A magnitude 3.7 earthquake centred near Orillia, Ont., struck just before 11 p.m. Tuesday at a depth of five kilometres, Earthquakes Canada says. The tremor was felt from Kitchener through Toronto to Belleville and Niagara Falls, generating thousands of felt reports, with no damage or injuries reported.
Felt across the region at bedtime
If it felt like the earth moved beneath your feet late Tuesday night, it did — if you were in southern or central Ontario. Earthquakes Canada recorded the magnitude 3.7 quake at 10:59 p.m. ET, with its epicentre about 23 kilometres southeast of Orillia, roughly 99 kilometres northeast of Toronto, at a depth of five kilometres.
The agency’s “Did you feel it?” page collected at least 2,000 reports overnight, and the count continued to climb to more than 2,600 by the following day. Reports came from as far west as Kitchener, through Toronto, east to Belleville and as far south as Niagara Falls, with most people describing weak to moderate shaking — walls rattling, houses groaning, a loud roar or bang in some accounts.
One Beaverton artist, Sarah Cowley, said she heard a loud roaring sound and felt her roughly 120-year-old house shake strongly — while her husband slept through it.
There were no reports of damage or injuries.
Measured differently south of the border
Canadian and American agencies did not land on exactly the same number. The U.S. Geological Survey catalogued the event at magnitude 4.1, locating it about 24 kilometres east-southeast of Orillia at a depth of 8.5 kilometres. Such differences are normal: the agencies use different station networks and location models, and magnitude estimates for small regional quakes routinely vary by a few tenths. Earthquakes Canada, which operates the densest network in the region, put it at 3.7 and five kilometres deep — shallow enough, seismologists note, to make a modest quake feel sharper at the surface.
Why a small quake travels so far
A 3.7 in California might be felt across a few neighbourhoods. In eastern Canada, the same energy can be felt hundreds of kilometres away. The reason is the rock: the ancient, cold and rigid crust of the Canadian Shield transmits seismic waves far more efficiently than the fractured, warmer crust of the West Coast, so shaking decays more slowly with distance. Add a shallow depth and a quiet winter night — much of the region was indoors, in bed, with little ambient noise — and a minor tremor becomes a shared experience for millions of people at once, many of whom posted about it within minutes.
That wide felt area is also scientifically useful. Every “Did you feel it?” submission is a data point that helps seismologists map how shaking spreads through eastern Canadian geology, information that feeds into building codes and hazard maps for cities that rarely think about earthquakes at all.
Rare, but not unheard of
Southern Ontario sits inside the North American tectonic plate rather than on a plate boundary, which makes its earthquakes infrequent and, scientists say, not fully understood. Natural Resources Canada seismologist Marikah Adams said the same area has experienced two earthquakes of similar size in the past 25 years, and that aftershocks from Tuesday’s quake were unlikely.
The region’s benchmark event is far bigger: a magnitude 5.5 earthquake in 1929 remains the strongest recorded in the area. By comparison, Tuesday’s 3.7 was the kind of quake that startles people awake and lights up social media — delivered, this week, in the middle of a stretch of extreme snow and cold — but leaves buildings untouched.
