Did You Feel That? Earthquakes in the PNW
December 31st, 2015
Illustration by Christoph Niemann; Map by Ziggymaj / Getty
Contributed by Christine St. Pierre
Tuesday night, the south coast of British Columbia was awoken by a magnitude 4.8 earthquake. Just before midnight and over the period of only a few seconds, regions near Victoria and Vancouver experienced the area’s largest earthquake in years. This quake did little damage to people or property, but was felt clear down the coast of Canada into Washington State.
As I finished watching the Shakespeare play-turned-film Twelfth Night to teach my high school English classes that will resume on Monday, I happened toward Facebook near 12:20 AM. My feed was scrambling with Bellinghamsters posting statuses like “Did you feel that?” or “Well, that was my first earthquake!” Unfortunately for me, I was so absorbed in Shakespeare that I did not notice anything unusual.
This earthquake follows comically close to Kathryn Shulz’s article, published by The New Yorker, titled “The Really Big One,” which tells the all-too-familiar tale of a region of the world—this time, the Pacific Northwest—that is due for a huge—no, catastrophic—earthquake, certain to cause a tsunami that will wipe out the coast, if it isn’t already swallowed by the estimated six-foot slip of North America’s continental shelf. The article is as fantastic as it is believable, and uses history, science, and storytelling to paint a rather dim fate for the entire west coast.
Following the magnitude 9.0 earthquake that triggered a tsunami of 2011 that destroyed much of Japan and caused the malfunction of the still-leaking nuclear power plant in Fukoshima, seismologists and geologists began to take a closer look at the infamous San Andreas fault that runs along the coast of California. This wasn’t the only fault in question, though.
The lesser-known Cascadia subduction zone, which begins off the coast of Mendocino, California and runs clear to Vancouver Island (visible from Bellingham, WA), exists a few hundred miles off the west coast. Near the top of this subduction zone, we have the nerve-wracking convergence of the Juan de Fuca tectonic plate and the North American tectonic plate, which are moving in opposite directions and causing concern from individuals who spend their lives researching these natural events.
In layman’s summation, the Juan de Fuca tectonic plate is slipping slowly but steadily beneath the North American tectonic plate, upon which we all happily reside. This slip has been happening annually and in the most miniscule amount since the dawn of time, but scientists explain that this can’t happen forever—eventually, the plate will hit the craton mass at the center of the continent and spring back with elasticity, causing a massive earthquake and tsunami.
Potentially, only the southern half of the Cascadia subduction zone will give way during this rebound, releasing a quake between the magnitudes of 8.0–8.6. However, if the whole of the Cascadia subduction zone snaps back, we’re looking at upwards of 9.2. As Kenneth Murphy of FEMA’s Region X gracefully stated in Shulz’ article, “Our operating assumption is that everything west of Interstate 5 will be toast.”
Unfortunately, there was not a single warning to citizens of British Columbia last night about the earthquake. It may have been as much a surprise to scientists as it was to folks sleeping in their beds, but if estimations prove correct, we should all hope for ample warning. Friends and family, this would be a great time to sit down with loved ones and discuss tsunami evacuation routes and earthquake protocol—find the weakest and strongest spots in your house and make a plan. Pack emergency evacuation bags, maybe even have a house-drill a few months of the year, and, of course, be safe out there.
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