A 4.0 magnitude earthquake that struck just after midnight on Tuesday morning was the eighth small quake with a magnitude between 3.8 and 4.7 to strike the region since April 22.
© USGSA swarm of earthquakes struck off Vancouver Island in recent weeks.
"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 that stuck the same area in August 2008 included a magnitude 5.2 quake.
Experts have been warning a 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 a magnitude 6.5 tremor centered that 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.
Another characteristic of subduction zone quakes is their depth. The depth of the epicenter quakes here in California is usually 5 to 10 miles because the San Andreas is a srike-slip fault. Whereas the depth of the epicenter of subduction zone quakes is sometimes as much as 50 miles, so the the area of damage is much wider.
But the places that wiggle a little all the time aren't the scary spots on a moving fault. It's the stuck places along the fault between the moving sections that cause the problems when they finally break loose.
The Cascadia subduction zone has the potential for a 9.0 like the one that hit Japan that would generate large tsunamis, and devastate the entire Pacific basin.