A powerful magnitude 7.7 earthquake struck central Moresby Island in the Haida Gwaii archipelago at 8:04PM PDT, 27 October 2012. Residents along the west coast—from Alaska to Vancouver—also felt several aftershocks up to magnitude 5.8. However, no major damage or injuries were reported. This was the largest temblor to hit Canada since 1949, when an 8.1-magnitude quake hit west of the Queen Charlotte Islands, in the same area.

The following plots show both seismic and bottom pressure data collected by Ocean Networks Canada...