A “boom” heard and felt by area residents on Saturday evening may not have been a naturally occurring earthquake.
According to Natural Resources Canada, seismic activity took place at 6:37 p.m., measuring 1.5 in magnitude at depth of five kilometres, 29 km north of Fort Frances.
It is possible, however, that this seismic activity was not an earthquake but a blast in relation to work being done for a road project at Stanjikoming FN.
“Blasts, for example associated with mining activity, do often show up on our seismographs,” said Natural Resources Canada seismologist Cathy Woodgold told the Times yesterday.
“The signals are somewhat similar to earthquake signals although there are usually some differences which help distinguish them,” she added.
Fellow seismologist John Adams said this rather small event was felt by many people, and Natural Resources Canada would like to know for certain whether it was a natural earthquake or an explosion or blast.
“This will allow us to flag it in the database so we can reliably calculate the rate of natural earthquakes used for the calculation of seismic hazard across Canada,” he noted.
“Also if we know the geographic location of the event we can re-examine our readings from the seismometers and hopefully reconcile the readings and the confirmed location,” added Adams.
Adams also said if it was a natural event, Natural Resources Canada’s location at 48.86N 93.41W places it rather a distance from the felt reports—a larger distance than the common location error for moderate earthquakes.
“If we get confirmation that the felt area is small and away from the current location we have we’ll look to see if we misidentified the readings from the seismometers,” noted Adams.
He added most earthquakes of magnitude less than two go unnoticed by people.
Fort Frances is in an area of very low seismicity, one of the lowest in Canada, said Adams.
To report details of the event, Adams directed the public to: www.earthquakescanada.nrcan.gc.ca/dyfi-lavr/known-connu-eng.php
As of press time today, the Times has been unable to officially confirm whether blasting took place at 6:37 p.m. on Saturday.
Several attempts to contact George Armstrong Co. Ltd., the contractor working on the road project, have been unsuccessful as of press time today.