If you felt the earth move under your feet this past weekend, you were not alone.
Four distinct earthquakes that rattled Johnson and Navarro Counties began at 5:44 a.m. June 23, about 4 miles northeast of Keene. The first registered 2.1 on the Richter scale, according to the U.S. Geological Service. A second quake hit at 12:46 p.m. June 24 in almost the same spot, but was registered at a higher intensity of 3.6.
“I thought a truck hit my house,” said Becca Miller of Keene, whose home at the southeast corner of South College Drive and First Street in Keene was damaged in the second earthquake. Keene police dispatcher Elizabeth Barber received calls from concerned residents saying items were knocked off walls and shelves, but no damage was reported, she said. The Emergency Dispatch Center in Burleson reported feeling the quake.
“I rushed outside, but there was no truck,” Miller said. “It took a few seconds for me to realize we had an earthquake.” Miller's house sustained cracks in the walls of two rooms, a separation in the roof at the gable, and a foundation that dropped a couple of inches on the east side. “Those cracks in the walls and at the gable weren't there Sunday morning,” she said.  The third earthquake — a 2.2 tremor – struck about 1 a.m. Monday near Corsicana, according to the USGS. The fourth quake s epicenter was just 1 mile south of Alvarado at 11:03 p.m. Monday and registered
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at 2.6. I felt the concussion of the earthquake, Burleson resident Matt Gregg said. It felt like a transformer had blown, and I didn t realize until I got to work the next day that it had actually been an earthquake. Earthquakes have been the center of attention in the area this past year since two quakes in Cleburne were registered June 12, 2011, with magnitudes of 2.7 and 2.4. Five separate earthquakes had been registered since that time until this weekend in Johnson County by the USGS. There has been an increase in ground movement in North Texas and along the Balcones Fault Zone, according to the USGS. The fault zone, which is generally considered to be among the lowest-risk fault zones for earthquakes in the United States, stretches from San Antonio into Dallas and runs nearly parallel with Interstate 35W. Some have speculated whether the quakes are the result of fracking hydraulic frac­tur­ing or frack­ing is a process used to extract nat­ural gas that lies within a shale rock for­ma­tion thou­sands of feet beneath the earth's surface or Mother Nature.
"My office shook and it was frightening," Southwestern Adventist University professor of nursing Bonnie Gnadt said. Chesapeake Energy and Devon Energy, both of which utilize fracking technology in drilling for natural gas, did not return calls to the Alvarado Star by press time.
The Barnett Shale, which stretches from Dallas County to the west past Fort Worth, has about 100 waste injection wells and nearly 20,000 natural-gas production wells, almost all of them drilled in the past five years. In a recent study by South­ern Methodist Uni­ver­sity and the Uni­ver­sity of Texas, a rash of small earth­quakes in the North Texas area in 2008 and 2009 was linked to deep injec­tion wells used to dis­pose of nat­ural gas waste­water. But as the study's authors point out, many sim­i­lar wells oper­ated in areas where no seis­mic activ­ity occurred.
The Army Corps of Engi­neers has expressed con­cern about drilling for nat­ural gas near dams and has a national team study­ing the poten­tial impact. The Corps has requested a 3,000-foot buffer around dams because it wor­ries that frack­ing near fault lines could cause earth­quakes or shifts in sed­i­ment that would weaken dam struc­tures, according to a Corps press release. USGS geophysicist Don Blakeman says it s difficult to determine why quakes occur.
The largest earthquake on record in Texas occurred August 16, 1931, when a 5.8 magnitude earthquake hit near Valentine in Jeff Davis County near Big Bend.