When my wife and I decided to move from Austin to Bainbridge Island, Washington in 2018, a friend sent me a New York Times article called The Really Big One. It’s a gripping and thorough look into what will happen when the Cascadia Subduction Zone produces a megathrust earthquake and tsunami in the Pacific Northwest.
If you want the Cliffsnotes version, it isn’t good. The author quotes the FEMA director for the region as saying, “Our operating assumption is that everything west of Interstate 5 will be toast.”
Back in 2018, this information was news to me. Having lived in Texas for most of my life, I hadn’t considered that highly-populated portions of the United States could be at risk of such massive natural disasters.
What is the Cascadia Subduction Zone?
The Cascadia Subduction Zone, or CSZ, is a fault line that stretches the length of Northern California, Oregon, Washington, and Vancouver Island. When the two plates of the CSZ eventually slip past each other, they will produce the most powerful kind of earthquake that occurs on Earth. Subduction zones are capable of producing magnitude 9.0 and larger earthquakes. If you need a refresher on the Richter scale, here’s a good video. Anything 9.0 and greater is considered “extreme”, producing catastrophic destruction.
The CSZ is the same type of fault line that produced the devastating magnitude 9.0 Indian Ocean earthquake in 2004. That earthquake triggered a tsunami that reached as high as 100 feet while traveling inland. It was the most powerful earthquake ever recorded in Asia, and resulted in an estimated 228,000 lives lost.
The 2011 magnitude 9.1 earthquake and subsequent tsunami that killed 18,000 people in Japan was also a subduction zone event.
What Are the Odds?
It’s important to remember that a Cascadia Subduction Zone earthquake and tsunami is a question of when, not if.
Seismologists have forecasted a 37% chance that the CSZ will produce a 7.1+ magnitude earthquake in the next 50 years, and a 15% chance that it will produce a magnitude 9.0 or higher earthquake.
According to geological evidence, the Cascadia Subduction Zone has historically triggered a megathrust earthquake approximately every 250 years. The last one was in 1700, long before any European settlers had made it to the West Coast. That event is estimated to have produced an earthquake with a magnitude of 9.0, as well as a major tsunami that reached as far as Japan. By doing some simple math, you could say we’re overdue for the next one.
How to Get Ready
You may be wondering if I went ahead with my move to the Pacific Northwest after learning about the earthquake risk. The answer is, yes. My family lived on Bainbridge for three years, and we thoroughly enjoyed our time there. I have yet to find a more beautiful part of the country.
Our time in the PNW was also the impetus for my personal journey into crisis readiness. I was determined that if we were going to live somewhere that had such a serious risk of a major natural disaster, we needed to be as ready as possible.
So if you live in an area that will be affected by a Cascadia Subduction Zone earthquake, what should you do?
In 2022, Washington State emergency officials and National Guard, in coordination with FEMA and various state and local agencies, conducted a simulated CSZ earthquake and tsunami exercise called “Cascadia Rising.” The exercise was intended to assess how bad a CSZ disaster would be. Here’s a video recap of some of their findings:
Cascadia Rising Estimates
- 8,440 killed
- 12,114 injured
- 507,000 buildings destroyed or damaged
- 1,274,000 people without food or water
- Complete or severe damage to transportation infrastructure west of I-5
- 30% of fire stations destroyed
- 48% of police stations destroyed
- 36% of hospitals unusable
It’s easy to focus on the deaths and injuries that will be caused by a CSZ earthquake and tsunami, and to overlook the long-term humanitarian crisis that will follow. For the majority of the people who will survive the CSZ earthquake, their world will be completely destroyed for a significant period of time. Rebuilding will not be fast.
Imagine living for months without electricity, drinking water, food supply chains, hospitals, and first responders. The destruction will be on a scale never before seen in the United States. Officials who were part of the “Cascadia Rising” exercise plainly stated that citizens should not expect the government to come to their assistance immediately following this event. There will be relief efforts, to be sure, but they stressed the importance of being as self-reliant as possible. It will be a matter of survival.
A good starting point for getting ready is 7 Steps to Disaster Readiness. However, if you live in an area that will be affected by the CSZ earthquake, you really need to go beyond this basic level of readiness. I would recommend stocking up on as much food and water as you can manage. Make sure that you have a very comprehensive medical kit stashed away – you won’t be able to find those items after the disaster. You also need to have a plan for personal security.
If you’re interested in beginning your journey into disaster readiness, I would highly recommend that you start by taking Guide to Disaster Readiness. In this course, you’ll learn the most important first steps for getting your household ready for a disaster. From there, I would suggest taking Secure Your Grid-Down Home to learn the ins and outs of how to make your home livable and safe after a major disaster.
Parting Thoughts
I sincerely hope that a Cascadia Subduction Zone earthquake doesn’t happen for many, many years. If you live in an area that faces a threat from this disaster, please take the time and make the investment to get your household ready. It’s an insurance that you can’t afford not to have.
