An investigation into Tuesday afternoon’s unexplained explosive sounds in north Calgary is underway and Natural Resources Canada is asking for public assistance to help pinpoint the epicenter of the suspected frost quake.

Earthquakes Canada has posted an online survey and is asking for residents of Calgary and surrounding areas to report their experiences from Tuesday afternoon’s seismic activity. The organization hopes the survey results will provide valuable information on Tuesday's incident and frost quakes in general. 

The survey is available at Felt Report Form.

Frost quakes, also known as cryoseisms, are believed to be the result of sudden cracks in frozen soil or rocks caused by expansion as water within the ground freezes.

Questions continue to surround Tuesday’s thunderous sound.

The Calgary Police Service and Calgary Fire Department responded to suspected locations where the sounds of explosion may have originated but their investigations into the sound have not resulted in an explanation for the noise.

Technology has not provided any clarity to the source of the blast. Officials with the University of Calgary say a seismic monitoring station was offline at the time of the incident.