The largest recorded earthquake in Alberta’s history was likely caused by the disposal of wastewater from oil and gas activity, according to researchers at the Stanford University..A 5.6-magnitude earthquake shook Peace River in northwestern Alberta on Nov. 30, 2022. No injuries or damage was reported, although the tremors were felt more than 400 miles away..Alberta’s energy regulator initially believed the earthquake as a natural tectonic event; however, researchers at Stanford now believe the disposal of wastewater underground to be the main cause of the tremor..The historic study — published March 23, 2023 in Geophysical Research Letters — is the first to link an earthquake of that magnitude to human activity that far away from a mountain range..Operations in Peace River focus on extracting bitumen — a tar-like oil found below the surface — which is injected with hot water to make it easier to extract..Using publicly available information and satellite imagery, researchers were able to assess previous tremors tied to bitumen extraction from the past decade..Satellite imagery showed a 3.4cm uplift in the ground at the time of the earthquake, an elevation change consistent with seismic movement along a previously undocumented fault line. According to the study, the high volume of disposed wastewater increased water pressure on the fault, weakened it, and made it prone to slip..Released only a week after three similar earthquakes less than a mile away from the November tremor, researchers hope it will allow them to gather further information and a greater understanding of how human activity can cause earthquakes.
