Scientists monitoring for megathrust earthquakes with new sensors off Vancouver Island

The pioneering system will monitor movement along the Juan de Fuca and North American plates that carry the threat of triggering an earthquake of magnitude of eight or greater. (Ocean Networks Canada)

Ocean Networks Canada (ONC) has established a new tectonic movement monitoring system off the west coast of Vancouver Island.

The pioneering system will monitor movement along the Juan de Fuca and North American plates that carry the threat of triggering an earthquake of magnitude of eight or greater.

Earthquakes of that size cause tremendous amounts of damage as seen by the 2011 Japanese and 2004 Indian Ocean earthquakes, both of which triggered tsunamis that caused mass destruction.

Researchers hope their work will help forecast these megathrust earthquakes.

"That is not possible at the moment," said Kate Moran, the Ocean Networks Canada president and CEO.

"It's the research on that path towards understanding how that plate motion impacts or changes the way these megathrust earthquakes occur," she added.

The system is made up of 21 transponders along the seafloor of the northern Cascadia subduction zone.  The transponders serve as permanent markers on the seafloor that track plate motion near the subduction fault.

The transponders' movement will be measured annually using Global Positioning System (GPS) technology. 

The challenge for researchers is that GPS doesn’t function through water, so they’ve enlisted the help of a wave glider – a marine drone of sorts that will act as a link between the submerged monitors and GPS.

"It may take a few years of missions to deliver a complete picture, given the great water depths that affect measurement accuracy and the rate of motion of the Juan de Fuca plate, which we believe is roughly four centimetres per year," said Jesse Huthinson, staff scientist with ONC.

ONC has extensive experience with this type of work, operating as many as 12,000 sensors in the ocean.

"We’re experts at installing and maintaining this technology," Moran told CTV News.

"We are probably the best in the world doing this," Moran said. "But it is a challenge because it's in the ocean; high pressure at the bottom of the ocean, cold temperatures at these locations at the bottom of the ocean, and of course the biggest challenge of all is the ocean is corrosive to any kind of metal."

All of which is factored in to the design of the monitors that are built to last for decades.

"We want to be having this observing system around for quite a long time to understand these plate motions," said Moran.