enough information to say one way or the other.
Stump does say it's important to gain some perspective on the Cleburne quakes and those last fall and last month in the Mid-cities/Irving area. He says there are roughly 100 thousand magnitude three earthquakes around the world each year and a MILLION magnitude two. It generally takes a FIVE before damage occurs.
Read the full story or listen to the broadcast.
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