“The rate of earthquakes in Oklahoma has increased remarkably since October 2013 – by about 50 percent – significantly increasing the chance for a damaging magnitude 5.5 or greater quake in central Oklahoma.
A new U.S. Geological Survey and Oklahoma Geological Survey analysis found that 145 earthquakes of magnitude 3.0 or greater occurred in Oklahoma from January 2014 (through May 2; see accompanying graphic). The previous annual record, set in 2013, was 109 earthquakes, while the long-term average earthquake rate, from 1978 to 2008, was just two magnitude 3.0 or larger earthquakes per year. Important to people living in central and north-central Oklahoma is that the likelihood of future, damaging earthquakes has increased as a result of the increased number of small and moderate shocks.
Oklahoma’s heightened earthquake activity since 2009 includes 20 magnitude 4.0 to 4.8 quakes, plus the largest earthquake in Oklahoma’s history – a magnitude 5.6 earthquake that occurred near Prague on Nov. 5, 2011. The 2011 Prague earthquake damaged a number of homes and the historic Benedictine Hall at St. Gregory’s University in Shawnee. Prior to the 2011 Prague earthquake, the largest earthquake of Oklahoma’s history was a magnitude 5.5 earthquake that occurred in 1952 near El Reno and damaged state buildings in Oklahoma City.
“While it’s been known for decades that Oklahoma is ‘earthquake country’, we hope that this new advisory of increased hazard will become a crucial consideration in earthquake preparedness for residents, schools and businesses in the area,” said Dr. Bill Leith, Senior Science Advisor for Earthquakes and Geologic Hazards at USGS. “Building owners and government officials should have a special concern for older, unreinforced brick structures, which are vulnerable to serious damage during sufficient shaking.”
USGS statistically analyzed the recent earthquake rate changes and found that they do not seem to be due to typical, random fluctuations in natural seismicity rates. Significant changes in both the background rate of events and earthquake triggers needed to have occurred in order to explain the increases in seismicity, which is not typically observed when modeling natural earthquakes.
The analysis suggests that a likely contributing factor to the increase in earthquakes is triggering by wastewater injected into deep geologic formations. This phenomenon is known as injection-induced seismicity, which has been documented for nearly half a century, with new cases identified recently in Arkansas, Ohio, Texas and Colorado. A recent publication by the USGS suggests that a magnitude 5.0 foreshock to the 2011 Prague, Okla., earthquake was human-induced by fluid injection; that earthquake may have then triggered the mainshock and its aftershocks. OGS studies also indicate that some of the earthquakes in Oklahoma are due to fluid injection. The OGS and USGS continue to study the Prague earthquake sequence in relation to nearby injection activities.
Collaborative USGS and OGS research to understand earthquake rate increase in the central Oklahoma area includes quantifying the changes in earthquake rate, assessing the implications of the increased small and moderate earthquake activity for large earthquake hazards, and evaluating possible links between these earthquakes and wastewater disposal from oil and gas production activities. The OGS is also focused on seismicity in north-central Oklahoma.
To more accurately determine the locations and magnitudes of earthquakes in Oklahoma, the OGS has increased the number of monitoring stations and now operates a seismograph network of 15 permanent stations and 17 temporary stations, many of which are on loan from the USGS. There are also three permanent seismic stations operated by the USGS and the Incorporated Research Institutions for Seismology. Data from this network are shared in real-time with the USGS National Earthquake Information Center, which provides 24×7 reporting on earthquakes worldwide.”
At exactly 10:53 p.m. on Saturday, November 5, 2011, Joe and Mary Reneau were in the bedroom of their whitewashed and brick-trimmed home, a two-story rambler Mary’s dad custom-built 43 years ago. Their property encompasses 440 acres of rolling grasslands in Prague, Oklahoma (population 2,400), located 50 miles east of Oklahoma City. When I arrive at their ranch almost a year later on a bright fall morning, Joe is wearing a short-sleeve shirt and jeans held up by navy blue suspenders, and is wedged into a metal chair on his front stoop sipping black coffee from a heavy mug. His German shepherd, Shotzie, is curled at his feet. Joe greets me with a crushing handshake—he is 200 pounds, silver-haired and 6 feet tall, with thick forearms and meaty hands—and invites me inside. He served in Vietnam, did two tours totaling nine years with the Defense Intelligence Agency, and then, in 1984, retired a lieutenant colonel from the US Army to sell real estate and raise cattle. Today, the livestock are gone and Joe calls himself “semiretired” because “we still cut hay in the summers.”
On that night in November, just as he and Mary were about to slip into bed, there was “a horrendous bang, like an airliner crashing in our backyard,” Joe recalls. Next came 60 seconds of seismic terror. “The dust was flying and we were hanging onto the bed watching the walls go back and forth.” Joe demonstrates by hunching over and gripping the mattress in their bedroom. He points to the bathroom. “The mirror in the vanity exploded as if somebody blew it out with a shotgun.” When the shaking stopped, Joe surveyed the damage. “Every corner of the house was fractured,” he says. The foundation had sunk two inches. But most frightening was what Joe discovered in the living room: “Our 28-foot-tall freestanding chimney had come through the roof.” It had showered jagged debris onto a brown leather sofa positioned in front of their flat-screen TV. Joe shows me the spot. “It’s Mary’s favorite perch. Had she been here…” He chokes up.
The quake baffled seismologists. The only possible culprit was the Wilzetta Fault, a 320-million-year-old rift lurking between Prague and nearby Meeker. “But the Wilzetta was a dead fault that nobody ever worried about,” says Katie Keranen, an assistant professor of geophysics at the University of Oklahoma. We’re driving in her red SUV, just south of the Reneaus’ property, when she stops to point out where the quake tore open a footwide fissure across State Highway 62. The United States Geological Survey (USGS) maintains a database of seismically risky areas. Its assessment of the Wilzetta Fault, Keranen notes, was “zero probability of expected ground motion. This fault is like an extinct volcano. It should never have been active.”
When the Wilzetta mysteriously and violently awakened, Keranen wanted to know why. So she partnered with scientists from the USGS and Columbia University’s Lamont-Doherty Earth Observatory. The morning after the initial foreshock, Keranen’s team scrambled to install three seismometers around Prague. They did so in time to capture the quake system in unprecedented detail. She says, “We got this beautiful image of the fault plane.” Within a week, her team and other scientists had placed a total of 25 devices around the fault zone. One is buried in the Reneaus’ backyard. Now, having completed a yearlong study (just published in the journal Geology), Keranen’s research indicates the Oklahoma earthquakes were likely attributable to underground injection of wastewater derived from “dewatering,” separating crude oil from the soupy brine reaped through a drilling technique that allows previously inaccessible oil to be pumped up. “Pretty much everybody who looks at our data accepts that these events were likely caused by injection,” Keranen concludes.
“We still feel tremors weekly,” complains Joe Reneau. “They rattle our windows.” The couple hasn’t bothered to rehang family photos in their living room. Instead, the framed snapshots are stacked in tidy piles on a coffee table.
“The Wilzetta was a dead fault that nobody ever worried about.” Then the drillers came. And so did a swarm of quakes.
Such seismic activity isn’t normal here. Between 1972 and 2008, the USGS recorded just a few earthquakes a year in Oklahoma. In 2008, there were more than a dozen; nearly 50 occurred in 2009. In 2010, the number exploded to more than 1,000. These so-called “earthquake swarms” are occurring in other places where the ground is not supposed to move. There have been abrupt upticks in both the size and frequency of quakes in Arkansas, Colorado, Ohio, and Texas. Scientists investigating these anomalies are coming to the same conclusion: The quakes are linked to injection wells. Into most of them goes wastewater from hydraulic fracking, while some, as those in Prague, are filled with leftover fluid from dewatering operations.
The impact of fossil fuels is no secret, but until now the short list of dirty energy’s villains never included water. Together, oil and gas extraction and production generate about 878 billion gallons of wastewater annually, roughly what tumbles over Niagara Falls every two weeks. More than a third is injected back into disposal wells. With natural gas production on the rise—it has jumped 26 percent since 2007, chiefly because fracking now makes it economically viable to pursue gas trapped in shale deposits—and unconventional practices such as dewatering ramping up domestic oil development, the wastewater deluge is expected to get worse. Operators are injecting more water than ever into drilling wells, while boring new wells to accommodate the overflow. Yet nobody really knows how all this water will impact faults, or just how big an earthquake it could spawn. In the West, small quakes don’t often cause much damage because of stricter seismic regulations but also because the underground formations—buckled, with younger rock—absorb all but the biggest events. Induced quakes, however, are happening primarily in flatter states, amid more rigid rock, making them more destructive—a stone makes a bigger splash when it’s hurled into a glassy pond than a river of raging whitewater.
For its part, industry is doing its best to avoid discussing the issue publicly, even as its leading professional guild, the Society of Petroleum Engineers, recognized the matter was serious enough to call its first-ever meeting devoted to “injection induced seismicity.” Held in September, the SPE’s 115-member workshop sought to “better understand and mitigate potential risks.” When I reached out to SPE coordinator Amy Chao, she told me, “I appreciate your interest but press is not allowed to attend in any fashion.” My requests to speak with geophysicists at leading oil and gas companies implicated in injection-induced earthquakes were also ignored or denied. I did manage to speak with Jean Antonides, vice president of exploration for New Dominion, which operates one of the wells near the Wilzetta Fault. He informed me that people claiming to know the true source of the Oklahoma quakes are “either lying to your face or they’re idiots.”
Nonetheless, there’s growing concern among state officials. After a spate of quakes linked to injection wells shook northern Arkansas, the state’s oil and gas commission declared a moratorium on underground wastewater disposal activities within a 1,000-square-mile area encompassing the towns of Guy and Greenbrier and required seismic-risk studies in the greater Fayetteville Shale area. Affected residents filed a class-action lawsuit against Chesapeake Energy and BHP Billiton Petroleum—the first time anyone has sued oil and gas companies for causing an earthquake. After an injection well was linked to quakes in Youngstown, Ohio, Gov. John Kasich issued an executive order requiring operators to conduct seismic studies before the state will issue well permits. So far, Ohio is alone in this regard; no other state—or the federal government—requires any type of seismic-risk assessment for all of its injection wells. And that worries scientists: “Nobody is talking to one another about this,” says William Ellsworth, a prominent USGS geophysicist who’s published more than 100 papers on earthquakes. Among other mishaps, Ellsworth worries that a well could pierce an unknown fault “five miles from a nuclear power plant.”
The EPA classifies and regulates underground injection wells—some 700,000 and counting—based on what goes into them. There are six categories. Class VI wells sequester carbon dioxide; Class V wells store nonhazardous fluids; nuclear waste is stashed in Class IV wells; Class III wells are used in mining salt, uranium, copper, and sulfur; industrial chemicals get stored in Class I wells. Wastewater from oil and gas operations is discharged—typically by injecting it under pressure—into Class II wells.
There are at least 155,000 Class II wells in the United States. Of these about 80 percent are involved in recovering hydrocarbons, predominantly through slick-water hydrofracking, a technique developed by Halliburton. Fracking fluid—water blended with lubricants, thickeners, disinfectants, and other compounds—is pumped into well bores at extremely high pressures. Eventually, the fluid reverses course and—along with millions of gallons of salt water that resides underground—ascends to the surface. The “flowback,” now laden with natural gas, is collected, the gas is extracted, and the residual fluid is pumped into disposal wells. There are roughly 40,000 of these, and they can be up to 13,000 feet deep.
The extraction process itself doesn’t generally produce earthquakes. This is because of something known as pore pressure, a measurement of how much stress a fluid exerts into the “pores” of surrounding rock. The whole aim of fracking is to rapidly increase pore pressure just long enough to cleave fissures into sediment and free trapped gas, after which time pore pressure equalizes, easing the subterranean stress. Only rarely is pore pressure high enough in a fracking well to cause an earthquake that can be felt at the surface.
But while fracking wells are intended to withstand high pore pressure, wastewater disposal wells are not. When pore pressure spikes in disposal wells, it can move rock. Disposal wells are drilled into vast, permeable formations—think giant sponges—where there’s plenty of space for water to spread out. But because water is heavy, the more of it that is sluiced into a well, the more it weighs on the rock below. And as Scott Ausbrooks, a geologist with the Arkansas Geological Survey, points out, “Water does not like to be squeezed.” Eventually it finds an escape route, “just like a room of people. The more you put in, the more crowded it gets, and at some point, people are going to start being pushed out the doors.”
Animated GIF: fracked Up?
Drillers inject high-pressure fluids into a hydraulic fracturing well, making slight fissures in the shale that release natural gas. The wastewater that flows back up with the gas is then transported to disposal wells, where it is injected deep into porous rock. Scientists now believe that the pressure and lubrication of that wastewater can cause faults to slip and unleash an earthquake.
With the oil and gas boom generating record amounts of wastewater, these rooms are getting increasingly jam-packed. Exactly how much? The EPA tracks volumes but wouldn’t provide them; agency officials declined numerous requests for interviews. Companies are also pumping into denser rock, or into deeper formations that are inherently unstable. “There’s much more injection going on today where there wasn’t injection before,” says Cliff Frohlich, associate director of the Institute for Geophysics at the University of Texas-Austin, who recently identified a cluster of wells at the Dallas/Fort Worth International Airport as the likely culprit for nearby earthquakes.
Too much wastewater in a disposal well forces liquid downward and outward, he adds. It can meander for months, creeping into unknown faults and prying the rock apart just enough to release pent-up energy. Frohlich describes this as the “air hockey” effect. A puck on an air hockey table won’t move even if the table is tilted upward a few degrees. “It would just sit there,” he says. “But when you turn on the air, it reduces the friction and the puck will slide. There are faults most everywhere. Most of them are stuck, because rock on rock is pretty sticky. But if you pump a fluid in there to reduce the friction, they can slip.”
*It should be noted that the United States Geological Survey used two different techniques to estimate the earthquake magnitude at 5.6. The Global Centroid-Moment-Tensor Project at Lamont-Doherty Earth Observatory of Columbia University used different methods to measure it at 5.7. As Justin Rubinstein of the USGS told us, this type of variance is not unusual, and the measurements are considered consistent.
hat’s exactly what happened in northern Arkansas, where, according to state geologist Ausbrooks, water from several injection wells pushed apart the two sides of a fault, “allowing it to slip and start popping off the earthquakes”—thousands of them. Ausbrooks, along with Stephen Horton, a University of Memphis seismologist, identified the source: a previously unknown seven-mile-long fault that hadn’t budged in modern times. Though not huge, the fault is still long enough to generate a magnitude-6.0 earthquake. (In 1993, when an equal-size temblor hit Klamath Falls, Oregon, it killed two people and caused $7.3 million worth of damage—in a rural area.)
While the largest faults in the United States are documented and mapped—the San Andreas, New Madrid, Cascadia, and dozens of others—”there are faults everywhere, and some are too small to be seen,” explains Mark Zoback, a professor of geophysics at Stanford University who was on the National Academy of Engineering committee that investigated the Deepwater Horizon oil spill. “A fault can be missed that could produce an earthquake large enough to cause some moderate damage.”
Oil and gas companies say they don’t cause quakes but refuse to provide scientists or regulators the data to prove it.
Scarier still is that any fault, no matter how minuscule, can instigate the domino effect scientists have observed during injection-induced earthquakes. “The scenario we worry about is one earthquake spawning another,” says the USGS’s Ellsworth. This phenomenon was evident in Oklahoma, Keranen says, where “we had one fault-plane go, a second one, and then a third one. They ruptured in sequence.” The first tremor in Prague sprang from a minor fault that collided with a larger fault, sparking the quake that trashed Joe and Mary Reneau’s home, along with a dozen others.
How far from the site of an injection well could a quake occur? Scientists aren’t sure. In Arkansas, along the fault discovered by Ausbrooks, tremors emanated nearly 10 miles. Had those quakes collided with another fault, the shaking might have extended much farther. “Once it starts moving, it’s like a chain reaction,” notes Ausbrooks.
All these factors were in play in Youngstown, where D&L Energy Group conducted an experiment, burrowing 200 feet into solid rock known as the Precambrian layer, according to Heidi Hetzel-Evans, spokeswoman for the Ohio Department of Natural Resources. Tremors began three months after wastewater entered the well. The strongest, a 4.0, struck on New Year’s Eve. Wastewater had seeped nearly 2,500 feet beyond the bottom of the borehole into an unknown fault. “There will be no more drilling into Precambrian rock in Ohio,” Hetzel-Evans dryly tells me.
John Armbruster, a seismologist at Lamont-Doherty who was among those summoned to Youngstown, told me, “This well caused these earthquakes. There were no felt earthquakes in Youngstown in 100 years.” Within a year of the well opening, there were “12 felt earthquakes. After the well was shut down, the number decreased dramatically. You’d need Powerball odds for that to be a coincidence.”
There is no shortage of evidence. After quakes struck near Trinidad, Colorado, in 2011, the USGS set up a monitoring network. “A magnitude-5.3 earthquake occurred within two kilometers of two high-volume injection wells,” says Justin Rubinstein, who is part of a new USGS project to study human-induced seismicity. “These earthquakes were caused by fluid injection.” Ditto in Dallas; as UT-Austin’s Frohlich points out, “These earthquakes could have been anywhere. They weren’t. Virtually all of them were near injection wells.”
Earthquakes near Prague, Oklahoma, from November 5, 2011, through December 4, 2011. Red indicates 2.2 magnitude; magenta represents the 5.7-magnitude quake. KellyMcD/Flickr
Ellsworth, who peer-reviewed Keranen’s study, has researched earthquakes for more than 40 years and is a recipient of the Department of the Interior’s highest honor for his contributions to seismology. He studied geophysics at Stanford, earned his doctorate from MIT, and is the former president of the Seismological Society of America. When I asked him if there is any doubt among his colleagues about what produced the quakes in Arkansas, Colorado, Ohio, Oklahoma, and Texas, he replied, “Injection of wastewater into Class II wells has induced earthquakes, including the ones you cite.” Rubinstein agrees: “In my opinion, it’s pretty clear in all of these cases—Youngstown, Arkansas, DFW, Trinidad, and Oklahoma—that injection wells were the cause.”
Does industry concur? Jim Gipson, director of media relations for Chesapeake Energy, operator of the wells under DFW airport and a now-closed well near Greenbrier, Arkansas, declined my request for an interview. Hal Macartney, geoscience adviser for Pioneer Natural Resources, which owns some of the wells implicated in the Colorado quakes, dodged my calls and emails for three weeks. Even those not implicated directly with quake-causing wells are staying silent. Hydrofracking pioneer Norman Warpinski, who works for Halliburton, refused comment. Geophysicist Mark Houston and managing partner Steve Sadoskas, at oilfield-services provider Baker Hughes, wouldn’t talk. Julie Shemeta, founder of MEQ Geo, a firm that does seismic consulting for oil and gas exploration, said she was too busy for a 15-minute phone call even though I offered her a two-month window to schedule it.
I’m not the only one getting rebuffed. There is “a lack of companies cooperating with scientists,” complains seismologist Armbruster. “I was naive and thought companies would work with us. But they are stonewalling us, saying they don’t believe they are causing the quakes.” Admitting guilt could draw lawsuits and lead to new regulation. So it’s no surprise, says Rubinstein, “that industry is going to keep data close to their chest.” When I ask Jean Antonides, New Dominion’s VP of exploration, why the industry is sequestering itself from public inquiry, he replies, “Nobody wants to be the face of this thing.” Plenty of misdeeds are pinned on oil and gas companies; none wants to add earthquakes to the list.
The USGS’s Ellsworth tells me that some operators track seismic data near well sites but won’t share it, and so far there is no state or national regulatory requirement to do so. And the “Halliburton Loophole” written into the 2005 energy bill at the behest of then-Vice President (and former Halliburton CEO) Dick Cheney excludes hydrofrackers from certain EPA regulations, among them provisions related to “the underground injection of fluids…related to oil, gas, or geothermal production activities.” Upshot: “It’s an age where information has exploded, but this is an area where we’re still working in punch cards,” Ellsworth says.
Just knowing the daily volumes of water being pumped into a well would yield critical clues. “There is a correlation that shows the largest earthquakes tend to be associated with the largest volume wells,” adds Ellsworth. Ideally, the USGS would get real-time data. But operators are only required to track monthly volumes, and those tallies are often delayed six months or more. By then, it’s too late. Rubinstein wants “industry to actually give us hourly or daily injection pressures and volume, so we can model where the fluids are going and predict how the stress evolves over time…and be able to come up with some probabilistic sense of how likely you are to generate an earthquake.”
As for Keranen’s explosive research on the Wilzetta Fault, New Dominion’s Antonides is recruiting his own scientists to produce a report challenging it. Meanwhile, he has his own theories. “The traffic driving across the freeway could have caused it,” he says, adding that another “trigger point” is the two large aquifers that bracket the fault. Drought has reduced their water levels, “removing a lot of the weight” and allowing the ground underneath to “rebound” and perhaps release energy in a pent-up fault. “All this stuff is tied together—the aquifers, plus trucks driving across the freeway, plus water disposal, plus 50-story buildings—the whole system of man.” (This hypothesis has some basis in reality. Scientists in Taiwan fear that the weight of a skyscraper unhinged faults underlying Taipei. Though no such structure, it must be said, is found within 50 miles of Prague, Oklahoma.)
Nine days after the New Year’s Eve quake in Youngstown, D&L Energy Group issued a statement that said, “There has been no conclusive link established between our well and the earthquakes. Proximity alone does not prove causation.” In March 2012, state officials published a report explicitly detailing the connection, noting that the recent quakes were “distinct from previous seismic activity in the region because of their proximity to a Class II deep injection well. In fact, all of the events were clustered less than a mile around the well.” But D&L still questions the new findings—even though the quakes petered out soon after the company voluntarily shut down its well.
Ausbrooks and Horton partnered for nearly a year to research the Arkansas earthquakes, driving around the state to install seismometers and collect data. And yet when it came time to publish the results in a leading scholarly journal, Seismological Research Letters, Arkansas Gov. Mike Beebe forced Ausbrooks to remove his name as coauthor. Ausbrooks’ boss at the Arkansas Geological Survey is Bekki White, who did two decades of consulting for the petroleum industry prior to her current post. “Ms. White conferred with our office,” Matt DeCample, a Beebe spokesman, tells me. “We felt that putting the state and/or Mr. Ausbrooks as a coauthor would represent additional academic credentials beyond their usual scope of work. The survey is in the business of data collection, not interpreting that data and reaching conclusions.” When I ask Ausbrooks for a better explanation, he laughs nervously. “Oh, let’s just say, I want to say, but I can’t. I’ll just put it this way: There’s money and politics involved.” (The state collects $14 million in property taxes from Chesapeake Energy alone.)
Fracking is an area where conflicts of interest seem particularly apt to emerge. In December, UT-Austin was forced to retract a much-ballyhooed study showing that fracking didn’t pollute groundwater after Bloomberg News and an independent analysis by the Public Accountability Initiative revealed that the lead author (and former head of the USGS), Charles Groat, had received an undisclosed 10,000 shares a year and an annual fee ($58,500 in 2011) from a fracking company. The head of UT-Austin’s Energy Institute, Raymond Orbach, also stepped down. (Groat is now the head of the Water Institute of the Gulf in Louisiana; Orbach remains at UT.)
Seismologists and geophysicists who work in academia often consult for the oil and gas industry. For example, Stanford’s Zoback is on the board of the Research Partnership to Secure Energy for America, a nonprofit oil and gas advocacy group whose charter is to “effectively deliver hydrocarbons from domestic resources to the citizens of the United States.” Its members include Halliburton, Chevron, BP, and ConocoPhillips. During our conversations, he peppers his answers to my queries with caveats. “People forget that earthquakes are a natural geologic process, and in most of the cases, what the [injection wells] are doing is relieving forces already in the Earth’s crust on faults that would have someday produced an earthquake anyway—maybe thousands of years from now. The oil industry has a history of operating 155,000 [wells] without a problem. Now we have a handful of cases. Without seeming like I’m taking industry’s side, where is the problem?”
Keranen, too, juggles conflicting interests. When we talk, she occasionally cuts herself off mid-sentence and then confesses, apologetically, “I have to be careful what I say.” Her research on the Prague quakes hasn’t been published and she seems concerned it might antagonize those who will decide on her academic tenure. Randy Keller is the chair of the University of Oklahoma’s ConocoPhillips School of Geology and Geophysics. In 2007, the energy behemoth donated $6 million to the university, earning it top billing. Keller is also director of the Oklahoma Geological Survey, which has a mandate to “promote wise use of Oklahoma’s natural resources.” Such alliances make it difficult for him to point fingers. In December 2011, the OGS published an official position statement on induced seismicity, emphasizing that quakes could easily originate through natural dynamics and that “a rush to judgment” would be “harmful to state, public, and industry interests.”
When I emailed Keller in October to inquire whether the OGS had modified its assessment in the face of Keranen’s findings, he replied, “We do feel that the location of these events…the nature of the aftershock sequence, and the focal mechanisms can be explained by a natural event.” A few hours later, he sent me a follow-up. “I wonder if you understand what I was trying to say. We have never flatly said that the injection wells did not trigger the earthquakes. Our opinion is that we do not yet have the data and research results to make a definitive statement about this issue.” Keranen walks the same line, saying that her study will show that wastewater injection “very potentially” roused the Wilzetta Fault. Politics aside, there’s widespread scientific consensus that unregulated wastewater injection presents a serious risk to public safety. “We’re seeing mid-5.0 earthquakes, and they’ve caused significant damage,” Rubinstein says. “We’re beyond nuisance.”
So what would the scientists do? One option is to require operators to check geological records before drilling new wells. The Wilzetta, mapped during Oklahoma’s 1950s oil boom, could have been avoided. Another approach is using high-frequency sound waves to render three-dimensional images of underlying faults—technology that oil and gas companies already employ to hunt for untapped reservoirs. For existing wells, operators could set up seismometers to capture the tremors that often portend larger events. Finally, simply pumping less water into wells might mitigate earthquakes. Horton attempted to test this tactic in Arkansas. “We suggested reducing the amount of fluid they were injecting and continue [seismic] monitoring. We actually submitted a proposal to the industry to do that and they blew us off.” Ohio’s regulations for Class II wells, effective as of October, encompass many of these proposals.
Stanford’s Zoback is not opposed to regulation, so long as it’s not a knee-jerk reaction: “Three things are predictable whenever earthquakes occur that might be caused by fluid injection: The companies involved deny it, the regulators go into a brain freeze because they don’t know what to do, and the press goes into a feeding frenzy because they get to beat up on the oil and gas industry, whether it is responsible or not. While I’m making a joke here, there is currently no framework for scientifically based regulation. Assessing and managing the risk associated with triggered seismicity is a complex issue. The last thing we want to implement is a bunch of new regulations that are well meaning but ineffective and unduly burdensome.”
Getting regulators to agree on new rules is not going to be easy, because the connection between injection wells and earthquakes is inherently circumstantial. Seismologists can’t situate sensors miles underground the instant an earthquake occurs, which means they might never be absolutely certain that wastewater and not natural forces led to the rupture. Frohlich puts it this way: “If you do the statistics, smoking causes lung cancer. But that doesn’t mean that smoking caused your lung cancer.” Ultimately, the courts may decide how much evidence is enough, if the lawsuit in Arkansas goes to trial.
Until then, the Reneaus face more home repairs and an uncertain future. When I leave, Joe walks me out to the driveway. Resurfaced after it buckled in the quake, it’s already showing hairline cracks from recent tremors. Joe blames injection wells but thinks culpability will be hard to come by. “My theory is that even if God came down and said, ‘You oil company guys are at fault,’ they would still deny it. The only thing that’s going to stop this is another big earthquake.”
Why are these mysterious booms being heard so frequently? Maybe not so mysterious, just major earth changes
Why are these so-called “mysterious loud booms” being heard so often around the world?
Once again, mysterious loud booms and shaking are back, this time in Oklahoma, Alaska, Massachusetts, South Carolina, and Indiana, if in fact they ever left.
Maybe, not so mysterious after all, just major earth changes rattling the planet.
Many people know the cause of the mysterious loud booms and shaking. The powers-that-be have known for decades, but for reasons known only to them, they refuse to inform the public, while others who know the truth of what is happening and will tell are often not believed.
So there you have it – the mysterious loud booms continue and the “cause remains unknown.”
Planet X (Nibiru) is stressing Planet Earth. As earth stretches and pulls apart in stretch zones, loud booms are created by the air above the areas slapping together. For example, the continental United States is being diagonally stretched, roughly from San Diego to the Northeast with a bow or curve developing between Alaska and San Diego. The loud booms being heard and the shaking being felt are the result of a tearing or stretching Earth.
When a fault-line moves, you get an earthquake, but when earth pulls apart, you get loud booms and shaking.
For those living in stretch zones and hearing these loud booms, it might be wise to keep a close check on your home and the ground around you for suddenly appearing cracks and sinkholes, and exploding manhole covers, houses, and gas lines.
Oklahoma, Guthrie and Boley (Jan 2-3, 2013): Mysterious booms heard in Guthrie. People living in Guthrie have been reporting mysterious unnerving booms around town. Descriptions are similar. Very loud noticeable booms were heard twice on Wednesday, Jan 2, between 7 and 9 p.m.; some houses shook slightly. On Thursday night Jan 3, a 3.7 quake at a depth of 6 miles rumbled near Boley, Oklahoma in Okfuskee County (VIDEO).
South Central Alaska (Jan 3): Loud booms were reported from Eagle River to Mat-Su Valley between 8 and 10 p.m., buildings and furniture shook. Those hearing the booms agree it was a strong and persistent noise, not sonic booms. A woman living in Peters Creek heard several loud booms and, after about a minute of silence, a rumble that caused her chandelier to shake. Thinking it might have been an earthquake, she checked online, but (of course) nothing was listed for that time – 8:05 p.m.
(Note: As so many are aware, the USGS downgrades or drops earthquakes regularly from its reports and has been doing so for quite some time now. So, we may never know for sure whether the rumbling and shaking felt in Peters Creek was caused by an earthquake. Ask yourself, why would USGS lower quake magnitudes or drop quakes from their reports?)
Massachusetts, Marblehead and Salem (Jan 5): Salem and Marblehead police officers searched for the source of a large boom that prompted a multitude of 911 calls around 1:34 a.m. They were unable to locate a source. One resident reported a loud boom accompanied by a flash of light near Salem State University. This is not the first time loud booms were reported in this area late at night.
South Carolina, Red Bank in Lexington County (Jan 6): For the past two weeks, Red Bank residents have reported loud booms that sometimes rattle windows and are heard either late at night or early in the morning, most recently on Sunday evening, Jan 6. The FAA and the military have confirmed they are not sonic booms, and USC seismologists have no record of seismic activity in the area.
Evansville, Indiana (Jan 6): Loud booms were reported by many in Evansville on Jan 6. Evansville Dispatch received several calls reporting what sounded like a huge explosion. Nothing was found and neither USGS or the Air Force had anything to report.
For those living in stretch zones and hearing these loud booms, remember to keep a close eye on your home and the ground for suddenly appearing cracks and sinkholes and the like. Remember, there are those “in the know” who will not tell you the truth about what is happening, and there are those “in the know” who will tell you an uncomfortable truth and not be believed.
Who should you believe – those “in authority” who say they are sonic booms (often in the middle of the night?), or should you believe your lyin’ eyes and ears? The choice is yours.
Last 14 days of 5.0M and greater showing the area around the Indo-Australia plate breaking apart:
This explains the West Pacific “unrest” that I’ve been showing in all the earthquake updates for the past year+.
The “spillover” effect is occurring at volcanoes, and adjacent plates to the Indo-Australian plate.. causing an uptick in large earthquakes (compensation for the indo-australian plate demise) around the entire planet… specifically the Pacific ring of fire.
All this activity has lead to the North American Craton, Laurentia, to be ‘moved’ from the WEST.. causing pressure to build upon the N. American craton.. thus, we are seeing activity at ANY spot with deep shaft construction — whether it be dormant volcanoes, fracking/injection well/drilling operations, and even some springs/aquifers ! Not to mention areas having major ‘movement’ problems .. like Bayou Corne, Louisiana — salt dome sinkhole collapse.
It all begins to make sense once you understand OUR plate (north american craton laurentia) is being displaced by the Pacific plate… which itself is being displaced by the Indo-Australian plate breaking apart.
To confirm most of these North American sites are indeed what I say they are… Just look up the coordinates of each greater than 2.5M earthquake in North America via http://earth.google.com to confirm .
Tropical Storm Ernesto lashed the Windward Islands with strong winds and heavy rain early this morning, as it passed over St. Lucia near 7 am AST. Ernesto brought sustained winds of 43 mph to Barbados at 7 am AST, and sustained winds of 41 mph, gusting to 63 mph to St. Lucia at 6:15 am AST. Ernesto looks moderately well-organized on Martinique radar, with spiral bands to the north and south feeding into an echo-free center. Ernesto is beginning to show more organization on visible satellite loops, with the very limited heavy thunderstorm activity near its center now expanding, spiral banding increasing, and an upper-level outflow channel developing to the north. Ernesto is fighting moderate wind shear of 10 – 20 knots, and water vapor satellite loops show a large area of dry air to the west. Strong upper level winds from the west are driving this dry air into the core of the storm, disrupting it. It appears, though, that Ernesto has fended off the most serious challenges to its survival, as the pressure has fallen to 1002 mb, and the storm’s appearance on radar and satellite is gradually improving. The latest 7:30 am center report from the Hurricane Hunters also indicated that Ernesto was beginning to build an eyewall.
Figure 1. Radar image of Ernesto at 9:15 am EDT August 3, 2012. Image credit: Meteo France.
Figure 2. Morning satellite image of Ernesto.
Forecast for Ernesto
Ernesto’s survival into today means that the storm now potentially poses a formidable threat to the Western Caribbean. Wind shear is expected to drop to the low range, 5 – 10 knots, later today, and remain low for the next five days, according to the 8 am EDT run of the SHIPS model. With the storm entering a moister environment with increasing heat energy in the ocean, the official NHC forecast of Ernesto reaching hurricane strength by early Monday morning near Jamaica is a reasonable one. The reliable computer models predict a west to west-northwest motion through the Caribbean, with the storm’s heavy rains staying south of Puerto Rico and the Dominican Republic. The more southerly path predicted by the usually reliable ECMWF model, which brings Ernesto to a landfall in Belize on Wednesday, is being weighted less heavily by NHC, since they are assuming Ernesto will stay stronger than the ECMWF model is forecasting. Once Ernesto enters the Central Caribbean on Sunday, the storm’s outer spiral bands will likely cause flooding problems in Southwest Haiti, Jamaica, and the Cayman Islands. Of the major dynamical models NHC uses operationally–the ECMWF, GFS, NOGAPS, UKMET, GFDL, and HWRF–none clearly show Ernesto reaching hurricane strength in the Caribbean. However, some of the best statistical models, such as the LGEM and SHIPS, do show Ernesto becoming a hurricane in the Caribbean. By Monday, a trough of low pressure passing to the storm’s north may be capable of turning Ernesto more to the northwest, resulting in the storm entering the Gulf of Mexico by the middle of next week.
New African tropical disturbance 90L
A strong tropical wave is located just off the coast of Africa, about 175 miles south of the Cape Verde Islands. This disturbance, designated Invest 90L by NHC Friday morning, is headed west-northwest at 10 – 15 mph. Wind shear is a high 20 – 30 knots over 90L, but is expected to drop, and water temperatures are warm enough to support development. NHC gave 90L a 30% chance of developing into a tropical depression by Sunday morning in their 8 am Friday Tropical Weather Outlook.
Kuwait hits 53.6°C (128.5°F): 2nd hottest temperature in Asian history
An extraordinary high temperature of 53.6°C (128.5°F) was recorded in Sulaibya, Kuwait on July 31, the hottest temperature in Kuwait’s history, and the 2nd hottest temperature ever measured in Asia. According to weather records researcher Maximiliano Herrera, Sulaibya is in a location well-suited for recording extreme high temperatures, since high sand dunes surround the site, keeping the wind low and hampering sea breezes from cooling the city. Most record books list the 54°C (129.2°F) recorded on 21 June 1942 in Tirat Zvi Israel as the site of Asia’s all-time maximum temperature, but this record is disputed. The previous second warmest temperature in Asian history was set 53.5°C (128.3°F) at MohenjuDaro, Pakistan on May 26, 2010.
Extreme heat in Oklahoma
The most intense and widespread heat wave in Oklahoma since August, 1936 brought more than half of the state temperatures of 110° or higher for the second consecutive day on Thursday. The temperature at the Oklahoma City airport hit 112°, for the 2nd day in a row. These are the city’s 2nd highest temperatures since record keeping began in 1890. The only hotter day was August 11, 1936, when the temperature hit 113°. Thursday’s temperatures in Oklahoma were generally a degree or two cooler than Wednesday’s, with the hottest temperature reported a 116° reading from a location just south of Tulsa International Airport. The highest reading Thursday at any major airport was a 114° temperature at Tulsa Jones Airport. Oklahoma’s all-time state record is 120°, set in Tipton on June 27, 1994, and at three locations in 1936. Freedom, in the northwest part of the state, hit 121° on Wednesday, but this reading will need to be reviewed to see if the sensor was properly sited.
Sean, rare Mediterranean hybrid, and AK superstorm forms; quakes and tornadoes in OK
Posted by: JeffMasters, 3:52 PM GMT on November 08, 2011
Subtropical Storm Sean formed this morning between Bermuda and the Bahamas. Sean’s formation brings this year’s tally of named storms to eighteen, tying 2011 with 1969 as the 6th busiest Atlantic hurricane season since record keeping began in 1851. Only 2005, 1933, 1995, 1887, and 2010 have had more named storms. However, 2011 has had an unusually low percentage of its named storms reach hurricane strength. We’ve had an average number of hurricanes–six–meaning that only 33% of this year’s named storms have made it to hurricane strength. Normally, 55 – 60% of all named storms intensify to hurricane strength in the Atlantic. There have been three major hurricanes in 2011, which is one above average, and the total Accumulated Cyclone Energy (ACE)–a measure of the destructive potential of this season’s storms–has been about 20% above average. The rare combination of near-record ocean temperatures but unusually dry, stable air over the Atlantic is no doubt at least partially responsible for the unusually high count of named storms, but near-average number of hurricanes and ACE.
Figure 1. The subtropical disturbance that became Subtropical Storm Sean, as seen at 1 pm EST November 7, 2011. Image credit: NASA.
Infrared satellite loops reveal that Sean has developed a respectable amount of heavy thunderstorm activity near its center that is increasing in intensity and areal coverage. While the low-level circulation center is exposed to view, a band of thunderstorms is trying to wrap around and close of the center. If this occurs, more substantial strengthening can occur, since the center will be walled off from the dry air that is currently interfering with development. Bermuda radar shows weak rain bands from Sean rippling across the island, with the strongest rain showers well to the island’s southwest. Sustained winds at the Bermuda airport have been under 30 mph this morning. Sustained winds near tropical storm force were occurring this morning at buoy 41048, about 300 miles west of Bermuda. Winds at the buoy were 38 mph, gusting to 47 mph at 6:50 am EST. Strong upper-level winds out of the west are creating about 20 knots of wind shear over Sean, which is low enough to allow some slow development. Sean is a relatively shallow storm, and the tops of its thunderstorms extend up only to about the 300 mb level. Normally, a tropical storm extends up to about 200 mb. The shallow nature of Sean’s thunderstorms mean that the storm is less vulnerable to wind shear than normal, since the storm is not feeling the strongest winds aloft. Ocean temperatures are near 26.5°C (80°F), which is right at the boundary of being warm enough to support tropical storm formation.
Forecast for Sean
Sean will drift slowly west or northwest today and Wednesday. The latest SHIPS model forecast predicts wind shear will remain about where it is now through Thursday morning, which should allow Sean to slowly intensify to a 50 mph storm. If Sean can make the transition to a fully tropical storm, more significant intensification can occur. The computer models show little or no development of Sean, with none of our reliable models predicting it will become a hurricane. Bermuda is the only land area that need concern itself with Sean, as a trough of low pressure is expected to absorb the storm on Thursday and lift it quickly to the north or northeast. The center of Sean could pass close enough to Bermuda to bring the island heavy rain squalls and sustained winds of 40 – 45 mph on Thursday and Friday. NHC is giving a 28% chance that Bermuda will receive tropical storm-force winds of 39 mph. High wind shear should destroy Sean on Friday.
Figure 2. MODIS image of the hybrid low named “Rolf” in the Mediterranean Sea at 10:30 UTC November 8, 2011. Image credit: NASA.
Unusual tropical storm-like low forms off coast of France
An unusual hybrid low pressure system has formed in the Mediterranean Sea, about 100 miles south of the coast of France. The low began as an extratropical storm named “Rolf”, but has stalled out over the relatively warm waters of the Mediterranean over the past two days, and has acquired tropical characteristics. Heavy thunderstorms have built over the northeast portion of the low, and the storm has a symmetric spiral shape with a cloud-free center, like a tropical storm. The Navy is calling this system Invest 99L. The National Hurricane Center is not responsible for the Mediterranean Sea, so they are not issuing any products for 99L. NOAA’s Satellite and Information Service (NESDIS) is giving 99L a tropical classification based on its satellite presentation, with winds in the 40 – 45 mph range. French radarshows heavy rains from 99L are beginning to affect Southeast France and the island of Corsica. The Lion Buoy, located about 100 miles to the west of the center of 99L, recorded sustained winds of tropical storm force, 40 mph, at 00 UTC yesterday. Water temperatures at the buoy were 17°C (63°F), far below the 26°C threshold usually needed to sustain a tropical storm. The coldest waters I’ve seen a tropical storm form in were 22°C during Hurricane Epsilon of 2005. I doubt that NHC would name this system if they did have responsibility for the Mediterranean, due to the cold water temperatures.
“Rolf” is expected to move slowly northwards into the coast of South France by Wednesday night. Meteo France is predicting heavy rains of 30 – 40 mm/hr (1.2 – 1.6″/hr) will affect the coast Tuesday night through Wednesday, with sustained winds of 50 mph, gusting to 75 mph.
Figure 3. Hybrid subtropical storm of October 8, 1996, off the coast of Italy. According to Reale and Atlas (2001), the storm had characteristics similar to a hurricane, but formed over water of 21.5°C. “The maximum damage due to wind occurred over the Aeolian Islands, at 38.5°N, 15°E, to the northeast of Sicily: assistance for disaster relief was required. Unfortunately, no weather station data were available, but the media reported sheds, roofs and harbor devices destroyed, and houses and electric lines damaged, due to “extremely strong westerly wind.” The perfect agreement between the observations at Ustica, the storm scale, the eye-like feature position and the damages over the Aeolian Island reasonably suggest that the hurricane-level intensity of 32 m/s (72 mph) was reached over the Aeolian Islands.” A similar hybrid low affected Algeria on 9 – 10 November 2001. This storm produced upwards of 270 mm (10.6″) of rain, winds of 33 m/s (74 mph), and killed 737 people near Algeirs, mostly from flooding and mud slides. Image credit:Dundee satellite receiving station.
According to research published by Gaertner et al. (2007), an increase in ocean temperatures of 3°C in the Mediterranean by the end of the century could lead to hurricanes forming there. Miguel Angel Gaertner of the University of Castilla-La Mancha in Toledo, Spain, ran 9 different climate models with resolutions of about 50 km and found that some (but not all) of the models simulated hurricanes in the Mediterranean in September by the end of the century, when ocean temperature could reach 30°C.
Though the Mediterranean may start seeing hurricanes by the end of the century, these storms should be rare and relatively short-lived for three reasons:
1) The Mediterranean is quite far north and is subject to strong wind shear from jet stream activity.
2) The waters are shallow, and have relatively low heat content. There is no deep warm water current like the Gulf Stream.
3) The Mediterranean has a lot of large islands and peninsulas poking into it, increasing the chances that a tropical storm would weaken when it encountered land.
References Meteo France has an interesting animation of the predicted winds and temperatures over the next few days.
Figure 4. Radar reflectivity image from the Tipton, OK tornado of November 7, 2011, showing a classic hook echo.
Shaken and stirred: an earthquake and tornado for Oklahoma
It was a rare multi-natural hazard day for Oklahoma yesterday, as the state experienced both a tornado and an earthquake, six hours apart. The damaging magnitude 5.6 earthquake that shook the state Saturday night spawned amagnitude 4.7 aftershock at 8:46 pm CST yesterday, 44 miles east of Oklahoma City. And at 2:47 pm CST, a tornado touched down in Southwest Oklahoma near Tipton. The tornado destroyed an Oklahoma State University agricultural office, and damaged a hay barn at a dairy farm. No injuries were reported. The UK MailOnline has an interesting article showing the radar image from Saturday’s quake, which captured a massive groups of birds and insects that took flight after the ground shook.
This afternoon, NOAA’s Storm Prediction Center has placed Southeast Oklahoma, East Texas, Southeast Missouri, and most of Arkansas in its “Slight Risk” area for severe weather, thanks to a strong low pressure system moving across the Plains. During the late afternoon, severe thunderstorms with high winds and large hail and expected over the region, and we cannot rule out an isolated tornado.
Bering Sea superstorm targets Alaska
A massive blizzard the National Weather Service is calling one of the most severe Bering Sea storms on record is gathering strength today to the west of Alaska. The storm is expected to “bomb” to a central pressure of 945 – 950 mb Tuesday night, and to 940 mb on Wednesday. These pressures, characteristic of a Category 3 hurricane, will be strong enough to generate sustained winds of Category 1 hurricane force over the waters to the west of Alaska, with winds of 50 – 70 mph expected along portions of the coast. Nome, Alaska is expecting a storm surge of 8 – 10 feet. Waves of 15 – 25 feet with ice on top will batter the shores, causing severe damage to the coast.
Severe weather, including Tornadoes likely on Monday for the South U.S. Plains
Published on November 5, 2011 9:40 am PT
– By TWS Senior Meteorologist
– Edited by Staff Editor
(TheWeatherSpace.com) – A storm system will move out of Southern California through Arizona on Sunday. This system will move eastward and impact Northwest Texas to Western Oklahoma in the form of supercells with a tornado setup developing.
We usually want to wait for these things to get a bit closer for details to run the numbers for the Tornado Risk Model and this seems about the right time to get a ‘general’ idea of the setup
An upper level jet streak will be moving through the New Mexico and Western Texas border on Monday evening. This will provide the needed upper level divergence across the Eastern Texas Panhandle, down to Childress.
This upper level divergence, strong instability, good dewpoint/temp value, low level shear, and even convergence at the surface will make for a severe weather setup, including tornadoes on Monday evening.
This zone will be narrowed down and TheWeatherSpace.com does issue Tornado Watches on this site for viewers that are interested. Those watches appear on the top right of all articles and the main page when issued and one might be needed on Monday should trends continue.
The main threat will be hail, but the Tornado Model numbers indicate a yellow/red value which is good enough for EF1 to EF2 type tornadoes on the south end of the storm system, over and around Childress, Texas.
Oklahoma has been shaken by a series of earthquakes, culminating in a 5.6 magnitude quake that is the state’s biggest on record. Photograph: Jeff J Mitchell/Getty
Earthquakes of up to 5.6 magnitude have shaken Oklahoma, damaging buildings and roads and sending a handful of people to hospital.
The first quake was recorded on Saturday morning at a magnitude of 4.7. The second came on Saturday night and is the largest recorded in Oklahoma, topping a tremor of 5.5 magnitude in 1952, according to the US Geological Survey.
In Prague, Oklahoma, where the first quake was centred, city manager Jim Greff said part of the town library’s ceiling collapsed and a chimney fell through the roof of a home. There were no serious injuries.
The quake buckled highway 62 in three places west of Prague and sent a boulder “about the size of an SUV” tumbling onto a rural road in south-east Lincoln County, said Aaron Bennett, dispatch supervisor for the county’s emergency management division.
The quake was felt more than 300 miles away in Kansas City, where it rattled windows and shook houses for half a minute.
The second quake was a shallow 3.1 miles (5 km) deep and centered four miles east of Sparks, east of Oklahoma City.
JL Gilbert, owner of the Sparks Vineyard and Winery, about four miles from the epicentre of the second quake, said it lasted “a good 30 seconds”.
“It was a pretty good jolt. We’re not used to this. We’re used to being sucked up into the wind,” he said, referring to Oklahoma’s reputation as a tornado alley.
Earthquakes of a 4.0 magnitude east of the Rocky Mountains can typically be felt from up to 60 miles away, according to the USGS. A 5.5 magnitude quake can be felt up to 300 miles from its epicentre.
One of Gilbert’s employees went to the hospital after tripping and hitting his head on a doorway while scrambling to get out of his home, Gilbert said.
Earthquake overview : At 02:12 in the night, the people of the greater Oklahoma City / Tulsa / Prague area have been woken up by a moderate but well felt earthquake. Chances on major damage are almost excluded.
Oklahoma City earthquake November 5 2011 – image courtesy USGS
Update 14:35 UTC : We have added a big load of new I Have Felt It reports.
Update 14:30 UTC : At 08:42 a new 3.4 magnitude aftershock struck exactly the same area.
Update 14:04 UTC : NewsOn6 Oklahomawrites that minor property damage has been reported but no injuries
Update 14:00 UTC : 5 aftershocks occurred since the mainshock, 3 of them greater than a magnitude 3 and well felt by most people.
Update 10:35 UTC : Many people in the epicenter area are reporting fallen objects, mostly objects hanging on walls and standing on cupboards.
Update 10:29 UTC : More aftershocks can be expected later in the night and after daylight, even the coming days. The will rarely reach Magnitude 4 although a stronger earthquake can never be excluded. Stronger aftershocks than mainshocks occur extremely seldom.
Update 09:55 UTC : An earthquake-report.com reader writes : I happen to be in Bartlesville, OK – approximately 50 miles north of Tulsa and I too experienced the earthquake. I was in the midst of checking email when a sort of noise seemed to creep up around me. Odd description, I know, but that’s honestly the best way I can articulate the event as I encountered it. I might have mistaken it for the wind except that it seemed to be coming from all around. It wasn’t until some smaller objects on my dresser began to shimmy and chatter that I felt fairly certain that it was, in fact, an earthquake. Well, that and the expression on Leo, the cat’s face that begged to say, “WTF?!” Good night and safe keeping to all… A lot more testimonies below
Update 09:46 UTC : We are constantly adding I Have Felt It reports which we are still receiving at the moment.
Update 09:45 UTC : The largest earthquake ever recorded in Oklahoma occurred on April 9, 1952 and had a magnitude of 5.5. The second largest was a 5.0 on October 22, 1882.
Update 09:21 UTC : The earthquake epicenter is very close to the Prague Arlington Cemetery.
Update 09:18 UTC : Local TV stations and the fire and police departments were flooded by phone calls from people who reported feeling the quake.
Update 09:15 UTC : So far 3 aftershocks have been registered. The first had a magnitude of 3.4 and the second and third 2.7
Update 09:12 UTC : Some reports indicate that the earthquake has been felt as far as Kansas and North Texas.