Three consecutive earthquakes shook near the boundary between the Pacific and Juan de Fuca plates off of Vancouver Island in the Pacific Ocean Sunday night.

The quakes, said Chris Goldfinger, earthquake geologist at Oregon State University, are "reminders that the whole system is operating and running."

The first quake, reported by the U.S. Geological Survey as magnitude 6.6, hit at 10:39 p.m. Pacific Time, around 120 miles southwest of Port Hardy. Forty minutes later, a 6.8 struck the same area. Six minutes later, the third quake, this one 6.5, was measured in the same area.

No damage was reported, according to CBC News, and there were no immediate tsunami warnings. Four aftershocks between 4.3 and 5.2 magnitude were measured, according to the CBC -- one just before midnight on Sunday and three early Monday morning.

Goldfinger said Monday that the quakes were "slip-strike" earthquakes, happening in the transitional north end of the Juan de Fuca plate.

"The earthquakes are pretty hefty but fairly routine and relatively harmless," Goldfinger said, though he added, "It's kind of unusual actually to have three bigs ones in a row like that."

For people living along the Cascadia subduction zone, worried that three large quakes might be an indication of something to come, he said, these quakes don't have "a direct linkage to Cascadia."

Not that they are completely unconnected.

"These faults are just secondary parts of the same system," he said.

He also said that earthquakes like this can have repercussions along the entire system. If a larger fault is ready to go, Goldfinger said, it could be triggered by seismic waves from a small earthquake somewhere else.

On the other hand, he added, small quakes can act as pressure release valves on a larger system too.

Sunday's activity, he said, "is not a precursor to anything necessarily."

"These are just handy reminders," Goldfinger added, "not to forget" to get ready for the major earthquake that could happen at any time.

-- Lizzy Acker

503-221-8052

lacker@oregonian.com, @lizzzyacker