Another smaller earthquake hit East Texas Sunday. After Thursday’s second earthquake near Timpson, Texas in Shelby County - in as many weeks - injection wells from drilling are again a suspected culprit. Reports indicate more research is needed in East Texas to reach that conclusion, but even that might not be enough.
Earthquakes in the state are rare. That’s why UT Arlington geophysicist Glen Mattioli says any Texas temblor make people wonder what caused it.
Glen Mattioli: In north Texas , we don’t have a very high level of seismicity. It’s in fact one of the lowest levels of seismicity throughout the whole country.
Records show however that a small earthquake hit nearly the same spot 3 decades ago. Doctor Cliff Frohlich, at UT Austin’s Geophysics Institute, says the 3.9 magnitude quake on May 10th , followed by the 4.3 quake on the 17th, may have occurred naturally. But it could also have been triggered by nearby injection wells.
Frohlich: It isn’t like the injection is causing the earthquake, but faults are stuck. You know, when you go down a hill, you don’t slide down the hill because there’s friction between your shoes and the hill. On the other hand if someone puts you on an air hockey table with smooth shoes and turn on the air on the hill , you would slide down that hill. It could be fluid is being injected and its un-sticking a fault that’s ready to slip.
Frohlich says there just aren’t enough seismic devices to measure tremors in the region. More research is required, and Frolich says that’s what he’ll be involved with. But he says that’s at least several months away, if not longer.
The U.S. Geological Survey reports Sunday’s quake registered a 2.7 magnitude near Timpson, with not damages or injuries reported.
PDF: Texas Almanac's 2011 Quake Map
YouTube: Earthquake Review
