Number Of Earthquakes Increases Sharply In Texas

The chart above uses information from the Bureau of Economic Geology at the University of Texas. It shows that the number of magnitude 3 earthquakes (or greater) more than doubled in Texas in 2021 (from slightly less than 100 to more than 200). Texas has never been a hotspot for earthquakes, but the oil companies are changing that by their use of fracking.

The following is part of an article by Erin Douglas in The Texas Tribune:

More than 200 earthquakes of 3 magnitude and greater shook Texans in 2021, more than double the 98 recorded in 2020, according to a Texas Tribune analysis of state data maintained by the Bureau of Economic Geology at the University of Texas at Austin.

The record-setting seismic activity is largely concentrated in West Texas’ Permian Basin, the most productive oil and gas region in the state. Scientific studies show that the spike in earthquakes is almost certainly a consequence of disposing huge quantities of contaminated, salty water deep underground — a common practice by oil companies at the end of the hydraulic fracturing process that can awaken dormant fault lines.

During hydraulic fracking, oil companies shoot a mixture of fluids and sand through ancient shale formations, fracturing the rock to free the flow of oil. But oil isn’t the only thing that’s been trapped underground for millions of years: Between three and six barrels of salty, polluted water also come up to the surface with every barrel of oil.

The cheapest, and most commonly used, way to dispose of this “produced water” is to drill another well and inject it into porous rock formations deep underground.

For years, oil companies have loaded those formations with hundreds of millions of gallons of the black watery mixture — which contains a slurry of minerals, oil and chemicals used in fracking — every day, slowly increasing the pressure on ancient fault lines. An analysis by Rystad Energy provided to The Texas Tribune found that the amount of wastewater injected underground in the Permian Basin quadrupled in a decade, from 54 billion gallons in 2011 to 217 billion gallons last year.

In a 2021 study published in the Journal of Geophysical Research, scientists at the U.S. Geological Survey and the University of Texas found that the vast majority of seismicity since 2000 near Pecos — a city roughly 100 miles southwest of Midland — was likely triggered by increased wastewater disposal. State regulators, too, have found that an increase in seismic activity most likely occurs as a consequence of saltwater disposal.

“The cumulative volumes [of water] increase the pressure, and that is the force that triggers the fault to slip,” said Alexandros Savvaidis, a research scientist at the Bureau of Economic Geology at UT-Austin.

The result is that communities like Gardendale, where Bock lives, as well as the bustling cities of Odessa and Midland — which many oilfield workers, engineers and service workers call home — are experiencing not only more frequent earthquakes, but stronger ones.

Between 2018 and 2020, Texas recorded nine earthquakes above magnitude 4, almost all of them in the western half of the state. Last year, Texans were shaken by 15 earthquakes above magnitude 4 — including a 4.6 magnitude earthquake in late December that rattled homes from an epicenter about 30 miles northeast of Midland.

"Fracking" Is The Likely Cause Of Texas Earthquakes

(This image is from napavalley.edu.)

Fracking is the pumping of huge amounts of water, sand, and dangerous chemicals into the ground to cause or increase fractures in the rock, which releases natural gas. There is a heated debate going on about the safety of this fracking. Gas companies claim it is a safe procedure. Many others disagree, claiming it poisons the earth around it and the water many communities depend on.

Now there are claims that this fracking is having another negative effect. That it is causing earthquakes in Texas (and Oklahoma) -- areas that have been earthquake-free for eons, but having been experiencing them since 2008 (when fracking became common in the area).

Is this true? Very likely. Now there is some scientific evidence that those earthquakes, some as large as a magnitude 4, are being caused by fracking. Here is part of an excellent article on this by Anna Kuchment in the Dallas Morning News:

Scientists presented new evidence this week suggesting that all five North Texas earthquake sequences, including those in Dallas, have been triggered by humans.   

Until now, researchers have not commented on the cause of the Dallas-Irving quakes or the 4-magnitude quake that struck Venus, 30 miles south of Dallas, in May.

While scientists believe that high-volume injection wells may have triggered the quakes in Venus, they have not yet worked out a specific mechanism behind the Dallas and Irving quakes.

“We don’t think they’re natural,” SMU seismologist Heather DeShon told The Dallas Morning News.  “But we don’t understand the subsurface physics surrounding the Irving earthquake sequence, so we’re still considering all causes.”

DeShon’s comments came during the annual American Geophysical Union meeting in San Francisco, where she and her colleagues presented their latest research on North Texas ground shaking. The research has not yet been independently vetted and published.

“Any discussion of causation for the Dallas-area quakes is premature, and more speculative than scientific,” said Steve Everley, a senior advisor for Energy In Depth, a program of the Independent Petroleum Association of America. “But the SMU team has helped advance our understanding of the conditions that can ultimately lead to induced seismicity, so we’re eager to see what they will publish about the seismic events near Dallas.”

Evidence that human activity is behind the Dallas quakes includes a new analysis showing that the faults beneath Dallas and Fort Worth had been dormant for hundreds of millions of years until 2008, the year felt earthquakes first began rumbling through the area. . . .

Earlier this week, SMU seismologist Beatrice Magnani compared North Texas faults with those known to have produced earthquakes over geologic time. Active faults have visible ruptures, while the small faults that the SMU team has mapped in Azle and Venus have barely perceptible ones.

Unlike historically active faults, those in North Texas also do not extend into the uppermost layers of sediment.  Faults that have been active over hundreds of millions of years typically disturb the uppermost layers of the Earth’s crust, said Magnani.

“Those faults are dead, and they have just been rejuvenated. That is the most reasonable conclusion,” said Magnani, referring to the faults beneath North Texas. . . .

DeShon and her colleagues pointed to the absence of earthquakes in the Dallas-Fort Worth area prior to 2008 as additional evidence that recent tremors are caused by industrial activity. Since 2008, North Texas has had 200 earthquakes large enough to be included in the U.S. Geological Survey’s catalog. Thirty-one quakes have been larger than 3-magnitude.

Magnani said the state’s earthquake rate is on track to be a factor of 20 greater than historic levels. That pales in comparison to Oklahoma, which has seen a 600-fold increase in quakes. Oklahoma’s geological survey said in April that its quakes are triggered by the injection of wastewater from oil and gas operations into deep wells. Studies have found that pressure from the injections can, in rare cases, disturb deep faults. . . .