Marking 20 years
of bold journalism,
reader supported.

The Quake Threat to Dams Posed by Fracking Was Long Warned

A new trove of internal exchanges shaken loose by Ben Parfitt amplifies decades of safety urgings.

Andrew Nikiforuk 10 Jan

Andrew Nikiforuk is an award-winning journalist who has been writing about the energy industry for two decades and is a contributing editor to The Tyee. Find his previous stories here.

“Why is this so difficult?” a BC Hydro dam safety engineer plaintively asked his superiors seven years ago.

He’d been stymied again in proposing that because the risks of earthquakes caused by fracking were clear, preventing disaster required creating “no frack” zones around dams.

His sense of urgency runs through a long thread of discussions within BC Hydro and the Oil and Gas Commission surfaced by investigative researcher Ben Parfitt.

For years now the two crown agencies have been reluctant to publicly talk about the risks earthquakes triggered by the oil and gas industry pose to critical dam infrastructure throughout northeastern B.C.

But a freedom of information request by Parfitt at the Canadian Centre for Policy Alternatives has shed new light on what has been a long and often acrimonious internal debate.

Hundreds of emails, letters, memos and meeting notes released by the utility in response to Parfitt’s request and his just published investigation make the following important revelations:

Officials at BC Hydro have been concerned about the shale gas industry since 2007 when coal bed methane extraction resulted in seismic activity at the Peace Canyon Dam near Hudson Hope.

The Peace Canyon Dam, which provides six per cent of the province’s electricity, is built on fragile shale rock and wasn’t built to withstand even modest earthquakes.

BC Hydro officials warned numerous people in the provincial government, including senior bureaucrats and unidentified ministers, “that fracking near its dams could have grave consequences, including the worst possible outcome—an outright dam failure. Yet its repeated calls for firm no-frack zones near its dams continue to go unanswered,” reveals Parfitt.

After CNRL triggered a 4.5 Magnitude earthquake in November of 2018 that forced the evacuation of the Site C Dam site, its engineers have begun to reassess seismic safety at the dam and to expand on previous studies done prior to its approval.

How fracking causes quakes

The issues are dramatic and will become more significant as fracking and waste water disposal activity increases to support the province’s push for LNG exports to Asia.

In the last decade, as The Tyee has reported in numerous articles since 2011, the petroleum industry has repeatedly broken seismic records in the vast Western Canadian Sedimentary Basin and has caused geologic changes, especially in the Montney shale basin in northeastern B.C.

It has triggered thousands of earthquakes including dozens of significant felt events reaching a magnitude 3 or 4.6.

The primary culprit is fluid injection, including hydraulic fracturing and the injection of toxic waste water deep into the ground.

Fracking blasts significant amounts of water, chemicals and additives into shale rock over short periods, while waste water disposal injects large amounts of water over long periods of time. Both technologies can change pressures along fault lines and cause earthquakes.

The problem for dam engineers is that industry-made quakes behave differently than natural events by causing severe ground motions caused by shallow industry induced quakes.

Earthquakes triggered by hydraulic fracturing can exceed “what the natural hazard was in the first place” explained seismic hazard expert Gail Atkinson to the Tyee in 2015.

In addition they pose real risks to infrastructure only built to withstand natural earthquake hazards. Seismic jolts caused by fluid injection can create more damaging ground motions at lower magnitudes than natural quakes due to their shallowness, explained Atkinson.

The safety engineer who sounded alarms

In compiling a brief chronology of the ongoing debate, largely based on emails and memos exchanged between B.C. Hydro and the OGC from 2009 to 2019 that Parfitt shared with the Tyee, one voice stands out. Scott Gilliss, a dam safety expert based in Hudson Hope issued repeated warnings to superiors which make compelling reading.

“My concern is for the future,” he says in one 2013 email. “Since our province has big hopes for LNG, which would certainly expand hydraulic fracturing operations and injection.”

1976 March: A U.S. study published in Science confirms that “earthquakes may be triggered by increase in fluid pressure” underground.

1990: A report prepared for the US Environmental Protection Agency and the US Geological Survey finds that deep well injection including fracking has triggered documented earthquakes in Colorado, Texas, New York, New Mexico, Nebraska, and Ohio and possibly in Oklahoma, Louisiana, and Mississippi.

1994 June: A Canadian study documents that fluid injection in an oil field outside Fort St John has caused earthquakes as large as Magnitude 4.3.

2009 October: After mapping the occurrence of several earthquakes near Fort St John and Halfway River and others for a 200 km radius around its dams in Peace River, BC Hydro dam safety engineer Scott Gilliss asks himself a question: “Are the clusters of earthquakes being caused by the oil and gas industry?”

Stephen Rigbey, Manager of Dam Safety, replies: “Great Catch. The potential for induced seismicity needs to be addressed at a higher level.”

2009 December: Ray Stewart, director of dam safety for BC Hydro, notifies the province that coal bed methane extraction involving fracking near Hudson Hope may pose “immediate and future risks to BC Hydro’s reservoir, dam and power generation infrastructure.” The risks include induced seismicity, ground subsidence and reactivation of existing faults.

2010 February: BC Hydro reports to the provincial government (the Comptroller of Water Rights which is responsible for dam safety) that a number of reported “felt” seismic events occurred at the Peace Canyon Dam between May and August of 2007. “We hope you find this information useful in your investigations into the effects of the coal bed methane extraction program” taking place near Hudson Hope, B.C.

2010 April: Scott Gilliss notes in an email to his peers that the drilling of coal bed methane wells near the Peace Canyon Dam could pose many different risks including seismic activity and collapse of the ground. “These drilling extraction projects come with too many unknowns for anyone to be able to accurately assess long term impacts and it’s best to keep them away from our dams/reservoirs.”

2010 November: Scott Gilliss again raises more concerns about oil and gas activity in the Peace Region and its impacts on dams. “BCH has to start being proactive to find out…how close the oil and gas drilling and extraction is coming to the reservoir/dams…before it goes too far and becomes a problem.”

2010 November: Gilliss reports to his superiors that two earthquakes occurred about 15 to 25 km northeast of the Bennett Dam as a result of operations by Talisman Energy. “There is potential here for increased seismic activity.”

Stephen Rigbey, manager of dam safety, later informs Gilliss that “your broken record was listened to. This entire issue was discussed at the highest level (Minister to Minister) and was ‘officially’ shut down by out then Director of Dam Safety. Until and unless we see a direct smoking gun…this is a dead issue.”

The OGC tells the Tyee there hasn’t been any links between hydraulic fracturing and “anomalous seismic activity.”

2011 September: Stephen Rigbey, manager of dam safety, reports to colleagues that the Army Corps of Engineers has declared a 3000-foot buffer zone around its dams in most of Texas and several other states where it will not allow new oil and gas drilling.

2011 February: After another company requests permission to draw water from the Williston Reservoir for hydraulic fracking, Scott Gilliss notes in an email to colleagues: “As I have expressed to you, my concerns are related to the overall plans of exploration and development of these shale gas resources” because part of the area being developed “may extend below the WAC Bennet Dam” where there are concerns about seismic stability.

2011 November: Chris Kowalchuk, an engineering geologist at the Site C Dam, reports that the Oil and Gas Commission has informed him that hydraulic fracturing has set off a swarm of 31 earthquakes in the Etcho Field north of Fort Nelson.

Kowalchuk adds that “last year the OGC advised us there was a very low likelihood seismicity induced by fraccing at the Montney and Beryl fields near Site C. “This event hints that this may not be the case.”

2012 August: The OGC admits that hydraulic fracturing has cause scores of “anomalous seismicity” in the Horn River Basin in northeastern B.C.

2012 October: After the OCG finally admits that induced earthquakes have occurred in Farrell Creek, near dams on the Peace River, Scott Gilliss writes in an email: “What a shocker! Are they sleeping or what?”

March 2013: BC Hydro Principal Engineering Scientist Dr Des Hartford informs Scott Gilliss that his concerns about hydraulic fracturing near dams have been heard and that “you have discharged your responsibilities with respect to reporting and management of this matter.”

Hartford adds, “Fundamentally, hydraulic fracturing (‘fracking’) is one of these ‘new and emergent’ threats that require examination in the context of scientific and policy considerations.”

March 2013: Gilliss replies in an email to Hartford that he has gathering a large file on hydraulic fracturing including the case of California’s Baldwin Hill Dam which failed in 1963 due to extensive oil and gas development including fluid injection.

Gillis says that he first noticed new earthquakes being added to the national earthquake database as major fraccing operations began in 2010. “In my view, which I have already shared, the province should simply add buffer zones around any very Extreme and Very High Consequence Dams where hydraulic fracturing cannot be undertaken without a prior full investigation into the risks and an implemented risk management plan. Why is this so difficult?”

December 2013: The OGC introduces a new traffic light system that asks operators to stop fluid injection operations only after they have caused a Magnitude 4 earthquake.

In an email Scott Gillis describes the system as inadequate: “I would question why they are proposing to cease operation only when they exceed M4….Surely it matters what risks there are in a given area. I can’t see us being too happy after a series of M3.9’s felt at a dam, nor would a town be overly impressed.”

2015 August: Malaysian-owned Progress Energy triggers a record 4.6 earthquake north of Fort St. John. It was felt by citizens nearly 100 km away.

2015 December: The OGC releases a report confirming that hydraulic fracturing and waste water injection triggered in the Montney shale 231 tremors between August 2013 and October 2014 alone. The Montney shale basin surrounds three dams in northeastern B.C.

January 2017: Canadian Energy Partners begins a water disposal operation just three km north of the Peace Canyon Dam. This kind of fluid injection can cause major earthquakes.

2017 March: Manager of Dam Safety Stephen Rigbey reports to Stuart Venables, the OGC’s senior petroleum geologist, that the Peace Canyon Dam wasn’t built to withstand significant earthquakes.

“You may find this surprising, but the site was not designed to any particular ground motion. The rule of thumb of the day was to consider 0.1g {peak ground acceleration) in designs….I’ve seen data that show M4-4.5 earthquakes have generated ground motions greater than 0.2g within 10 km of the epicenter.”

Ron Stefik, an OGC supervisor, wrote back: “The seismic tolerance you have noted below is of high concern.” He asked for more engineering reports.

Later that month the OGC suspended disposal activities at the well operated by Canada Energy Partners.

May 2017: Canada Energy Partners contests the suspension of its disposal well before the BC’s Oil and Gas Tribunal.

2017 July: Gail Atkinson, one of the nation’s foremost experts on seismic hazards, recommends a five km “no frack” zone around critical infrastructure as well as 25 km zone where seismic activity is closely monitored.

2017 August: The Oil and Gas Tribunal upholds the suspension of activities at Canada Energy Partner’s well.

December 2017: A few months later the OGC notifies BC Hydro that it will allow Canada Energy Partners to continue fluid injection by the Peace Canyon Dam provided it meets 17 conditions. Emails from BC Hydro employees say the utility was not consulted.

An email by dam safety manager Stephen Rigbey notes that BC Hydro has limited options to restrict oil and gas development that could threaten its infrastructure.

The agency could make an appeal to the Oil and Gas Tribunal “destined to fail” or “initiate a court challenge” or buy out the well at a cost of $5 million.

“We cannot come up with any other alternatives other than ensuring we have strict protocols in place.”

In the same month BC Hydro dam safety engineers meet with OGC to consider ground motion protocols and better coordination on seismograph stations in the region.

January 2017: An inter-office BC Hydro memo strongly disagrees with the decision to re-open the disposal well by the Peace River Dam noting that hydraulic fracturing and water disposal wells can trigger “seismic events of varying magnitiude.” It adds, “The potential for induced seismicity due to operation of the well would impose a new hazard at the Peace Canyon Dam.”

Meanwhile the OGC orders all oil and gas permit holders within 5 km of the WAC Bennett, Peace or Site C dam notify BC Hydro of their fracking and drilling activities.

May 2018: The OGC issues a special project order for operations in the vicinity of Site C that requires permit holders to suspend hydraulic fracturing operations if they trigger a magnitude 3 event and to report events with magnitude 1.5 or greater.

November 2018: A CNRL fracking operation triggers three earthquakes including a Magnitude 4.5 that shakes Fort St John and the work site of the Site C dam. Workers feel a strong initial jolt followed by several smaller shakes and then a larger jolt.

The tremor forces BC Hydro to shut down construction operations and evacuate a cofferdam. Due to an “Unusual Operating Condition” Knight Piesold Consulting recertifies the cofferdams for safety and declares them safe for worker access.

2019 January: Following the 4.5 earthquake that rocked the Site C Dam, Andrew Watson, a design engineer on the Site C project, reports that “there may be some analysis exploring the sensitivity of the response of some of the structures to a range of potential motions” from fracking earthquakes. He notes that current input parameters to study the impacts of earthquakes on Site C dam may not be “suitable to the structures being studied” given the recent the size of the recent quake.

2019 September: The Alberta Energy Regulator issues an order restricting fracking activity near TransAlta’s Brazeau Dam located 55 kilometres southwest of the densely drilled Drayton Valley following a magnitude 4.3 earthquake in the region last March.

The regulator officially banned fracking within five kilometres of the dam site in the deep Duvernay formation, and within three kilometres of the dam site in the shallower formations above the Duvernay.

2019 October: A report written for the BC Oil and Gas Commission says researchers can’t yet answer basic questions about where fracking will trigger earthquakes or why some frack jobs set off only small earthquakes while others trigger larger ones.

The independent geological report by the Calgary firm Enlighten Geoscience finds incomplete seismic data and complex geology are major obstacles to understanding the potential hazard posed by fracking-triggered earthquakes in northeastern B.C.

2019 November: A major U.K. Oil and Gas Authority investigation concludes that it is not possible to predict the timing or severity of tremors caused by the industry. The British government replies by temporarily banning fracking as a threat to public safety.  [Tyee]

Read more: Energy

  • Share:

Get The Tyee's Daily Catch, our free daily newsletter.

Tyee Commenting Guidelines

Comments that violate guidelines risk being deleted, and violations may result in a temporary or permanent user ban. Maintain the spirit of good conversation to stay in the discussion.
*Please note The Tyee is not a forum for spreading misinformation about COVID-19, denying its existence or minimizing its risk to public health.


  • Be thoughtful about how your words may affect the communities you are addressing. Language matters
  • Challenge arguments, not commenters
  • Flag trolls and guideline violations
  • Treat all with respect and curiosity, learn from differences of opinion
  • Verify facts, debunk rumours, point out logical fallacies
  • Add context and background
  • Note typos and reporting blind spots
  • Stay on topic

Do not:

  • Use sexist, classist, racist, homophobic or transphobic language
  • Ridicule, misgender, bully, threaten, name call, troll or wish harm on others
  • Personally attack authors or contributors
  • Spread misinformation or perpetuate conspiracies
  • Libel, defame or publish falsehoods
  • Attempt to guess other commenters’ real-life identities
  • Post links without providing context

Most Popular

Most Commented

Most Emailed


The Barometer

Will the BC Conservatives’ Surge Last?

Take this week's poll