TEXAS — 2021 marked a new high for earthquakes in Texas, and human activity is to blame for most of it.
209 - that's how many earthquakes magnitude 3 or greater rattled the Lone Star State last year. It's more than double the number in 2020. Most were concentrated in western Texas, and some scientists say fracking is the culprit. Some areas are noticing not just a rise in quake numbers, but intensity as well.
"In the northern part of the Texas Delaware Basin, last year we had an increase in the magnitude as well," said Alexandros Savvaidis, a research scientist with the Bureau of Economic Geology at UT-Austin.
15 earthquakes of a magnitude greater than 4 occurred in Texas last year.
Oil drilling produces a lot of wastewater as a byproduct, and producers typically get rid of that water by shooting it back into the ground. That can slowly increase the pressure on fault lines until something slips.
Even if all fracking was to cease operation tomorrow, the Permian Basin would likely continue to experience earthquakes for months.
"From the time that we start injecting the water into the subsurface, until the time we have an earthquake, it might take a few months to more than a year," said Savvaidis.
The earthquakes became so frequent that the Texas Railroad Commission, the agency that regulates the oil and gas industry in Texas, suspended water injections in a small region just outside Midland and Odessa. 33 disposal wells were shut down as a result.
Through a network of seismometers, the Jackson School of Geosciences at UT-Austin is helping the commission locate new areas that may need restrictions on water injections. The seismometers are overseen by the TexNet Seismic Monitoring Program.
"We've actually placed more seismometers in these areas of high seismicity, to give us the best understanding of what's going on in the subsurface," said Mark Blount of the Bureau of Economic Geology.
With new drilling sites popping up, and underground wastewater being on the move, hot seismic zones come and go. That makes it tough to predict just how many earthquakes might rattle Texas this year.
"We see other seismicities migrating to nearby areas, so that means it is too difficult to understand where things will go for 2022," said Savvaidis.
So far, damage to property and infrastructure in the Permian Basin has been minor, but it has still led some homeowners to think about adding earthquake insurance to their policies.
