Earthquake swarm strikes off West Coast again

Experts saya "swarm" of small earthquakes off the northwest coast of Vancouver Island are part of the normal seismic activity in the area, and theycould continue for several more days.

A4.0 magnitude earthquake that struck just after midnight on Tuesday morning was the eighthsmall quakewith a magnitude between 3.8 and 4.7to strikethe region since April 22.

Pacific Geoscience Centre Seismologist Gary Rogers said the activity is focused along a 20-kilometre stretch along an area called the Raveer Delwood Fault, located about 200 kilometres offshore.

"In the very thin crust that we have out there off our west coast of Vancouver Island, it often fractures in a series of small earthquakes, usually about this size being the maximum."

Rogers said more small earthquakes are expected in the area over the next week.

"They often go on for days. There's been a lot of smaller ones, so eventually they'll wind down, but typically, what we've seen in the past is that most of these swarms last a few days to a week or so."

A similar but more powerful swarm thatstruck the same area in August 2008 included a magnitude 5.2 quake.

Experts have been warninga major earthquake hits B.C. every 500 years, and the last one was in 1700. But they said the swarm of small earthquake activity does not indicate a larger earthquake is more likely in the short term.

The last significant quake to rattle the West Coast was amagnitude 6.5 tremor centeredthat struck about 50 kilometres off the west coast of the island in September of 2011,swaying high-rises as far away as Vancouver,Kelowna and Seattle.