An earthquake measuring 5.0 on the Richter scale hit near the crude storage and transportation hub of Cushing, OK, on Sunday and spawned at least six aftershocks, but no damage was reported to energy-related infrastructure in the city.
According to U.S. Geological Survey (USGS) data, the 5.0-magnitude earthquake struck 1.2 miles west of Cushing at 7:34 p.m. CST on Sunday, at a depth of 3.1 miles. USGS picked up an aftershock measuring 2.6-magnitude less than an hour later, at 8:23 p.m., centered 1.2 miles north-northwest of Cushing and at a depth of 3.2 miles.
Data from the Oklahoma Geological Survey (OGS) show four additional aftershocks measuring 1.7-2.1 in magnitude struck the Cushing area all within about one hour of the 5.0 earthquake.
Robert Noltensmeyer, emergency manager for the City of Cushing, told NGI's Shale Dailythere was one injury from the earthquake, but it was not serious. He described a scene of broken windows and building facades in the city.
"We've got significant damage downtown," Noltensmeyer said Monday. "We've got a four-square block area cordoned off, and we've got the state insurance commissioner out there. We're doing damage assessment so we can put a game plan together in how we're going to clean it all up."
Oklahoma Corporation Commission (OCC) spokesman Matt Skinner said the commission's Oil and Gas Conservation Division (OCGD) was "working on an action plan to further modify Arbuckle disposal well operations in the area." He said the plan had not yet been finalized.
"The OCC's Pipeline Safety Department reports normal operation has resumed for pipeline operators in the Cushing oil storage terminal under state jurisdiction," Skinner said.
In a separate statement late Monday, Skinner said there were no damages reported at the Cushing oil terminal.
OGS Director Jeremy Boak told NGI's Shale Dailythat seismologists had expected to see larger aftershocks from the 5.0 quake, but they haven't materialized. He added that there have still been no reported aftershocks from the largest earthquake recorded in the state, a 5.8-magnitude temblor that struck on Sept. 3 near Pawnee, OK (see Shale Daily, Sept. 6).
Boak said the fault that caused Sunday's earthquakes and aftershocks in the Cushing area is the same fault responsible for a series of minor quakes that struck the city more than a year ago (see Shale Daily, Oct. 12, 2015). He added that many injection wells in the area were ordered shut in after the temblors in October 2015.
"We should see sometime this afternoon, maybe first thing tomorrow, a response from the OCC," Boak said Monday. "I think there are going to be additional new shut-in wells, more [intake volume] reductions. Others are already shut in. The discussion I heard this morning was that there might have be a larger view -- looking at the fact that if you go out 15 miles from this earthquake you're within 15 miles of the 4.5 [magnitude earthquake] last week [see Shale Daily, Nov. 4].
"You've got three fairly substantial earthquakes in a relatively concentrated area. It would not be surprising if we moved toward the kind of slightly-larger regional action that we saw in the earlier part of this year, where they took a large area in the West and Central parts of the state and put up a specific target for reduction in that area. And that has been achieved."
The OGCD unveiled its Western Regional Reduction Plan, which called for a nearly 500,000 b/d reduction in wastewater injection volumes, in February (see Shale Daily, Feb. 17). It released its Central Oklahoma Volume Reduction Plan, which called for a 300,000 b/d reduction in injection volumes, one month later.
The OGCD began ordering operators to either shut down or curtail intake volumes at injection wells in March 2015, shortly before scientists with the OGS attributed the increase in seismic activity to injection wells targeting the Arbuckle formation, which closely overlies the crystalline basement (see Shale Daily, April 22, 2015; April 2, 2015). The OGS said the disposal of extremely salty water -- a byproduct of oil and gas production, not the mostly freshwater used for hydraulic fracturing -- is responsible for the quakes (see Shale Daily, Jan. 5).
Boak pointed out that while scientists believe there is a link to an increase in induced seismic activity following an increase in wastewater disposal volumes, the obverse is true, too -- that with the decline in injection volumes there has been a corresponding decrease in earthquakes.
"There is equally strong evidence that there is a connection due to the fact that [seismic activity] has gone down when the injections went down," Boak said. "The decline in injection, more than 1 million b/d, produced a decline in seismicity. The attribution of one to the other is equally important in understanding what's going on here."
In a statement Monday, the Center for Biological Diversity (CBD) asked the Interior Department’s Bureau of Land Management to cancel 11 proposed oil and gas leases in Oklahoma, citing the latest earthquake near Cushing.
“We don’t need a major earthquake that claims lives and costs millions in damage to tell us the rapid increase in fracking and wastewater injection in Oklahoma and neighboring states is the cause,” said CBD spokesman Taylor McKinnon. “It’s only a matter of time until these increasing quakes cause catastrophic damage. Alongside the worsening climate crisis, earthquakes are yet another reason that President Obama should end the federal fossil fuel leasing programs now.”