Chances are you ran out into the street to ask friends and neighbours if they felt it too. Environment Canada initially said the earthquake had a magnitude of 3.9, but upgraded the measurement to 4.1 Friday. Wagstaffe said seismologists will use previous earthquake data to determine what caused Thursday's quake. (CBC Vancouver)Earthquakes are rare for southwestern Ontario because the area sits over a very stable section of the tectonic plate. I mean, it was shallow enough, even though it was a fairly weak earthquake, that a few million people felt weak to light shaking."

Source: CBC News April 20, 2018 12:08 UTC