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 2020 TheTyee.ca

“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.”

...continued in PART TWO