Thinking About Quakes And Tsunamis

The outside expert gets the most attention. Within the last few days, an article was published in the New Yorker that described the possible impacts of a major earthquake in the Pacific Northwest. Suddenly, the earthquake possibility is a topic of conversation. There are plenty of local experts, but the only reports I think that have generated more commentary were the reports right after the earthquake and tsunami in Indonesia, and again in Fukushima. Good. I’d rather hear we’re talking about it because someone was talking about it, rather than because a similar disaster had hit some other group of people. The big question is, what do you do about it? The answers are highly individual. I have mine, I think.

As I’ve written before;

I live over an earthquake fault, have to drive through a tsunami zone to get home, am within about a hundred miles of three large volcanoes, and live on an island that is only tied to the mainland by one bridge and two ferries. Do I worry much? No, at least not about that. – What Me Worry

Sounds like a long list of potential threats, and it doesn’t even mention The Big One described in the article. Each of the local threats is big enough to make the news, but a major earthquake along the Cascadia Subduction Zone and the Juan de Fuca Plate hits much more than my piece of my island, and can be more damaging that an eruption on Mt. Rainier or Mt. Baker, even with the mud flows included. The local faults kicking off a 6.0-7.0 are only 1% as powerful as a Cascadia quake that could be 8.0-9.0. As we saw in Indonesia and Fukushima, the quake is devastating, and so is the tsunami. I wouldn’t be surprised if such a large quake kicked off other quakes, upset at least one of the volcanoes, and triggered a series of landslides. One estimate showed Seattle getting abut 30,000 landslides. The area would be a mess, and the area would be enormous.

As one of the local officials was quoted in the New Yorker article,

“Our operating assumption is that everything west of Interstate 5 will be toast.” – Kenneth Murphy, FEMA

Scared? Not a surprise.

With threats like that it is understandable if people decide to move somewhere safer. It is easy to point fingers at people who live in flood zones, try to farm in deserts, or expect to get around during blizzards; but every area has its dangers and potential disasters. This one is just a bit spookier because it is so extensive and will probably happen without warning. It could happen as I type. Nope. Not yet.

Let’s walk it back a bit. Cascadia + quake does not equal 9.0 and tsunami. There could be a series of quakes that release the energy in smaller packets. They’d still be bad, but they may not be disasters. We know the fault kicks off such quakes, but they’ve also learned that there are some slow, soft, long-period quakes and slides that move the earth in ways they don’t understand, yet. The Cascadia tsunami will hit the western shore within about 15 minutes after the quake, but not every quake produces a tsunami. That fault line is tens of miles out to sea, and Seattle is tens of miles in from the coast. Every mile is a bit more protection. Puget Sound and the Salish Sea could see a tsunami, but it may not make it around the corner and down to the major population centers of Olympia, Tacoma, Seattle, and Everett. Bellingham and Vancouver will have an issue. I haven’t checked Portland.

You can learn a lot by listening to the local experts that have been studying this for years. The University of Washington, USGS, NOAA/PMEL, and others have released their studies, given lectures, and talked to local officials. Many residents may not have heard the tales; but, their findings are one of the reasons Seattle is taking down the harborfront highway called the Alaskan Way Viaduct (and then for some bizarre reason replacing it with a tunnel – but that’s a fiasco to post about later.)

  • The Washington State Department of Transportation produced a video that shows what would happen to Seattle’s waterfront. WSDOT Alaskan Way Viaduct
  • NOAA PMEL produced one that shows the regional coastline effects. Simulated Cascadia Tsunami
  • NOAA PMEL also produced one that shows what happens to Whidbey Island, at least the north half. RawTsunami grabbed it and reposted it. Anacortes Whidbey Inundation

In every case, bad things happen; but not everywhere. The advantage we have is the ability to look ahead and prepare now.

One of my more entertaining writing jobs is with Curbed Seattle. Mostly, the assignments are light-hearted articles about real estate; but, occasionally my accommodating editor lets me write about other things. So, I wrote a series about quakes and tsunamis and Seattle.

One of the ironies is that some of the most stable ground is in the most affordable neighborhoods. The tsunamis, however, are purely a function of elevation. Waterfront properties have problems, but so do low-lying neighborhoods that have no view, no grand infrastructure, and no great say in governance.

Seattle’s issues and Whidbey’s issues are linked in ways that ignore the Cascadia fault. Seattle sits on a fault. South Whidbey sits on a fault. Quakes on either are felt by both. Each throws tsunamis at the other. I live beside Cultus Bay, (and did a twelve month photo essay of it)November Sunset which is pointed like a funnel for any tsunami coming up the Sound. It’s even a region for a field study in paleo-tsunami. A similar field report convinced me to buy high, as in 100 feet above sea level. The tsunamis haven’t been that big, and at this elevation the details don’t matter as much.

There is a lot of debate about climate change and sea level rise. That’s another reason I don’t want to own no-bank waterfront (beside not being able to afford it.) Quakes change the debate, or give the local debate a different perspective. Some estimates suggest that global sea levels will rise a few feet in a century or so. A subduction quake, like Cascadia, does more than shake the land. The land on one side of the fault bounces up. The land on the other side of the fault drops down. Similar quakes have dropped land six feet in less than ninety seconds. Waterfront becomes underwater, regardless of the equity and the mortgage. Harbors become deeper. Coastal forests drown. The shift is also lateral. In Chile, one quake moved the land fifty feet to the side. The shift causes damage, of course, and then it kicks off great debates about who owns what. People who are meticulous about surveying their property boundaries might just collapse with the prospect of not knowing whether they can tell the kids, or anyone, to get off their property.

As I said, luckily, we can look around and look ahead, and act now. FEMA and the Red Cross have suggestions about preparedness. Simply enough, I have earthquake kits in the truck, and outside the house.DSC_5740 Living on the south end of a 58 mile long island that has its power come in from the north, I’m practiced at dealing with minor power outages. The Big One, even if it is local, may mean a major outage of weeks. I may not be totally prepared for that, but if I keep a full pantry, keep the rain barrel full, and make sure I have shelter, I can probably get by. Good thing I have backpacking gear.

The response to the New Yorker article surprised me. I’ve studied the situation, considered the possibilities, arranged for some contingencies, and then move on to other things. The knowledge, the history, my earthquake kits, and the choices I’ve made mean I know I’ve reduced my risk as much as I think is reasonable. One of the benefits of a frugal lifestyle is realizing how little is necessary. (Frugal Disaster Preparedness) If I had more money, I’d buy a solar station, and a solar oven. Maybe later.

The greater surprise is how vulnerable many people are. I hear that in their reactions to the article. A 9.0 would be a major disaster. I expect to be affected. But, I don’t worry about it. Frequently though, and especially after such an article or event, I look across the bay at a group of houses that have awesome views. They sit on or below the bluffs of the other southern point of the island. They have views due south down the Sound. Some can probably see Seattle. I’m sure they can see Mt. Rainier. I take photos of it occasionally because I get the feeling I’m looking at a “Before” picture, and hope the “After” picture looks the same, but suspect not.

DSC_5742PS – For those who want to really get confused, check out what’s happening with the Axial Seamount. It is an underwater volcano near one corner of the Cascadia fault line. It’s erupting.

About Tom Trimbath

real estate broker / consultant / entrepreneur / writer / photographer / speaker / aerospace engineer / semi-semi-retired More info at: and at my amazon author page:
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1 Response to Thinking About Quakes And Tsunamis

  1. Sue says:

    I definitely see an “up” side to this report – maybe all those folks thinking of flocking to Seattle to outrun global warming will now think twice….. yippeee! And while the thought is scary, let’s face it, a Dreamlifter could crash-land on our house tomorrow, or on anyone’s house anywhere, or we could drop dead from eating all the toxic chemicals in food, or some sad lunatic who has snapped from the pressure of living in this chaotic world opens fire with a legal weapon of mass destruction……. the point is…. be prepared and don’t worry about it. Live in the moment. Be joyful. This comes from one who went through a major quake in Santa Cruz in 1989….. it happens. We all gonna die sometime! 🙂

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