USGS Sends Seismic Instruments to Payne County In Response to Heightened Earthquake Activity
OKLAHOMA CITY – The U.S. Geological Survey has sent several seismic measurement instruments to Payne County in response to the recent flurry of earthquakes in the area, particularly the two magnitude-4 temblors that shook the Cushing area last week.
State Sen. Jerry Ellis hailed the USGS announcement, noting that Cushing is a critical oil hub for the entire United States.
Cushing has an oil storage tank farm where 46 million barrels of oil are stored; that’s equivalent to the carrying capacity of 46 oceangoing supertankers. Cushing is the single largest oil storage facility in the world. Signs proclaim the Payne County town as the “Pipeline Crossroads of the World” because so many large transmission lines terminate and originate there. Cushing is the delivery point for West Texas intermediate, a U.S. light sweet crude oil.
“If a major earthquake were to strike Cushing and damage or destroy significant parts of that tank farm, it would be a matter of national security,” said Ellis, D-Valliant.
The USGS is “well aware of what’s going on” in Cushing, Bill Ellsworth of the USGS in Menlo Park, Calif., advised independent petroleum geologist Bob Jackman of Tulsa. The USGS sent some seismographic instruments to colleagues at Oklahoma State University last week, and more instruments were sent and were expected to be deployed Monday, Ellsworth wrote in an email Sunday.
Two USGS NetQuakes seismographs were installed last weekend near Cushing, at the airport and just west of town, said Robert Williams, Central and Eastern U.S. Coordinator of the USGS Earthquake Hazards Program.
Payne County has experienced more than two dozen earthquakes in a little over a month, including a 4.3-magnitude temblor last Friday and a magnitude-4.0 tremor last Tuesday.
Both of those ‘quakes had relatively shallow epicenters, but Williams said that shallow earthquakes often result in greater surface damages because they release more surface energy.
Physical, Psychological Impact from Tremors
So far the tremors in Payne County have caused only cosmetic physical damage, but the toll on nerves of residents is mounting.
“People are very concerned,” said Angela Spotts, of Stillwater. “Our houses weren’t built to withstand seismic activity of this intensity and duration.”
“It’s disconcerting,” added Rosemary Morehouse, who lives south of Cushing. “It’s something you can’t prepare for.”
Cushing City Manager Stephen Spears, an Oklahoma State University graduate who is a civil engineer, said the 4.3 ’quake rearranged ceiling tiles and caused new wall cracks at Cushing’s community center.
Patti Harris, data entry specialist with the City of Cushing, said the 4.0 ’quake “shook City Hall pretty good.” The temblor shut doors, opened filing-cabinet drawers, and opened upper cabinet doors in the break room, Harris said. Ceiling fans were swaying and plexiglass partitions were “rocking back and forth,” she said. “I was standing, and it felt like it was right under my feet.”
The earthquake Oct. 10 was of shorter duration but greater intensity than the one Oct. 7, local residents said. At City Hall, a concrete-block structure, ceiling tiles fell and a light fixture was dislodged “and is hanging from the ceiling.” The shaking last 10 to 15 seconds, during which “our computer monitors rocked back and forth and my chair was shaking,” Harris recalled.
Yvonne Williams, the city’s utility supervisor, said she was standing up when the Oct. 10 ’quake hit. “I could feel it rumble,” she said. “Everything was just shaking – the floors, the walls.” Her husband, Gary Williams, told her that pictures hanging on the walls at their home at the southwest edge of Cushing “were knocked cockeyed” and “stuff fell over,” she added.
Mrs. Morehouse said she was sitting in a chair, watching television, when the Oct. 10 quake occurred.
“I felt our house move from left to right, instead of just shaking,” and heard dishes in her china cabinet “banging together,” she said. She and her husband, Woodrow Morehouse, operate an appliance repair business and live one-half mile from Sunnyside School and a mile from the Cimarron private prison.
The earthquakes in the Cushing area began happening about three years ago, Mrs. Morehouse said. Mrs. Williams concurred; “I have lived here all of my life,” she said, and the earthquakes started about the time of the record-setting magnitude-5.7 tremor that struck Prague almost three years ago, on Nov. 6, 2011.
The two earthquakes last week were felt several miles away. Ms. Spotts, who lives near the Payne County Fairgrounds at the eastern edge of Stillwater, said wood trim around the ceiling of her house “pulled away” from the wall, and at least one crack in her house widened.
An earthquake centered 9.3 miles west of Stillwater on Oct. 5 was felt as far away as Logan County. Willie Points of Nicoma Park said he was in his cabin northeast of Luther, reading a book, when “suddenly it felt like something as big as a rhinoceros” struck the cabin about 9 p.m. that evening.
Almost 4,000 ’Quakes in Oklahoma to Date
Records show the Oklahoma Geological Survey logged 3,934 earthquakes in Oklahoma from New Year’s Day through noon Monday – an average of almost 14 tremors each day. Payne County experienced 478 earthquakes during that same 286-day period, OGS records reflect; that total included 25 tremors from Sept. 11 through Oct. 12, and eight of those 25 equaled or surpassed magnitude-3. (See attached chart.)
To put that in perspective, from 1978 to 2008, a period of 30 years, the long-term average earthquake rate statewide was just two magnitude-3.0 or stronger earthquakes per year, the USGS reported in a news release earlier this year.
What has changed is the resurgence of energy production.
Revived Energy Production in Payne County
Payne County has approximately 6,700 oil and gas wells that are designated as active, as well as 221 injection wells, Oklahoma Corporation Commission ledgers indicate. Of the injection wells, six are commercial disposal wells; 74 are enhanced recovery wells, which can include “fracked” wells; and the remainder are all wastewater disposal wells.
The Oklahoma Independent Petroleum Association reports that in some areas, water emerges from the wellbore along with oil and gas. Such wells typically produce 10 times as much water as hydrocarbons, the OIPA claims.
Enhanced recovery is a method of improving production from old zones. “ER is not currently thought by seismologists to be a source of the strong earthquakes we’ve experienced,” said Matt Skinner, the Corporation Commission’s public information manager. “It’s an open, circular process that involves injection, recovery, and injection over and over again,” he explained. “It’s an operation that requires a loop, in and out from the same formation zone to the surface, in constant circulation.”
Disposal wells, though, are another matter. Many geologists and research scientists contend that disposal wells – particularly those accepting large volumes of wastewater, particularly if it’s injected under pressure – have the potential to lubricate subterranean faults, triggering earthquakes.
In 2012, the latest year for which complete records are available, five commercial disposal wells in Payne County accepted 1.28 million barrels (54 million gallons) of saltwater, and 109 non-commercial disposal wells received 24 million barrels (more than a billion gallons) of saltwater. (See attached chart.)
Legislative Meeting Planned Oct. 28
The House Committee on Utility and Environmental Regulation has scheduled an interim legislative study on state monitoring of data arising from wastewater injection wells. That meeting is set for 1-4:30 p.m. Oct. 28 in State Capitol Room 206.
The examination is a consolidation of studies requested by state Rep. Cory Williams, D-Stillwater, and state Rep. Jason Murphey, R-Guthrie.
Murphey proposed a study of injection well data monitoring activities performed by the Corporation Commission, which regulates oil and gas production in Oklahoma. Williams requested a study of the potential subterranean effects of oilfield activity, particularly from “fracking” and high-volume wastewater disposal wells associated with oil and gas production.
USGS Workshop Scheduled Nov. 17-19
In a related matter, a three-day workshop on “Hazard from Induced Seismicity,” co-hosted by the USGS and the OGS, is slated at the Reed Center in Midwest City next month. The workshop “will develop the methodology and models to describe the hazard from induced seismicity,” the USGS reports on its website.
Seismologists and geologists from the USGS, along with academics, industry representatives, engineers, and representatives from state Geological Surveys will meet to “discuss, and hopefully finalize, technical approaches to be used in the USGS National Seismic Hazard maps that include earthquakes thought be induced,” said Robert Williams of the USGS Earthquake Hazards Program, Golden, Colo.
The National Seismic Hazards Map that was released earlier this year did not include earthquakes that are suspected of being induced – manmade – Williams said.
Since the workshop will be “a working, technical meeting focused on probabilistic methods,” the general public is not invited, Williams explained.
Final seismic hazard maps that include manmade earthquakes “won’t be completed until 2015,” he said. Afterward, “the engineering community and the Building Seismic Safety Council will decide whether or not to include them in new building guidelines, which will probably take another year or two” to develop, Williams said.
National Seismic Hazard Maps “affect public safety and influence building and insurance costs,” the USGS says on its home page. Hazard calculations for approximately 10 states, including Oklahoma, “will be affected by taking into account suspected non-tectonic earthquakes.”
Any revisions to the maps could have a significant effect on Oklahoma’s building codes and insurance rates, Jackman noted.
During the USGS workshop, a field trip is planned the afternoon of Nov. 17 to provide an “overview of oil and gas activity in central Oklahoma.” The field trip is to include a tour of disposal wells, including high-volume disposal wells in Oklahoma City.
A daylong session devoted to issues such ground motion, stress and induced seismicity, building codes and case studies is scheduled for Nov. 18. And an internal meeting Nov. 19 will feature discussions among representatives of the USGS, state Geological Surveys and the National Seismic Hazard Maps Steering Committee.
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