Update, 9:56 a.m. Wednesday: A 10th earthquake has shaken North Texas since Tuesday morning. The U.S. Geological Survey says the 10th quake struck at 8:34 a.m. Wednesday in Irving, near the old Texas Stadium site.
That’s where most of the other quakes have been recorded in the past 24 hours.
The first quake struck the Irving area at 7:30 a.m. Tuesday. The second was recorded shortly after 3 p.m. – it was 3.5 in magnitude. Another one struck at 6:50 p.m.
They kept coming … and coming … and coming. But as Tuesday evening progressed, they tended to get smaller.
More quakes came at 8:11 p.m. and 8:12 p.m. Then two more around 10 p.m. Another one struck at 11:02 p.m. Earthquake No. 9 was recorded at 12:59 a.m. Wednesday.
They’ve ranged in magnitude from 1.6 to 3.6.
Some of the quakes have been felt in several cities across Dallas-Fort Worth. There are no reports of significant damage.
The 3.6 quake is the strongest to hit Irving. In recent months, more than 20 quakes have rattled Irving around State Highways 114 and 183 – near the old stadium land and a gas well site.
USGS geophysicist Jana Pursley says Tuesday’s quakes were the “largest since the earthquakes started happening there in the last year.”
The Irving quakes follows a rash of quakes in and near Azle, which is northwest of Fort Worth.
Some blame North Texas earthquakes on natural gas well drilling — and the use of disposal wells to store wastewater from the drilling. There’s been a gas drilling boom in the Barnett Shale, a massive geological formation that covers about 20 North Texas counties.
The Railroad Commission of Texas, the state’s oil and gas regulator, hired a seismologist last year. Commission members have adopted tighter disposal well rules.
The commission said this week it is not investigating the Irving quakes.
“The Railroad Commission is not investigating seismic activity around Irving,” Ramona Nye, a commission spokeswoman, told StateImpact Texas. “Specifically, there are no disposal wells in Dallas County, and there is only one natural gas well in the vicinity, and it is an inactive well.”
Stronger quakes have been recorded in North Texas. In 2013, two 3.6-magnitude quakes rattled Azle and two 3.7-quakes hit Mineral Wells, SMU earthquake researchers say.
Back in Irving, school district officials spent Tuesday afternoon checking campuses to confirm there wasn’t any damage.
Irving ISD spokeswoman Lesley Weaver at first thought someone bumped into a wall in the office.
“We could feel something in our administration building,” Weaver said. “I would describe it as a slight shaking and we all said ‘What is that?’ Someone who works here in our office and lives in Irving as well said: ‘That’s an earthquake.’”
SMU studying Irving quakes
Seismologists from SMU installed seismic monitoring equipment in northeast Irving Monday after the recent rash of minor earthquakes.
Irving City Manager Chris Hillman told KERA last week it was time to call in the experts.
“The frequency seems to have increased over the past month, month-and-a-half,” Hillman says. “So therefore we’re asking the experts from SMU to come in and help assist. They’re going to be bringing in some additional equipment to help monitor and get more information if another earthquake were to occur.”
In a statement on the university website, SMU seismologist Brian Stump said the SMU seismology team is “not currently engaged in a larger study of the cause of the Irving quakes.” But Stump plans to provide an update to the Irving City Council Jan. 15 “on what data might be expected from the Irving installation.”
Stump wrote on the SMU website:
This latest installation provides a third source of data SMU can tap in helping to determine the location of the Irving-area earthquakes. The seismology team also can retrieve data from a University-controlled portable seismometer previously installed at a site south of DFW airport, as well as the seismometer permanently installed in the basement of Heroy Hall on the SMU campus.
SMU experts have also monitored activity in the Azle area, where there was an earlier swarm of quakes. The quakes in and near Azle are considered relatively small, but they’ve been large enough to cause damage and raise alarm. Both the mayors of Reno and Azle believe there is a link to the disposal wells from oil and gas drilling in the area.
We’ve reported on SMU’s efforts to study the North Texas quakes. Here’s another story on SMU’s efforts. READ MORE