An expert with the University of Calgary says that a seismic monitoring station, which could have shed light on a mysterious explosion in the northwest on Tuesday, was offline at the time.

The loud noise was heard late Tuesday.

Jayden Olszak, who lives in Evanston, says the explosion was very loud. “It shook the house. I called around and a couple of other people heard it. A couple in Ranchlands that heard it, one in Country Hills, and another in Evanston.”

Police and the fire department have investigated, but haven’t turned up anything so far.

ENMAX says there were no gas or power outages and Lafarge says crews were not conducting any controlled detonations in gravel pits.

Military aircraft have also been ruled out.

Dr. David Eaton, with the U of C Earth Sciences department, is looking into the possibilty that it was a frost quake, a task that will be every bit more difficult without the data to back it up.

Frost quakes, also known as cryoseism, may be caused by a sudden cracking action in frozen soil or rock saturated with water or ice.

When water drains into the ground, it may eventually freeze and then expand, putting stress on the surrounding soil or rock.

The stress is then released in a frost quake.

Eaton says that it has been an unusual year for frost quakes in Canada.

A number of other unexplained explosions occurred in Southern Ontario in January.

The people who heard them described them as a loud noise that shook their homes, leading them to believe something had hit their house.

(With files from