Whole lotta shakin', but it wasn't an earthquake
Jan 26 2012
Unusual shaking and rumbling reported around the capital region had people thinking "earthquake" — but, rest assured, there was no seismic event.
Natural Resources Canada responded to public concerns by posting an explanation on its website, saying what was felt could have come from an "atmospheric source", likely sound waves travelling over a long distance.
Taimi Mulder, a seismologist at the Pacific Geoscience Centre in North Saanich, said it received several calls from the public reporting rumbling at about 10:45 a.m. and 2 p.m. Tuesday.
Soundwaves that could create such an event have several possible sources, Mulder said. "We just know it wasn't an earthquake. Jets going at supersonic speed can cause it, a volcano erupting could cause it — anything that puts a loud noise into the atmosphere and generates a soundwave through the atmosphere will do that. It often ends up being the military."
Another possible explanation is that it was a "whistler", in which a thunderstorm in one hemisphere travels via magnetic-field lines to the opposite hemisphere.