The Natural Resources Canada reported a Magnitude 6.6 Earthquake roughly 20 km off the southwest coast of Vancouver Island, British Columbia, at about 8.10 pm local time on Wednesday 23 April 2014 (about 3.10 am on Thursday 24 April, GMT). This is a large quake, and was felt across much of southern British Columbia and northwest Washington State, although there are no reports of any damage or casualties, and no tsunami warning was issued.
The approximate location of the 23 April 2014 Vancouver Island Earthquake. Google Maps.
Vancouver Island is located on the western margin of the North American Plate, close to the Challenger Trench, along which the Explorer and Juan de Fuca Plate are being subducted. These are two remnant parts of the ancient Farallon Plate, which formerly underlay part of the eastern Pacific, and which has now been largely subducted beneath North America. The Explorer an Juan de Fuca Plates pass under the North American Plate as they sink into the Earth, but this is not a smooth process, with the plates constantly sticking together then breaking apart as the tectonic stresses build up.
The subduction of the Juan de Fuca Plate beneath North America. United States Geological Survey.
Witness reports can help geologists to understand the processes going on in Earthquakes and the structures in the rocks that cause them. If you felt this quake you can report it to Natural Resources Canada here.
Follow Sciency Thoughts on Facebook.