People in Dallas were surprised by a swarm of small earthquakes that started shaking the city a couple of days ago. There have been 11 by last count. And the quakes, though new to the Dallas area, are just the most recent in a major upsurge in earthquakes in Texas over the last few years.
Earthquakes were pretty much unheard of in the Dallas area until 2008. Since then there have been a lot of these swarms of quakes. In Irving, Texas, where this new cluster is located, there have been more than 50 in the last several years, according to the city manager. This current swarm started around September.
Possible explanations
This all started happening in 2008. That year also marked the boom in oil and gas exploration in Texas. A lot of people say there’s a link there. Not just in Texas, but across the country, studies have shown how injecting fluids into the ground can cause quakes. In the oil and gas business, people use injection wells for storing drilling waste water.
Not just in Dallas
It’s happening in Ohio, in Arkansas, in Louisiana. North Texas isn’t the only place feeling quakes. When these quakes strike around Dallas or Fort Worth, people pay attention. There are a lot of people there. A lot of them are politically engaged. When a swarm hit near the town of Azle more than a year ago, that prompted the state’s oil and gas regulator – the railroad commission – to actually hire a seismologist. But there have been quakes in other parts of Texas as well.
In fact, just an hour or so after the 3.5-magnitude quake hit Dallas on Tuesday, a quake of equal strength hit near Snyder in West Texas. Snyder has seen a lot of quakes lately, and at least one study suggests that’s due to drilling activity. In East Texas, towns like Timpson have had quake swarms. There are disposal wells around there. But we don’t hear as much about that because there are fewer people.
Heather DeShon is a seismologist at Southern Methodist University who is studying these quakes. She says there was a quake in Irving in November that didn’t get nearly as much attention.
“The 3.3 that occurred in November occurred on a Saturday night at like 9 p.m., and these are in Irving. The events are pretty close to businesses and things like that, so a lot of those buildings are empty,” DeShon said.
What comes next
The railroad commission said it is not investigating these quakes, though it just hired a seismologist. A spokesperson for the agency said investigating quakes is not that person’s job. Instead, he puts communities in touch with SMU researchers like DeShon. SMU just put a new seismic monitor in the area, and it announced today that it will deploy 22 more in the coming days to study the quakes.
But DeShon said studies like these can take years before they have some results. The SMU team is still working on producing a paper from their research on the Azle quakes last year.
In the meantime, it seems a safe bet there will be more earthquakes in Texas.
