A magnitude 4.8 seismic event was detected off the west coast of Vancouver Island just one hour after a tremor with a magnitude of 4.2 struck the Seattle region.

The US Geological Survey says the second quake off Vancouver Island hit at 10:04 pm with an epicentre 161 km southwest of Port Hardy and shallow depth of 10 km.

The first quake to hit the Pacific Northwest this evening occurred at 8:59 pm, with a magnitude of 4.2 struck and had an epicentre just 55 km southwest of downtown Seattle with an extremely shallow depth of just 4 km.

The quake was widely felt in the Seattle region and there were reports it was felt on Vancouver Island but no damage has been reported.

There are no reports of damage from either quake and no tsunami is expected.