An earthquake shook Greater Victoria just after 4 a.m. Thursday.
It was centred near Sidney and D’Arcy Islands, just east of the Saanich Peninsula and about 11 kilometres from Sidney.
The quake was initially reported as a magnitude-4.1, according the U.S. Geological Survey, but that was later adjusted to 4.0 by the U.S. agency.
Earthquakes Canada reported it as magnitude-3.8 and almost 55 kilometres deep.
John Cassidy, a seismologist with Environment Canada, said those deep quakes are the most common type of damaging earthquake.
(For those wondering why Earthquakes Canada and the USGS often have slightly different data on the same local earthquake, Cassidy said that's because the data is preliminary and subject to updates and Canada's will contain more local data on earthquakes here.)
The Canadian agency said there were no reports of damage, and none were expected. At 55 kilometres deep, even those very near to it were still 55 kilometres away, Cassidy said.
Cassidy said if Thursday's quake was in the magnitude range of 6.8 to 7 like the ones that struck in Washington state in 2001, near Seattle in 1965 and near Olympia in 1949, it would be “one thousand times” the shaking.
"Most people reported either a jolt, like they thought maybe like a truck hit their house or a bit of rumbling they could feel but relatively a short duration," he said. "Others indicated a longer period of shaking, up to 10 seconds, and a few things falling off shelves but for most it was a jolt or thump."
Within minutes, hundreds of people had reported feeling it in Greater Victoria, Duncan, Cowichan Lake and Ladysmith, as well as in the Vancouver area and Washington state.
Earthquakes Canada received reports from people who felt the tremor as far north on the Island as Nanaimo and Parksville.
Karin Hedetniemi, in Ross Bay, said her pup jumped off the bed and woke her up. “A minute later, an earthquake rattled all the dresser handles,” Hedetniemi posted to X.
Victoria author Jean Paetkau said in her post at 4 a.m. she felt “one big shake” in James Bay. “I am awake now.”
Joie Warnock was awake in Fairfield and said “the apartment was swaying, yikes.” Another person posted that she felt it in the Gorge Road area.
The Canadian Earthquake Early Warning system, in effect about a month now, is only triggered by an earthquake with a magnitude of 5.0 larger. The system detects an earthquake immediately after it occurs, and then issues an alert that can give seconds to tens of seconds of warning before the strong shaking starts.
Alerts are sent through the National Public Alerting System and will appear on TV, radio and compatible cellphones.
A magnitude-5.0 earthquake is “when we would expect to see damage,” Cassidy said, and Thursday's earthquake was below that threshold.
Cassidy said the jolt is a reminder that we live in an earthquake zone and that we have small earthquakes every day, earthquakes that are felt every month or so, and larger ones that cause some damage every decade or so.
The temblor comes three weeks before the Great BC ShakeOut earthquake drill on Oct. 17 at 10:17 a.m. The annual event encourages people to drop, cover and hold on as practice in case of an earthquake.
The province's earthquake guide says that if an earthquake hits while you are in bed, you should hold on and stay there, protecting your head with a pillow or blanket. Most injuries occur when people try to run for cover.
More information on earthquake preparedness and what to do in case of a quake is available through the province's earthquake and tsunami preparedness guide.
The Capital Regional District also has information on earthquakes, as do many local governments.
