The earthquakes that rattled Fort St John last Thursday evening were not natural phenomena.
The quake, which shook up an area south of the city, was likely caused by energy companies’ massive fracking of one of the many wells in the region.
B.C.’s Oil and Gas Commission (OGC) ordered one or more operators to stop drilling and says more details will be forthcoming.
Hydraulic fracturing injects large volumes of water, chemicals and sand into the ground to shatter rock formations several kilometres beneath the surface. The fractures, once propped open with sand, allow oil, gas or natural gas liquids to flow.
The industry currently has no way of telling how these induced fractures will behave or if they will connect with natural faults in the rock formations.
The latest quake occurred at the same depth that industry is fracking shale rock, about two to three kilometres from the surface, said Honn Kao, the leader of induced seismicity research project at Natural Resources Canada in Victoria, B.C.
“Based on this information the OGC and Natural Resources Canada concluded that there is a very high chance the earthquake was induced by injection operations nearby,” Kao told The Tyee.
The tremor and accompanying aftershocks shook houses in Fort St. John, Charlie Lake, Taylor, Chetwynd, Dawson Creek and Hudson’s Hope reported the Alaska Highway News.
It was also felt at the construction site of the Site C dam.
Almost 300 local residents submitted “felt” forms to Natural Resources Canada on the extent of the shaking and damage. An hour after the 4.5 magnitude quake a magnitude 4.0 tremor, also likely caused by the oil and gas industry, shook a region 26 kilometres southeast of the city.
Research scientists have found hydraulic fracturing and related activities have changed seismic patterns in both northeastern B.C. and northwestern Alberta over the last six years.
Ever-growing injection volumes, uncharted faults and over-pressured shale formations have all played a role in the explosion of industry-made quakes.
According to presentations by the OGC, industry-made earthquakes can pose a hazard to roads, pipelines, dams, groundwater and public safety.
Between 2013 and 2015 the fracking industry has likely caused more than 700 seismic events in western Alberta, according to a report from the TransAlta/Nanometrics monitoring network.
In the last six years thousands of small tremors and scores of significant quakes in northeastern B.C. have prompted increased seismic monitoring and research.
Between 2014 and 2015, Progress Energy, for example, triggered almost 700 seismic events, including a 4.6 magnitude tremor on Aug. 17, 2015 that could be felt almost 180 kilometres from the epicentre.
Progress had injected more than 160,000 cubic metres of water, chemicals and sand over a three-week period, triggering the large quake. A magnitude 5.0 tremor can cause significant damage to property.
Companies actively fracking shale formations in the Montney formation in northeastern B.C., largely to retrieve natural gas liquids, include Progress Energy (now Petronas Canada) ARC Resources, Chinook, Crew, Encana, Tourmaline, ConocoPhillips and Shell.
According to recent studies, approximately 5,500 multistage hydraulically fractured horizontal wells have caused 165 earthquakes greater than magnitude 2.5 in the Montney formation between 2009 and 2016, and thousands of lesser quakes.
The number of wells — and earthquakes — will likely increase when the recently approved LNG Canada project is completed.
In Alberta’s Duvernay formation industry has unsettled the community of Fox Creek, with more than 63 quakes greater than magnitude 2.5 over the same time period with just 374 wells.
A series of micro-earthquakes in 2013 evolved into higher magnitude earthquakes three years later, peaking with a 4.8 magnitude event in 2016 that alarmed residents and seismic researchers.
Fracking and the injection of wastewater have been responsible for increased seismic activity in Ohio, England, Arkansas, Texas and Oklahoma.
Energy regulators have responded to the earthquake swarms caused by fluid injection with so-called traffic light system.
It was first developed in El Salvador in 2006 at a geothermal operation to help control earthquakes caused by the injection of water into hot fractured rocks at the base of a volcano.
With a green light, operators could inject water into the ground. If tremors reached the point of damaging buildings, a red light signalled the operators to stop.
Various jurisdictions, including B.C., have adopted different versions of the system in response to earthquakes triggered by fracking.
In Ohio, for example, fracking operators must directly communicate with the energy regulator as soon as they have triggered a magnitude 1.5 quake. A 2.5 quake leads to temporary stoppage and modification of injection volumes or rates.
But Alberta’s stop light system doesn’t require action until there is an earthquake greater than magnitude 2.0. Once a fracking or water injection operation has caused a magnitude 4.0 earthquake or greater, industry must temporarily shut down operations.
In contrast, B.C. only has a “stop light system,” explained Kao.
Drillers don’t have to cease operations until they have triggered a magnitude 4.0 or greater quake within three kilometres of their well site.
In the case of the recent Fort St John quake, operators ceased their fracking operations and the protocol did its job, said Kao.
But his research has found a prominent weakness in the system.
In two cases significant earthquakes triggered by fracking occurred well after the fluids were injected.
So-called “delayed triggering” can be a problem for the effectiveness of the traffic light system, warned Kao.
At a recent conference on industry-made quakes, Gail Atkinson, a Canadian seismic hazard expert, laid out a list of growing uncertainties and unanswered questions.
“What is the hazard potential of small to moderate… very shallow events?” asked Atkinson, who has recommended a five-kilometre exclusion zone around dams and extensive monitoring within 25 kilometres to protect infrastructure from industry-triggered earthquakes.
“Is there a minimum magnitude for damage?”
“How do we decide what is an acceptable increased ground-motion hazard for critical infrastructure, and what mitigation is reasonable? Who decides? What if we/they get it wrong?”
Seismic researchers can’t answer any of those questions yet.
Story updated on Dec. 5, 2018 at 10:25 a.m.
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