Two earthquakes lightly shook parts of Manitoba over the course of one day.

Overnight Wednesday at 4:34 a.m., an earthquake occurred near Spy Hill, Saskatchewan, on the cusp of the Manitoba border. It was a light earthquake of a 4.2 magnitude, according to the USGS National Earthquake Information Center. The closest Manitoba town is Binscarth, a village approximately 15 kilometres west of the earthquake's epicentre. It also could have affected Russell-area residents.  

earthquake(Volcano Discovery)

The second quake occurred the same day, at 8:25 p.m., with a 4.0 rating. It occurred roughly in the same area as the first quake.

Dr. Simon Pattison, the chair of Brandon University's geology department, says many people in the area would have felt these rumblings.

"There were some reports in the immediate area of buildings. homes that were shaking. There were reports of people already in bed and they felt their beds moving around," Pattison says, noting these reports range from light to strong shaking.

Earthquakes in this area are quite rare, maybe once every few years and ones of this magnitude occur once every five to 10 years, on average because of the geological location.

"It's a rare event and certainly piqued my interest."

pattisonGeology professor Simon Pattison says he does not know what caused Wednesday's earthquakes, noting they were stronger and deeper than usual. (Screenshot: Zoom)

Pattison says at first he thought it could have been the results of potash deposits disintegrating in groundwater, but quickly learned that was not the case.

"I started looking at the data so it's like 'oh ok, that's kind of pointing towards something potentially something different, much deeper than the potash deposits," Pattison says. "That got me quite intrigued, and you know somewhat excited because since I've been teaching here at Brandon University I'm not aware of any deeper-seated earthquake that we've had kind of in this region." 

Pattison says this layer is much deeper than his original potash theory. Because of the location on top of a tectonic plate, the prairie regions do not often have many earthquakes, let alone 10 kilometres underground in the "very-old pre-Cambrian basement rock." He says this is all speculation with the data he has, saying these earthquakes do not fit the usual pattern, and the geologist cannot definitely say what caused the earthquakes.