B.C.’s Oil and Gas Commission says earthquakes that rattled residents of Fort St. John and shook the Site C dam construction site last week were likely caused by fracking or salt water disposal wells operated by Canadian Natural Resources Ltd (CNRL).*
The commission has ordered a 30-day halt to all hydraulic fracturing in a densely drilled region 20 kilometres south of Fort St John.
“This will provide the Commission with sufficient time to conduct a thorough investigation,” said an OGC bulletin. “CNRL’s operations may not continue without the written consent of the Commission,” it added.
On Nov. 30 the industry, which has already changed seismic patterns in the region, triggered three quakes ranging from 3.4 to 4.5 magnitude at three different sites south of Fort St. John.
CNRL, Canada’s largest methane producer, leases more than a million hectares in northeastern B.C. It operates 10 large pads from which it drills and fracks multiple horizontal wells.
The company’s website has released no information on the events.
Local residents described the tremor as a major event felt more than 30 kilometres from Fort St. John.
Liam Strasky, a 21-year-old farmer and carpenter, told The Tyee he was at home in Farmington, about 40 km southeast of Fort St. John, playing Xbox with a friend on the evening of Nov. 30.
“All of a sudden we heard a bang and the house shook violently for five to six seconds,” said Strasky. “We could tell it was a seismic event.”
Twenty to 40 minutes later there was an aftershock, he said. “There were no vertical movements. It just shook the house back and forth a few times.”
Strasky said tremors triggered by the fracking industry also shook the farm house last April and left a crack in the basement
At the time Encana, a major fracker in the re-gion, said it was aware that its operations were linked to “recent examples of anomalous induced seismicity” and “we appreciate this has caused concern.”
The Structural Engineers Association of BC reports that quakes above magnitude 5.0 can cause extensive damage.
Liam Strasky’s father Jim, a long-time grain farmer, said industry “can’t hammer away at these shale formations and not expect something big to happen.” In fracking operations, companies inject large quantities of water, sand and chemicals under the ground at high pressure to crack rock formations and allow oil or gas to flow.
The 53-year-old farmer also noted that “the dams around here don’t like this kind of shaking and I don’t know how they [the authorities] are going to deal with this.”
BC Hydro officials have had concerns since at least 2009 that earthquakes triggered by fracking are a potential risk to its Peace River dams.
Despite a downturn in the industry due to low gas prices, northeastern B.C. now threatens to become a new Oklahoma, where the injection of wastewater from oil production and other industry activities created a swarm of earth-quakes that caused significant damage to homes, roads and public infrastruc-ture.
Regulators shut down many injection wells and reduced the volume in others but it took years to reverse the rising number of earthquakes in that conservative petro state.
A 2017 report on induced seismic activity in northeastern B.C. recorded a total of 355 events with magnitudes of 0.5 to 3.9 between January 2016 and October 2017.
The majority of those events — 244 — occurred in the Montney formation, where industry injects high volumes of pressurized water to crack open dense rock formations and also injects high volumes of toxic salt water produced from these shale formations into disposal wells.
Since 2014 the industry has generated 16 significant quakes with a magnitude greater than 3.0 and as high as 4.6 in the region. The majority have been caused by injection related to fracking.
“The shallow depth of these events can be a controlling factor in the observation of large ground motion amplitudes that can be concerning to the public and infrastructures such as the BC Hydro Site C project,” noted the report.
At an October international conference in Banff on induced seismicity, scientists summed up some of the dramatic research findings on quakes caused by various forms of fluid injection, including fracking.
Bill Ellsworth, a professor of geophysics at Stanford University, told the conference that “induced earthquakes are as strong as tectonic earthquakes.” It doesn’t take much fluid pressure to trigger earthquakes, he said, because “the Earth’s crust is in a near critical failure state everywhere.”
Scientists were also told that the magnitude of an industry-induced earthquake is not the only number to be worried about.
That’s because industry-induced tremors are shallower than natural quakes. As a result, “smaller earthquakes can generate large ground-motion amplitudes due to their shallow depths,” reported Alireza Mahani, a researcher at Geoscience BC.
In his presentation Mahani explained that even 2.5 magnitude quakes can cause damage.
University of Calgary quake expert David Eaton said in one of his talks that we simply don’t know enough to quantify the risk from quakes created by industry.
The Tyee asked Progress Energy (now Petronas Canada) and the Oil and Gas Commission for copies of their presentations at the conference.
Petronas replied that “we did not share printed copies of that presentation for public distribution.”
The OGC, a regulator funded by industry as opposed to taxpayers, has not replied to The Tyee’s request.
The commission has introduced special regulations for the area around Farmington as a result of quakes caused by the industry.
Oil and gas drillers are required to record ground motion and shut down operations when they trigger a magnitude 3.0 earthquake.
But overall, British Columbia has one of the world’s most liberal protocols for tremors caused by the injection of fluids into the Earth’s crust. With the exception of the Farmington area, industry doesn’t have to stop fracking until it has caused a magnitude 4.0 quake.
In England, companies must stop operations if they trigger a 0.5 magnitude quake. In Ohio the threshold is 2.5 magnitude.
*Story clarified Dec. 9 at 10:30 a.m.