OTTAWA, Oct. 22 (Xinhua) -- Three strong earthquakes in a row have struck off the coast of the Canadian province of British Columbia on Sunday, according to CTV.
There were no immediate reports of casualties or damage from the quakes and no tsunami warning was issued.
All three quakes occurred in the same general area over the course of about an hour, and at a shallow depth of approximately 10 kilometers. A 6.6-magnitude quake struck about 260 kilometers west of Tofino, followed by a 6.8 tremor and then a third measuring 6.5.
Meteorologist and seismologist Johanna Wagstaffe said the earthquakes are a reminder that British Colombia is in a "complicated" tectonic setting.
"Three large ones in a row does seem unusual, and I'm sure scientists will be learning as much as they can over the next couple of days about the change in stresses just off our coast," he added.
British Columbia is located on the Pacific Ring of Fire, an active seismic zone where thousands of mostly small earthquakes are recorded annually by sensors in the province.
Most of the quakes happen near the Cascadia subduction zone, an area where the Juan de Fuca and North American tectonic plates converge, stretching from Vancouver Island to northern California.
An earthquake early-warning system recently tested off the British Colombia coast could give residents anywhere from 20 seconds to two minutes to prepare before a quake.
The first-of-its kind warning sensors developed by Ocean Networks Canada is installed along the Cascadia subduction zone. When fully operational next March, it will be able to estimate the location and magnitude of a mega earthquake.