Alberta’s Largest Recorded Earthquake was Not Natural, Could Be Caused By Oilsands Wastewater Pumping

Alberta’s largest recorded earthquake in November last year was not natural, new data has revealed. It is said to have most likely been caused by the disposal of oilsands wastewater deep underground. One of the wells located near the earthquake site had been injected with more than one million cubic metres of wastewater down about two kilometres.

A series of earthquakes rocked parts of Alberta in November last year. At the time, it was believed that the earthquakes occurred naturally but now, a closer look at the data has pointed out that they may have been caused by the disposal of oilsands wastewater deep underground. Ryan Schultz, a Canadian seismologist who helped conduct the research while at Stanford University in California said this event was caused by wastewater disposal.

Companies use Oilpatch techniques which include deep disposal wells that inject wastewater kilometres underground. These can cause earthquakes and this is what seems to have happened in Alberta. There is one such well located near the earthquake site that was used to dispose of water used in oilsands operations. Over time, the well has been used to inject more than one million cubic metres of wastewater down about two kilometres.

At the time, it was believed that the centre of the earthquake was about six kilometres deep but a closer look at the data showed that it was four kilometres below the surface, bringing it in range for the oilpatch activity which could have caused the earthquake.

Previously, it was also believed that there are long lag times between deep-well water injection and earthquakes. Schultz pointed out that a previous disposal site in Alberta started quaking three years after pumping began and a Dutch disposal well started causing earthquakes decades after pumping. Alberta’s November earthquakes were clustered right on top of the deep disposal well, he stated.

According to Schultz, the injected water forced itself between the two sides of a fault deep in the earth. That water reduced the friction holding the two sides together which resulted in a slippage that shook the surface.

The researcher believes that these findings could have significant implications for Alberta and Canada’s climate change plans. He added that carbon capture practices that involve pumping large amounts of waste carbon dioxide deep underground can also cause earthquakes.

Vineet Washington