Three strong earthquakes rattle seabed off of Vancouver Island

Denise Titian, October 22, 2018

Earthquakes struck beneath the ocean floor west of Kyuquot on Sunday night, but there were no reports of them being felt in the community. (Eric Plummer photo)

West Coast Vancouver Island, BC — 

Three strong earthquakes raised concerns for residents of Vancouver Island overnight.

The first of three earthquakes, a magnitude 6.6 struck about 240 kilometres off the shore of Tofino on Sunday, Oct. 21 at 10:39 p.m.

It was followed at 11:16 p.m. by an M 6.8 and an M 6.5 at 11:22 pm. All of the earthquakes were relatively shallow, between 10 and 11 kilometres in depth below the ocean’s floor.

According to the National Oceanic and Atmospheric Administration’s Pacific Tsunami Warning Centre, there is no current warning, watch or advisory in effect for the region.

There have been no reports that the quakes were felt in Nuu-chah-nulth communities.

“No one in our house felt it; our community was buzzing with the earthquake post that was shared and people checked their emergency kits,” said Allison Vincent of Kyuquot.

The three strong earthquakes were followed by four aftershocks overnight, ranging from magnitudes 4.3 to 5.2 on Monday morning.

Earthquake Seismologist John Cassidy of Natural Resources Canada said that while these were big earthquakes they were not the type that generates tsunamis.

“These were not subduction quakes and they don’t really tell us when the big one might occur,” said Cassidy.

However, they are a good reminder that we live in an active earthquake zone and we should be prepared by following advice like that found on the Shake Out B.C website: https://www.shakeoutbc.ca/

Cassidy said the earthquakes were a result of horizontal slipping of the tectonic plates. They generally do not create tsunamis unless they are M7.2 or greater or, when the epicentre is closer to shore.

The ‘Big One’ will likely be a subduction zone earthquake and there is no way to know when it will happen.

“Generally, if the shaking is long and strong, that’s a good indication that a tsunami may be coming and people should move to higher ground,” said Cassidy. “Scientists will be looking very carefully at these unusual earthquakes, we will be doing very detailed studies.”

In the meantime, people should be prepared with emergency kits and plans.

“We can’t predict when the Big One will happen, but we can minimize the impacts,” said Cassidy.

Emergency kits can be purchased from major department stores or they can be made for a significantly reduced cost at home.

A basic emergency kit should contain:

  • Water – at least two litres of water per person per day; include small bottles that can be carried easily in case of an evacuation order
  • Food that won't spoil, such as canned food, energy bars and dried foods (replace food and water once a year)
  • Manual can-opener
  • Crank or battery-powered flashlight (and extra batteries). Replace batteries once a year.
  • Crank, battery-powered radio (and extra batteries) or Weatheradio
  • First aid kit
  • Extra keys to your car and house
  • Some cash in smaller bills, such as $10 bills and change for payphones
  • A copy of your emergency plan and contact information
  • If applicable, other items such as prescription medication, infant formula, equipment for people with disabilities, or food, water and medication for your pets or service animal (personalize according to your needs)

Remember to change your water and batteries every year. Your kit can be stored in a large duffel bag or a plastic tote.

Recommended additional items include:

  • Two additional litres of water per person per day for cooking and cleaning
  • Candles and matches or lighter (place candles in deep, sturdy containers and do not burn unattended)
  • Change of clothing and footwear for each household member
  • Sleeping bag or warm blanket for each household member
  • Toiletries
  • Hand sanitizer
  • Utensils
  • Garbage bags
  • Toilet paper
  • Water purifying tablets
  • Basic tools (hammer, pliers, wrench, screwdrivers, work gloves, dust mask, pocket knife)
  • A whistle (in case you need to attract attention)
  • Duct tape (to tape up windows, doors, air vents, etc.)