A series of earthquakes struck about 11 miles northeast of Hermleigh in Scurry County, Texas, overnight, beginning with a 4.9-magnitude earthquake that struck about 10:38 p.m. on 22 July. The earthquake could be felt as far east as Dallas-Fort Worth.
That was followed by a 2.8-magnitude earthquake and a 4.4-magnitude earthquake about 10:46 p.m. and a 3.1-magnitude earthquake close to midnight. A 3-magnitude earthquake was also felt about 7:39 a.m. on 23 July.
“Across the Permian Basin region, there has been an increase in the rate of earthquakes felt at the surface,” said Peter Hennings, principal investigator for the Center for Integrated Seismicity Research at the University of Texas’ Bureau of Economic Geology.
Speaking with the Reporter-Telegram by phone, Hennings said those occurrences have been definitively linked to the injection of produced water.
“Subsurface injection of produced water, especially deeper beneath the shales, causes pore pressure increases that, combined with existing faults, can cause a rupture and cause an increase. If the fault ruptures more abruptly and over a larger region, it can cause earthquakes like the 4.9-magnitude earthquake last night,” he said.