The Cascadia Subduction Zone: Don't Be Scared, Be Prepared

Ronni Deam
Aug 10
2 min read

The Big One’s VIP Waiting Room

If you live in the Pacific Northwest, you’ve probably heard of the Cascadia Subduction Zone—our region’s 600-mile-long “troublemaker” hiding just offshore. It’s where the Juan de Fuca plate is sliding under the North American plate, quietly building tension.

How ready are you for the Big One?

I'm fully stocked and ready!
I have some supplies ... somewhere
I have a flashlight in a junk drawer and that's about it
I hate thinking about it so don't ask

Scientists say Cascadia is capable of producing megaquakes (magnitude 8–9+) about every 300–600 years. The last one was in 1700. Do the math, and… well… let’s just say we’re not exactly early in the cycle.

The Science (Without Putting You to Sleep)

Here’s the short version:

Subduction = One tectonic plate dives under another.
Over centuries, stress builds along the fault.
Eventually, that stress snaps loose, causing massive shaking and, potentially, a tsunami.
If you live on the coast, that wall of water could arrive in 15–30 minutes.

Think of it like pulling a rubber band farther and farther back… eventually, it will snap. Cascadia’s just taking its sweet time.

Why You Should Care (Even if You’re Inland)

A Cascadia event wouldn’t just be a “coastal problem.” We’re talking shaking across Washington, Oregon, Northern California, and British Columbia. Bridges could be out, power could be down, and your phone may not function.

How to Prepare Without Becoming That Doomsday Neighbor

Preparation doesn’t have to mean living in a bunker or sewing your own clothes from tarp scraps. Here’s a practical, non-apocalyptic plan:

Water, Water Everywhere (But You Can’t Drink It) Store at least one gallon per person per day for a minimum of two weeks. Bonus points if you keep it somewhere you can reach without moving your heavy “seasonal decorations” box.
Food That Won’t Judge You Canned goods, protein bars, peanut butter—anything that lasts without refrigeration. And yes, chocolate counts as morale food.
Make Friends with Flashlights Headlamps are even better—they keep your hands free for important things, like opening that jar of peanut butter.
Shoes by the Bed Quakes don’t RSVP. Keep sturdy shoes next to your bed to avoid stepping on broken glass at 2 a.m.
Tsunami Smarts If you’re in a tsunami zone and you feel strong shaking, don’t wait for an official alert. Move uphill, fast—think “late for work” speed, not “Sunday stroll” speed.
Know Your Neighbors You don’t have to host block parties, but exchanging contact info and knowing who might need help could be lifesaving.

The Silver Lining (Sort Of)

The good news? You’re already better off than people who pretend earthquakes don’t happen. And unlike other disasters, earthquakes don’t give you months of ominous news headlines. The bad news? …They don’t give you months of ominous news headlines.

So here’s the deal: prepare a little at a time, keep your sense of humor, and remember—resilience isn’t just about gear, it’s about mindset.

When (not if) the Big One comes, you’ll be the person with light, food, water, and the ability to calmly open your chocolate stash.