Two earthquakes that recently shook the area around the East Texas town of Timpson were unlikely to have been caused by natural gas drilling or drilling waste disposal activities, according to the Railroad Commission of Texas (RRC).

Last Thursday, Timpson residents felt a 4.3 magnitude earthquake after experiencing a 3.9 magnitude quake the week before. Elsewhere in the country, drilling waste disposal or injection wells have been blamed for seismic activity (see Shale Daily, April 17).

"Commission staff have inspected commercial disposal wells within the vicinity of these minor seismic events in East Texas. No Railroad Commission rule violations were found, and the wells were operating within their permit conditions," said RRC spokesperson Ramona Nye.

"With more than 30,000 injection and disposal wells, Texas has a long history of safe injection, and Railroad Commission staff has not identified a significant correlation between seismic activity and injection practices. Commission regulations require injection be confined to a permitted interval, and if faults, stratigraphy, or any other geologic phenomena are identified as a concern, they are evaluated.

"In addition, Commission staff could suspend or terminate an injection well permit if science and data indicated a problem."

Timpson is in Shelby County, 170 miles north of Houston, 175 miles southeast of Dallas and 65 miles southwest of Shreveport, LA.