Through our experience managing pipelines in varied terrains of North America, we are very aware of the effect of the geologic environment on our pipeline infrastructure. Our Natural Hazard Program is one of the key tools for managing the risk to pipeline infrastructure.
While river erosion and, to a lesser extent landslides, are relatively more common events, earthquake-triggered geohazards by contrast are episodic and relatively less frequent, with southwestern BC as the most seismically active region in Canada. Geohazards triggered by earthquakes include ground shaking, vertical settlement and lateral ground displacement.
Earthquakes and Pipelines
Major earthquakes around the world, including recent earthquakes in Alaska, Japan, New Zealand, Peru, Taiwan and Turkey have shown that ground shaking poses a relatively lower likelihood of causing damage to buried transmission pipelines if they are constructed in a manner similar to the Trans Mountain Pipeline. The likelihood of damage to transmission pipelines from vertical ground settlement is also relatively low because these pipelines are relatively straight, with inherent flexibility, and typically do not have complex pipeline geometries that can be susceptible to seismically induced vertical ground displacement.
The most significant earthquake-triggered geohazard the pipeline is exposed to is horizontal ground displacement from landslides and liquefaction induced lateral ground displacement (known as lateral spreading). Understanding potential location, estimated frequency and magnitude of the potential lateral spreading is sought by designers and operators of any infrastructure in seismically active regions.
As with all organizations with infrastructure exposed to seismically triggered geohazards, our objective is to reduce the seismic risks to the Trans Mountain Pipeline. Qualitative assessments of the pipeline and supporting facilities have been completed in seismic-prone areas, and an Earthquake Action Protocol to rapidly prioritize locations for pipeline inspection following an earthquake has been implemented. This also includes procedures for shutting down and isolating the pipeline in the event of a serious earthquake.
At our terminal facilities, the “squat shaped” design of our storage tanks means they are unlikely to topple during seismic activity, and their steel construction makes them flexible enough to absorb earthquake shock waves. Each tank also has containment berms, or bays, which form giant empty pools to collect any spilled oil if a pipefitting were to leak.
We continually review all aspects of our operations and make improvements to incorporate seismic upgrades at our existing facilities.
