The earthquake that rattled Haida Gwaii Saturday has also jolted the debate surrounding the proposed Northern Gateway project, with some saying the quake underlines the potential pitfalls of oil tankers plying the B.C. coast.
That’s despite the fact that neither the pipeline nor the tanker routes outlined in the Enbridge proposal would cross the Queen Charlotte Fault, which runs along the west side of Haida Gwaii and was the seismic backdrop to Saturday’s 7.7-magnitude quake.
“I think we have all been complacent about what happens, or what can potentially happen, with an earthquake,” Haisla Nation Chief Councillor Ellis Ross said Monday.
“We have to think about that in the context of supertankers carrying crude oil in Douglas Channel or outside Hartley Bay or outside Haida Gwaii. ... I think that has to be part of the discussion.”
The Northern Gateway project is physically removed from the area where Saturday’s quake occurred and its design takes geotechnical risks into account, says Enbridge spokesman Todd Nogier.
“This [Queen Charlotte] fault line is well known for its seismic activity, and so we would have taken that into account when putting together our application,” Mr. Nogier said Monday.
And Saturday’s earthquake, despite being Canada’s biggest in more than 60 years, is “well within” standards incorporated into the pipeline design, he added.
In planning the pipeline route, Enbridge avoided crossing active fault lines and tried to skirt land that is or could become unstable.
According to Enbridge documents, extensive work went into avoiding any geotechnical issues such as unstable slopes or rock falls, including rerouting river crossings and tunnelling through a portion of the Coast Mountains.
As well, pipelines and facilities are to meet current seismic standards.
Risks posed to oil tankers from an earthquake-related tsunami would be mitigated by the fact that the Douglas Channel – the route tankers would take to get from Kitimat, B.C., to the open Pacific – is wide and deep, Mr. Nogier said.
The horiztonal, slip-and-slide pattern associated with the Queen Charlotte Fault is less likely to trigger massive tsunamis than vertical movements of the ocean floor, according to earthquake experts.
But any large earthquake can generate localized, small tsunamis by triggering underwater landslides or slumping.
“Any strong shaking – whether it’s beneath the land or beneath the ocean – has the potential to generate significant localized tsunamis,” said John Cassidy, a seismologist with Natural Resources Canada.
The earthquake risk “is a hazard that they have to make sure they are aware of and cognizant of,” said Brent Ward, a geologist at Simon Fraser University.
Pipelines have withstood earthquakes, he added, citing the example of the Trans-Alaska pipeline, which withstood a quake in 2002. But earthquake-related landslides can pose a significant risk.
The proposed $6.5-billion, twin-pipeline Northern Gateway project would carry crude oil from near Edmonton to near Kitimat and condensate in the other direction. Public hearings before a joint review panel – which have included extensive testimony about design, construction and safety issues – are scheduled to resume next month in Prince George.