From Staff and LSNG Reports
Recent earthquakes in the area have officials looking at dams and infrastructure to make sure no damage is present or could develop later.
Inspections of the earthen dam at Eagle Mountain Lake are taking place while Brazos River Authority officials said they inspected the Morris Sheppard Dam at Possum Kingdom Lake on Thursday following two ground rattlers earlier that day north of Mineral Wells, the strongest a 3.6 magnitude.
There have been nearly two dozen area earthquakes, including 17 in the Springtown-Azle-Reno area of Parker County, recorded since early November.
BRA public information officer Judi Pierce said her office completed an inspection of the Possum Kingdom Lake Dam “first-thing” Thursday morning, per an internal policy stating the BRA inspects the dam after any kind of quake within 60 miles.
Pierce said the BRA is only required to inspect the dam if there is a 4.4-magnitude quake within 15 miles of the lake or a 5.0-or-higher quake within 12 miles, because of stipulations set by the Federal Energy Regulatory Commission.
“We have seen no indication that there was any kind of shifting or cracking [in the dam],” Pierce told the Mineral Wells Index. “It’s an abundance of caution for us. We’re expecting there may be more [earthquakes].”
The two local quakes are only the latest in a series of North Texas earthquakes stretching from Richland Hills to 14 miles southwest of Jacksboro. The bulk of these quakes have been concentrated in the areas around Azle and Springtown. Mineral Wells’ 3.6 magnitude quake matched the strongest yet documented over the past month, with the other 3.6 occurring northwest of Azle on Nov. 19.
Although the 3.6 shocks are by no means the strongest earthquakes in Texas history, based on information from the U.S. Geological Survey, they are rare for this area. The USGS and Texas Railroad Commission, which regulates Texas’ oil and gas industries, are studying the earthquakes and collecting data to try and determine a cause.
District 61 State Rep. Phil King, R-Weatherford, said there is no consensus amongst state geologists concerning a concrete cause for these recent earthquakes. King said although experts agree the tremors are benign, some experts believe they could be to the local oil and gas industry.
“There are some studies that suggest a correlation between the saltwater disposal wells and these minor earthquakes,” he said. “I don’t think that anybody legitimately thinks it’s the hydraulic fracturing or drilling itself. On the other hand, nobody really knows. However, what geologists have told me is that these levels of quakes are very common.
For example, West Texas gets them all the time. They’re not at a level anyone should worry about. They are a little bit of a nuisance, but that’s it.”
King said he is skeptical of connections to the oil and gas industry, primarily because of a discrepancy between the depth of the quakes’ epicenters are significantly lower than the depth for drilling and disposal wells in the Barnett Shale.
Both earthquakes in the Mineral Wells area occurred at a depth between 2.4 and 3.1 miles below the surface, whereas the average depth for crude oil and natural gas wells tends to be just over a mile, according to statistics from the United States Energy Information Administration.
King added the other half of his skepticism is largely pragmatic.
“There’s really no definitive scientific evidence to say that these earthquakes are caused by the industry,” he said. “There are over a million oil and gas wells in Texas. There are thousands of saltwater disposal wells. There have been tens-of-thousands of instances of hydraulic fracturing. So I’m a little suspicious [of the claim] that it might be causing earthquakes in Springtown.
“We’ve been drilling oil and gas wells for over 100 years, we’ve been doing hydraulic fracturing going on 15 or 20 years, we’ve been using saltwater disposal wells for decades; why is it just now that in North Texas it would be causing earthquakes? That’s why, from a pragmatic standpoint – not being a scientist – I ask a lot of questions.”
King explained that one reason scientists are not certain as to the cause of these recent earthquakes is they simply do not have the equipment necessary to hone in on these tremors at a “micro level.” These “sophisticated and targeted seismic monitors” that may be relatively commonplace in Northern California are few and far between in North Texas.
But King said he believes the cause of these earthquakes – however harmless – will continue to be thoroughly investigated by leading state geologists and researchers.
“I think there’s a lot of focus in the scientific community on this right now,” he said. “There are a lot of papers being written and studies being done. I suspect with all the concerns about it that there will continue to be.
“It is disturbing, I get that, too. All I care about is that the truth and facts be scientifically determined. I don’t want the environmental community trying to use this to shut down our oil and gas production in North Texas. That’s why my insistence is ... let’s make absolutely sure there’s hard-core scientific evidence, not just correlations and rhetoric.”