Seismic sensors on Ocean Networks Canada’s seafloor observatory installed offshore Vancouver Island detected an earthquake in the Northeast Pacific Ocean on the morning of 24 April 13:56:16 UTC (7:00 a.m. PDT)
The magnitude 6.1 earthquake struck offshore the Haida Gwaii Region, with its epicentre about 280 kilometres south west of Prince Rupert, British Columbia.
Figure 1: ONC Earthquake Sensors and 24 April earthquake epicentre
The Haida Gwaii event was preceded by a magnitude 5.5 earthquake off the coast of Northern California twelve and a half hours earlier. It is unclear whether these earthquakes, occurring about 1300 km away from each other, are in some way related. It is, however, intriguing that the events were located at the southern and northern reaches of the Cascadia subduction zone and that the ONC seismometer at Endeavour detected numerous small local events during the same period of time.
Figure 2. Seismic activity recorded by Endeavour seismometer on 24 April. Each horizontal line represents one hour of vertical ground motion (even hour black; odd hour blue). Bigger earthquakes show as large excursions crossing several rows. Small events right after each fourth hour are caused by electrical interference from the camera that observes hot vent fauna at the Endeavour location.
For more information: Martin Heesemann, ONC senior staff scientist
