SMU's initial report of data collected from seismometors placed in Irving is interesting, provides a bit of useful context for the recent rash of quakes and promises further action. It does not, however, fill us in on what we're all so curious about -- whether or not the resource extraction process that's name shall not be mentioned has anything to do with the North Texas ground trembling for the first time in recorded history.
What the data collected so far does do is come closer to determining the exact epicenters of the quakes in the swarm. The SMU researchers pinpoint the beginning of the swarm as April 17, when the first felt earthquake hit Irving, registering 2.4 on the Richter scale. On January 6 the two biggest quakes of the swarm hit, a 3.5 and 3.6, setting off the questions and accusations that have come throughout the past month.
As recorded by Heather DeShon, Brian Stump and the rest of the SMU team, the majority of the quakes have centered on a two-mile line from Irving to West Dallas. The line, the researchers say "indicates the approximate location of a subsurface fault."
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As for nearby hydraulic fracturing activity, the nearest wastewater disposal well is about 8 miles to the northwest. There is a production well near the epicenters that ceased operation in 2012. Figuring out whether the wells have anything to do with the quakes or if their and the quakes' arrival together was just a cosmic coincidence is among the next steps according to Deshon and Stump. From an SMU press release:
"This is a first step, but an important one, in investigating the cause of the earthquakes," Stump said. "Now that we know the fault's location and depth, we can begin studying how this fault moves - both the amount and direction of motion."
"Then we can move on to what might have triggered it - examining factors both natural and manmade," DeShon said. "Sometimes what triggers an earthquake can be very small, so all of these factors have to be considered when looking for that trigger."