Regulator says drilling likely triggered 4.4 temblor
Hydraulic fracturing, a technology used to crack open difficult oil and gas formations, appears to have set off a swarm of earthquakes near Fox Creek, Alberta, including a record-breaking tremor with a felt magnitude of 4.4 last week.
That would likely make it the largest felt earthquake ever caused by fracking, a development that experts swore couldn’t happen a few years ago.
Fracking operations in British Columbia’s Montney shale generated similar seismic activity of that magnitude last year, and earthquake scientists at Ontario’s Western University are still analyzing the two events to see which is the largest.
“The location of the earthquake is consistent with being induced by hydraulic fracturing operations,” confirmed Peter Murchland, a spokesman for the Alberta Energy Regulator.
“The AER regards all changes in seismicity that have the potential to indicate an increased risk associated with hydrocarbon production seriously,” Murchland added.
Jeffrey Gu, a physics professor at the University of Alberta, said the Alberta Geological Survey and other agencies were investigating the Fox Creek swarm, which hit about 260 kilometres northwest of Edmonton. But Gu said he could not disclose their findings at this time. He offered no details on the scale or scope of the investigation.
Alberta experienced more than 400 small earthquakes between 1985 and 2010. But according to the Alberta Geological Survey, felt earthquakes are uncommon. “There have been fewer than 15 catalogued events greater than magnitude 3.5 since 1985,” it has stated.
For years industry and fracking experts argued the technology wouldn’t cause quakes that could be felt on the surface.
But specialists in earthquake hazards such as Gail Atkinson, who holds the Canada Research Chair in Induced Seismicity Hazards at Ontario’s Western University, argued the opposite.
“I have consistently maintained this kind of thing can happen,” said Atkinson. “With fracking, the magnitudes have been increasing every year.”
Natural Resources Canada reported a swarm of at least 15 earthquakes this January west of Fox Creek in a region where Encana, Talisman, Apache, Chevron Canada and ExxonMobile intensified the drilling and fracking of two-kilometre-long horizontal wells nearly a year ago.
The companies are cracking rock in the unconventional Duvernay shale at a depth of 3,000 metres in order to extract condensates, a product typically worth more than oil and used to dilute heavy bitumen for pipeline transport.
An investigation by Atkinson last year into a related swarm of 25 small earthquakes in the same area ranging in magnitude from 2.5 to 3.5 between 2013 and 2014 found that the events also corresponded “closely to hydraulic fracture treatments of oil and gas production wells in the immediate vicinity.”
Last Friday’s shaker
Since Dec. 2014, a second swarm of earthquakes has rattled the region within a 50-kilometre radius of the community of Fox Creek, an oil and gas town with a population of 2,000 people in northern Alberta. The community is about 260 kilometres north of Edmonton.
The largest Fox Creek quake registered 4.4 magnitude and caused walls to shake and beds to move. It became the source of constant social chatter on Friday, Jan. 23.
“When we hit a magnitude of 3.8 this month, I’d thought for sure that the industry would stop and take a smoke break to figure out what’s going on,” said 57-year-old Barb Ryan, a Fox Creek resident who has been keeping an eye on resource development. “But they didn’t. Many are in denial here.”
Ryan has pressed for more transparent monitoring over the fracking industry’s growing impacts on water, air and public health, but said she has faced resistance from local authorities. (She also graphed the Fox Creek swarms using coordinates from Natural Resources Canada.)
The earthquakes have mostly taken place in the province’s first “play based regulation pilot,”a geographical area where the regulator has given blanket approval to the development of the formation as opposed to approving one well at a time. The Alberta Energy Regulator says the strategy “results in regulatory efficiencies,” but critics call it a new form of deregulation.
Ryan said that most people in Fox Creek know little to nothing about the first or second earthquake swarm, because there has been no public reporting on the events.
To recognize the risk of earthquake hazards in Alberta might put livelihoods on the line and businesses at risk, she said. “Cognitive dissonance prevents some communities from admitting or even discussing the resource industry’s impacts. The topic is very divisive.”
Many Alberta geologists did not answer Tyee queries on the earthquake swarms.
Based on public data from Natural Resources Canada, Ryan estimates the region around Fox Creek has recorded approximately 94 small quakes since 1990.
“We’ve had more than 70 of those quakes since Dec. 2013,” she said. “We once averaged zero to three quakes a year. Since the initial swarm, we’ve averaged zero to four quakes a day.”
Rise of ‘man-made’ quakes
Overwhelming scientific evidence from the U.S. Geological Survey now shows that the fracking industry and its need for huge wastewater disposal wells have fostered unprecedented “man-made earthquakes” in the eastern and central U.S. In the process the industry has rewritten seismic records in Ohio, Oklahoma, Colorado, Kansas, Arkansas and Texas.
Some experts now argue that man-made industry quakes are more dangerous than natural ones. Western University’s Atkinson said that “the hazards may be significant, depending on the proximity of infrastructure, and should be carefully evaluated… the hazard is concentrated close to the activity [within about five kilometres], because the motions die off with distance.”
Added Atkinson: “The earthquake hazard from induced seismicity in places like Alberta where seismicity is being triggered is greater than the natural earthquake hazard… it will take regulators in the United States and Canada a while to figure this out.”
Experimental frack operations typically require up to 18,000 horsepower to pump 18,000 barrels of water and between 100 and 165 tonnes of rock crack openers, sand or “proppants” as many as 40 times to create fractures along one lateral well.
Alarmed by the industry’s ability to trigger earthquakes, regulators in B.C. and Colorado recently introduced a seismic traffic system. Whenever fracking operations or injection wells activate felt earthquakes greater than a magnitude of 4.0, operations must shut down to prevent more serious shaking.
Alberta has no such policy. Operations that currently generate earthquake swarms can do so with impunity, though that may soon change, according to a spokesman for the province’s energy regulator.
“The AER is developing a scientifically-based protocol for addressing anomalous seismicity that is appropriate for Alberta,” Murchland said.
At one time, industry experts and lobbyists maintained that “seismic activity caused by hydraulic fracturing is not a hazard or nuisance.”
But the complexity of geology has confounded the industry. While inducing micro-earthquakes to open rock pores, a frack job perturbs the stress of the rock. Injected fluids can then find faults and cause slips, resulting in earthquakes.
“We don’t know the magnitude limits for these earthquakes or how big an event can get,” said Atkinson, who has analyzed seismic hazards for dams, buildings and offshore platforms.
“We also don’t know if we can predict in advance the likelihood of triggering such an event, either. And we don’t know if we can image the faults before fracking and avoid them, or how they’ll behave if we hit them.”
Injections reactivate faults: experts
The Alberta Energy Regulator told The Tyee that it is also investigating another swarm of earthquakes that shook up Cardston, Alberta. That incident “was likely induced by hydraulic fracturing,” a spokesperson said.
In 2012, as many as four earthquakes rattled an area near the Blood Indian Reserve, or Kainai Nation. The tremors ranged from 2.4 to 2.7 in magnitude according to data captured by the U.S. Geological Survey in Montana. It shook homes on the reserve where many residents remain opposed to fracking. The province has yet to issue a report on the earthquake swarm.
Injecting fluids into shales to create fractures can create a chaotic and uncontrollable network of cracks that can connect to fault zones. The reactivation of these faults can then trigger an earthquake, scientists say.
The disposal of toxic wastewater extracted from fracking jobs into deep formations can also cause swarms of earthquakes by the same mechanism.
Injection wells, with names like King Kong and Deep Throat, can trigger earthquakes up to 20 kilometres away. The wells may inject more than 150,000 barrels of waste into the ground a month. Years may pass before the fluids migrate or change rock pressure, activating nearby faults and fractures.
Between 2010 and 2013, the U.S. Midwest, home to extensive fracking, has experienced more than 100 induced and felt earthquakes over a magnitude of 3.0 per year, compared to the normal average of 21.
Oklahoma, once a seismically quiet region, has now become the most earthquake prone jurisdiction in the Lower 48 due to fracking and the injection of its associated wastewater. It now records more earthquake activity than California.
Due to a 50 per cent increase of quakes greater than a magnitude of 3.0, the U.S. Geological Survey issued residents of the state an unprecedented advisory last year: prepare for “increased hazard” from industry-made quakes.
“Building owners and government officials should have a special concern for older, unreinforced brick structures, which are vulnerable to serious damage during sufficient shaking,” said the warning.
The earthquake swarms have produced lawsuits in Oklahoma, Texas and Arkansas alleging that oil and gas companies are responsible for making earthquakes that have caused property damage and personal injury. In Oklahoma, there has been a rush on earthquake insurance.
Due to growing concerns about public health, groundwater contamination and man-made earthquakes, New York state banned the mining of shale basins last year. The governments of the Yukon, New Brunswick, Newfoundland and Labrador and Nova Scotia have placed moratoriums on the technology. A new group in Prince Edward Island is calling for a complete ban.
BC frack quake monitor hired
Industry-made quakes in northern B.C. have become such an ongoing concern that the Induced Seismicity Monitoring Network Consortium, which represents government, industry and regulators, recently hired a seismologist for two years.
The earthquake hazard expert will “monitor induced seismicity from natural gas development in northeast B.C. and study the relationship between fluid injection and potential large-magnitude seismic events.”
To date, B.C. fracking operations have tried to avoid faults by reducing frack stages, or using less proppant to keep cracks open, but to no avail. “The success of these mitigation measures is difficult to ascertain,” stated the B.C. Oil and Gas Commission in its latest earthquake report.
Unlike other geological agencies on the continent, the Alberta Geological Survey, an arm of the industry-funded Alberta Energy Regulator, does not report on induced seismicity in a timely fashion. There is little data available from 2010 to 2014 when hydraulic fracturing took off in the province.
Residents north of Cochrane claim that seismic activity caused by the fracking of the Cardium oil formation not only cracked foundations and broke windows, but has not been properly investigated.
When a possible earthquake uplifted Ann Craft’s mobile home in 2012 during the fracking of four shallow coal bed methane wells, the province agreed to do a study and then reneged on its promise.
Members of the Alberta Geological Survey say that provincial seismic monitoring is inadequate: “[It] is likely that network coverage in the Western Canadian Sedimentary Basin is too sparse to consistently detect” small events caused by injection wells, land subsidence or hydraulic fracturing, said one recent study.
A 2014 report by the Alberta Energy Regulator concluded that the risk of industry-caused earthquakes was low, but added that its monitoring capacity was not up to the task: “[I]f it becomes necessary to verify or refute a definitive causal correlation, it would be hard to do so with the currently available data. In the areas of concern, more work is needed to expand the array of seismic stations to precisely detect the epicentre and hypocenters of an earthquake.”
‘Minor anomalous seismicity’: CAPP
The Canadian Association of Petroleum Producers describes hydraulic fracturing as a “safe and proven” technology to extract natural gas and oil, even though one recent Alberta fracturing incident broke cap rock and released nearly 12,000 barrels of bitumen into aquifers and the boreal forest at a Canadian Natural Resources Ltd. operation.
But CAPP adds that “certain oil and gas basins, such as the Horn River Basin of British Columbia, have a distinctive geology, and hydraulic fracturing has caused rare and minor anomalous seismicity.”
Earthquake hazard scientists argue the industry has routinely underestimated the complexity of geology for unconventional hydrocarbons everywhere, and is now encountering unknown faults and triggering earthquake swarms by negligent design.
In Australia, one group of scientists at Southern Cross University recently argued that the fracking industry has moved as fast as a hare, while public policy and good baseline science has proceeded with the pace of a tortoise.
By Andrew Nikiforuk from The Tyee on Jan. 29, 2015.