Canadian earthquake detector to monitor activity close to Cascadia fault

By Nicola Jones

On June 15, Canada broke ground on its first earthquake early-warning system. Sea-floor sensors will monitor the Cascadia subduction zone off British Columbia to provide crucial seconds of warning if the ‘big one’ hits. Putting sensors so close to the fault should give the Canadian system an edge over a more developed sister project in the United States.

To produce early warnings of quakes, scientists rely on a network of seismometers and accelerometers to detect the tremor’s first, non-destructive primary (P) waves. Those waves travel faster than the destructive secondary (S) waves, and so hit cities seconds to minutes earlier. The closer that detectors are to the source of an earthquake, the more warning they can provide. That time can be used to stop high-speed trains, shut down nuclear reactors and tell the general population to brace for shaking. But with offshore faults, getting close to the action means putting sensors under water, which is very expensive.