Earthquake of magnitude 6.4 rumbles southwestern Canada, Vancouver Island

A magnitude 6.4 earthquake shook southwestern Canada near Vancouver on Thursday.

The epicenter of the quake was around 130 miles from Tofino, a small district on Vancouver Island in the Pacific Ocean off Canada's west coast, according to the U.S. Geological Survey . Tofino is around 130 miles west of Vancouver. The quake's depth was around 6.2 miles.

A population of around 2,000 in Tofino would be exposed to light shaking, the Survey said.

The rumbling was first detected just after 8 am local time. Its magnitude was first estimated at 6.5 by the USGS, before it was downgraded to 6.4 minutes later.

Two more earthquakes shook the same area in the next few hours – a magnitude 5.4 temblor came about an hour after and another of magnitude 4.7 hit at around 10:30 local time, USGS reported.

An earthquake of a magnitude more than 6 is considered strong , and could cause damage to "poorly constructed buildings and other structures" up to around 62 miles away, according to the Canadian government .

Dara Goldberg, a research geophysicist for USGS, said "well over 100" magnitude 6 earthquakes are recorded annually.

The USGS said there was no risk of a tsunami following the quake.

The quake comes less than a week after a magnitude 5 earthquake struck the same area on Friday morning. The earlier earthquake also centered in the Pacific Ocean off Canada's coastline, nearly 150 miles from Tofino, and had the same recorded depth.

Goldberg said the latest series of quakes happened where the Pacific Plate and the Juan de Fuca Plate meet. "If you have two tectonic plates meeting, it's always more prone to earthquakes than, say, the middle of the continent," she said.

Earthquakes also often happen in sequences, she said. "You have these stresses, these pressures that build up at the boundary between two tectonic plates," she said. An earthquake happens "when part of it slips, when it slides one plate against the other."

A magnitude 6.4 earthquake, which is moderately sized, could trigger smaller earthquakes "popping off along the edges," she said.

This article originally appeared on USA TODAY: Earthquake of magnitude 6.4 rumbles southwestern Canada, Vancouver Island