By April 2019 Ocean Networks an organization led by the University of Victoria will deliver to the Government of British Columbia a fully tested system capable of detecting and an earthquake event on the Cascadia subduction fault off the coast of Vancouver Island. The system is based on the placement of eight sophisticated accelerometers on the seabed along the Canadian part of the Cascadia fault. If a megathrust is detected, a packet of data will be sent to end users who will broadcast alerts and take evasive actions as appropriate.
The last catastrophic earthquake on the West Coast of Canada happened January 26, 1700. That event was far worse than the Alaska Earthquake in 1964. The expectation is that if the continental plates off Vancouver Island rupture the event we be more like the earthquake in Japan in 2011. According to scholars, that level of shaking happens on average (over the last 10,000 years) every 550 years, but some of the time periods are as short as 250 years. There are estimates of the probability of having a megathrust that causes serious damage to the West Coast of Canada as 10% in the next 50 years.
The best estimates of the effectiveness of a fully functional early warning system are 90 seconds before the shaking happens. That's enough to duck, cover and hold and turn off dangerous equipment and selected utilities.
Diarmuid D. O'Dea