Tuesday, October 14, 2014

Faculty voice: Get prepared in case ‘the big one’ strikes

By Susan Smythe
Chair of Geography
Geography Chair Susan Smythe.

Douglas College

“The big one” might or might not strike the West Coast in our lifetime, so it’s important to be prepared.

The B.C. coast periodically produces major earthquakes and tsunamis created by interacting tectonic plates, chunks of Earth’s crust that move past each other horizontally or vertically. These plates move at about the speed your fingernails grow.

They may “stick” for hundreds of years, storing up energy that is released when the rock finally ruptures and slips to a new position. This creates an earthquake with seismic waves radiating out like ripples from a stone dropped in a puddle.

The greater the rock movement and the longer the fault over which it occurs, the greater the magnitude of the earthquake. The amount of ground shaking depends on our distance from the site of rupture, and the underlying material. Essentially, loose sediment equals more shaking; hard rock equals less shaking.

We live on the North American plate. It’s colliding with little plates to the west like the Juan de Fuca. The thinner, more dense Juan de Fuca plate descends, or subducts, into Earth’s interior beneath the thicker, less dense North American plate.

The North American plate is locked, or is “sticking,” to the Juan de Fuca plate. As collision continues it is slowly buckling. Geoscientists are measuring its leading edge as it shortens and elevates, just like in Indonesia and Japan before their devastating earthquakes.

One day the North American plate will “snap out” and produce a great earthquake. It may form tsunami waves as it “kicks out” at the bottom of the ocean.

Studies have shown magnitude 9 earthquakes with tsunamis in our coast’s past, most recently on January 26, 1700. We can calculate an average recurrence interval, but can’t predict when the next one will hit because those events weren’t evenly spaced in time.

Geoscientists guarantee that we will have a “megathrust” earthquake one day, but we have no way of knowing whether it will be next week or in 700 years.

The Great British Columbia ShakeOut drill, taking place Oct 16, is a great reminder to prepare our families and homes for a large earthquake. Douglas College has made plans to protect us in an emergency. Now it’s your turn to prepare, and happily, there are many wonderful resources to help you.

The getprepared.gc.ca website will guide you through an emergency plan for your family, as well as emergency kits for your home and vehicle. Use the PEPBC emergency contact form to type in the name of your out-of-province contact and print off six business cards with contact information for your family members to carry in their wallets. The New Zealand government has created a brilliant video of what to do in an earthquake.

Sometime in the next week, take one step to begin or add to your emergency plans with your family. If we take no precautions and a significant earthquake strikes in our lifetimes, we will regret our inactivity. If we plan ahead, we may reduce hardship and possibly save lives of people we love.