The epicentre is roughly on the same longitude as the Chalk River nuclear facility in Eastern Ontario, about 150 kilometres to the west of the quake. The facility was shut down last November because of concerns about a hypothetical earthquake interrupting its electrical power supply, a move that eventually led to the firing of Linda Keen, Canada's former nuclear safety watchdog. The reactor was officially restarted on Dec. 16 after Ottawa intervened.
The Chalk River facility sits on earthquake fault lines. The area has never experienced a major earthquake, but two minor quakes struck in December, registering 3.0 and 3.6 in magnitude.
Tremours from the earthquake hit three of the country's nuclear plants, but caused no damage. The Canadian Nuclear Safety Commission, the federal watchdog agency, said the quake was felt at the Darlington and Pickering stations in Southern Ontario, and the Gentilly-2 plant in Quebec.
The CNSC said the companies operating the plants, Ontario Power Generation and Hydro-Quebec, have confirmed that the stations weren't affected by the earthquake.
The earthquake shook rooftops in neighbourhoods just west of the capital's downtown core for about 20 seconds. It sounded like a squadron of jet fighters rumbling overhead. "The house and the trees were shaking," said Abela Sama, a nanny working in New Edinburgh who recognized it immediately as a minor earthquake. "I lived in the Philipinnes. There are always earthquakes and so I know how it feels."
Several residents on one residential street in the St. Clair West/Christie area of Toronto emerged from their homes within moments of the quake, which struck at about 1:50 p.m., and immediately began questioning one another about what had just happened.
"The house started shaking," said Michelle Mason. "It felt like there was a subway coming under the house. Dave [her husband]said, `I think that was an earthquake." She said there had been no damage inside.
Across the street, Peppe Tozzo, a 26-year-old musician and yoga instructor came out carrying his guitar, having just rescued a wobbling mirror that was about to fall on his way down the stairs. "The house was just flexing," he said. "I thought it was the wind." Meanwhile, his roommate, 27-year-old Ryan Gillies, was upstairs packing his belongings, and thought the shaking had been caused by a passing truck.
Standing on their porch, both men agreed it was a very strange experience. "I felt like it was a sonic wave from the G-20," joked Mr. Tozzo.
Ottawa paramedics were deluged with 911 calls after the quake, spokesman J.P. Trottier told The Globe. "The city was in a bit of a panic, which is to be expected."
He said there were very few injuries because of the quake. Most of them - minor fractures, scrapes and falls - happened in the packed stairwells of office towers downtown.
"Right now, it looks like very, very low numbers of injuries."
Asked whether he felt the quake, Mr. Trottier laughed: "Oh, yes."
He said he felt pretty secure in spite of the shaking.
"We're lucky enough to work out of a five-year-old,100-year-earthquake-proof building. … I did keep an eye on the ceiling tiles, though."
A Toronto Police spokesperson said that there have been no reports of injuries in Toronto, which was later confirmed by the city in a news release.
"It was shaking enough that my blinds were banging against the window," said James Lorimer, a managing director at Ludwig Financial Recruitment in Toronto, which has its offices on the 37th floor of the office tower at First Canadian Place, the country's tallest office building.
He said his mind flashed to the possibility that there was an incident related to the G-20 or terrorism that was causing the building to rock.
"We had a few conspiracy theories going because the University subway was shut down earlier in the day" because of a suspicious package, he said.
With files from Brodie Fenlon, Ann Hui, Jill Mahoney, Les Perreaux, Kate Allen, Shane Dingman, Dennis Choquette, John Ibbitson, Campbell Clark, Bill Curry, Erin Anderssen, Boyd Erman
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