The earth moved! About ten or fifteen minutes ago, a small tremor passed through Toronto. I noticed it because my rack of disk drives started shaking, and making ticking sounds of metal under stress (the rack, not the disk drives)!
Update 1: According to the National Post blog, the tremor was felt as far away as Ottawa, Montreal, and Cleveland. According to the USGS in the same blog post, the magnitude was in the mid 4's.
Update 2: The United States Geological Survey reports on their website that the earthquake occurred at 17:41:41 UTC about 39 km north of Cumberland, ON close to the Ontario/Quebec border. This puts it around 13:41 EDT, with a slight delay before reaching Toronto. At the time, I didn't think to check the system clock on my computer. Knowing the time delay, and determining the distance from Google Maps or Google Earth, we could calculate the propagation speed of the shock wave through (mostly) shield rock. The intensity was magnitude 5.5 [changed to 5.0 on a subsequent viewing] higher than the mid 4's that I reported earlier. The USGS seismometer data also places the epicentre of the quake quite deep -- about 17 kilometers [change to 18].
Update 3: Map of epicentre location:
View Larger Map
Update 4: The Globe and Mail's blog has extensive reporting from all over the province. Various Facebook updates, as well as the verbal report of my son, indicate that offices and classrooms were briefly evacuated - a prudent move in the face of what is described as a "moderate" intensity earthquake. There are reports of a bridge (Barrage McLaren) damaged close to the epicentre, and another bridge near Bowman, PQ, closed. There have been no other damage reports so far as of 17:45, but some government facilities in Ottawa are closed. Ottawa is built on ground which can potentially amplify the effect of an earthquake, and reports (again via Facebook) from friends living there indicate that the intensity was a lot greater for them than for me. Rumours that a tsunami warning was issued for the artificial lake constructed for this week's G20 summit meeting are entirely unfounded [yes, now I am just being silly].