First-of-its-kind system to warn of earthquakes

An earthquake early-warning system tested off B.C.’s coast could give residents anywhere from 20 seconds to two minutes to prepare before a quake.

The first-of-its kind warning sensors developed by Ocean Networks Canada are installed along the Cascadia subduction zone and when fully operating next March will be able to estimate location and magnitude of a megathrust earthquake.

Greig Bethel of Ocean Networks Canada, an initiative of the University of Victoria, said the system is active even as more sensors are being installed to increase accuracy. The earlywarning system can help reduce deaths, injuries and property losses, stop bridge and tunnel traffic, open bay doors at fire and ambulance halls, halt landings for incoming air traffic and allow surgeons to stop delicate procedures.

British Columbia is located on the Pacific Ring of Fire, an active seismic zone where thousands of mostly small earthquakes are recorded annually by sensors in the province. Most of the quakes happen near the Cascadia subduction zone, an area where the Juan de Fuca and North American tectonic plates converge, stretching from Vancouver Island to northern California.

Ocean Networks Canada said to maximize warning time, it will focus on setting sensors as close to the Cascadia subduction zone as possible and on minimizing delays in data processing, communication and delivery of warnings. Global Positioning System receivers will be located with the seismic sensors to further refine the magnitude.

Earthquakes release energy that travels through the Earth as seismic waves in two forms — secondary and primary waves.

The primary waves travel faster but the secondary waves are the cause of severe damage and ground shaking. The sensors would detect primary waves to deliver alerts before the arrival of the secondary waves.

“The detection of an earthquake by many sensors can provide rapid estimates of the location and magnitude of an earthquake as it occurs,” said a statement from Ocean Networks. “This information can be used to determine the estimated arrival time and intensity of ground shaking at specific locations across a region, allowing protective actions to take place before the shaking hits.”