Submitted via IRC for Bytram
Catalog of north Texas earthquakes confirms continuing effects of wastewater disposal
In their report published in the Bulletin of the Seismological Society of America, Louis Quinones and Heather DeShon of Southern Methodist University and colleagues confirm that seismicity rates in the basin have decreased since 2014, a trend that appears to correspond with a decrease in wastewater injection.
However, their analysis also notes that new faults have become active during this period, and that seismicity continues at a greater distance from injection wells over time, suggesting that "far-field" changes in seismic stress will be important for understanding the basin's future earthquake hazard potential.
"One thing we have come to appreciate is how broadly injection in the basin has modified stress within entire basin," said DeShon. The first thing researchers noted with wastewater injection into the basin "was the reactivation of individual faults," she added, "and what we're now starting to see is essentially the leftover energy on all sorts of little faults being released by the cumulative volume that's been put into the basin."
[...] The researchers found that overall seismicity in the Fort Worth Basin has been strongly correlated in time and space with wastewater injection activities, with most seismicity occurring within 15 kilometers of disposal wells.
Tracking Induced Seismicity in the Fort Worth Basin: A Summary of the 2008–2018 North Texas Earthquake Study Catalog [DOI: 10.1785/0120190057] [DX]
(Score: 1) by khallow on Thursday June 13 2019, @02:42AM
Then why is the energy release from these earthquakes on the order of the energy put into the system by the water pumping? In addition, earthquake frequency of these regions scales inversely as the energy released by the earthquake, not its moment. That's typical of slippery faults that don't have a lot of potential to build up energy for earthquakes, not faults that have a lot of potential energy waiting for release.