The Really Big One (Portland, Seaside: 2015, loans, house)

[PDXJ]

Good article just published about the next "slip" of the Cascadia Subduction Zone and what it would likely mean for the Northwest and Portland:

The Really Big One - The New Yorker

Historically, these huge quakes have occurred on average every 243 years, we're now 315 years since the last one.

[CanuckInPortland]

That article is basically assuming the absolute worst case scenario in terms of magnitude which is frightening. It's assuming a 9.0 quake where the entire zone goes rather than just an 8.0. Though saying "everything west of I-5 is toast" is both slightly misleading for different reasons. If the entire subduction zone goes and not just the first half of the zone, the resulting tsunami is going to destroy most of the coast, though not reach Portland(Seattle could be affected by inland surges)---the shaking however is going to affect most of the terrain west of the Cascades(I-5 means nothing, it'll be everything up to the foothills). Though if just one part of the zone goes---places further away might not be as damaged by the actual shaking(the 9.0 quake in Japan a few years back didn't damage Tokyo very much). The one thing the Northwest has going for it in regards to a tsunami is simply that most of the population isn't directly on the coast.

Seattle is going to worse off than Portland because it's hillier, downtown Portland and the West Hills will be devastated, though the mostly wood-built homes on the Eastside and suburbs might fare better. The destruction of infrastructure though will be the biggest risk, because you'll have a lot of places cut off from each other(and power and water). The bridges are way out of date in regards to surviving a huge quake.

In the end everything will get rebuilt as it always does after a huge disaster--look at how many times cities in other parts of the world(or in the US) get rebuilt after catastrophic events. The cities along the Gulf/Atlantic basically know they're at constant risk of huge hurricanes, California is going to get hit by an huge earthquake too again, and parts of the Midwest and Plains and inland South are always getting massive tornadoes. It's all a crapshoot.

Also though this earthquake prediction is nothing new--I've read about it for years now, and it's well known in the region. It's scary, but only someone with little knowledge of the region would look at those volcanos surrounding us and not know that we live on the "Ring of Fire".

[luv4horses]

Oh goodie. Now property values will go down! But to buy you'll need to pay cash, no 30 yr loans. (jk)

Actually, that is a very intriguing article. But truly it does not seem that one could ever really prepare for something like that. The best that could happen would be to have a way to shut down the gas lines and other power sources, and to have a doomsday plan in place to handle ramifications. But there would be no way to save the lives, buildings, electronics, etc. and it might be a waste of effort to attempt to do so.

[emathias]

That's one way to crowd-control the hipsters ...

[PDXJ]

Originally Posted by CanuckInPortland

Also though this earthquake prediction is nothing new--I've read about it for years now, and it's well known in the region.

True, it's not exactly news but a good reminder for people who are here for the long-term and get complacent (like myself), and perhaps news to many others, including people recently moved or looking to move here.

Originally Posted by CanuckInPortland

That article is basically assuming the absolute worst case scenario in terms of magnitude which is frightening. It's assuming a 9.0 quake where the entire zone goes rather than just an 8.0.

Yes, but as I read it in the article, the odds of a 9.0 (or greater) hitting in our lifetimes is not insignificant, and it will happen eventually, so is probably worth preparing for. And something in the lower range (8.0-8.6) would still likely be a major disaster.


(from article):

The last major Cascadia subduction quake was 1700, and it was estimated to be a 9.0 It's been 315 years since then.

A similar event (8.0-9.2) is estimated to occur on average, every 243 years.

Odds of occurence in the next 50 years are:

1 in 3 for a 8.0-8.6
1 in 10 for a 8.7-9.2

[CanuckInPortland]

Originally Posted by PDXJ

True, it's not exactly news but a good reminder for people who are here for the long-term and get complacent (like myself), and perhaps news to many others, including people recently moved or looking to move here.



Yes, but as I read it in the article, the odds of a 9.0 (or greater) hitting in our lifetimes is not insignificant, and it will happen eventually, so is worth preparing for. And something in the lower range (8.0-8.6) would still likely be a major disaster.


(from article):

The last major Cascadia subduction quake was 1700, and it was estimated to be a 9.0 It's been 315 years since then.

A similar event (8.0-9.2) is estimated to occur on average, every 243 years.

Odds of occurence in the next 50 years are:

1 in 3 for a 8.0-8.6
1 in 10 for a 8.7-9.2

Though those odds are from one study. The truth is that we don't even really know about how many massive earthquakes have struck at that magnitude over history. It's very difficult because there hasn't really been one large quake within modern recorded history in the Pacific Northwest There's even some scientists who believe an 8.0 magnitude quake struck part of the zone in the 1800s(though the area was basically still sparsely settled at the time). We really know a lot about the timing of the 1700 quake because of the tsunami that hit Japan at the same time.

Also, it's hard to say a fault line is overdue for a quake--a quake could hit tomorrow or it could hit in 800 years. They're taking an incredibly large standard deviation when they're talking about average years between massive quakes. Some scientist estimate there's been massive quakes maybe 19 or 20 over the last 10,000 years, but there's no way of saying a place is overdue for a quake--science doesn't really work like that. They don't even know truly how long it was between the 1700 quake and the largest one previous to that.

People should be prepared for the possibility, but it's hard to say that a quake will definitely hit in our lifetimes--like I said, it could happen tomorrow or it could generations away. At minimum people should just have some level of emergency supplies in their homes for any sort of possibility. If you want to be somewhat safer for the possibility--live in a wood-framed home rather than an older one made of bricks or stone.

[oldtintype]

I was in the SF earthquake in '89. It was bad but it wasn't that bad. I'll take my chances. The only "worst case scenario" I ever saw come true was New Orleans, which granted, was indeed bad!

[mrcnkwcz]

Originally Posted by emathias

That's one way to crowd-control the hipsters ...

How does one go about crowd-controlling the incorrigibly flippant Chicagoans of the world? Sending them into the heart of the south side of Chicago, then disabling their GPS?

[LacyPetunia]

Canuck, I understand your reservations. Nonetheless, perhaps the people in the NW need a little worst case scenario to make them pay attention and at least make some preparations. Plus, to downplay the study seems a bit blasé.

While you're correct when you say it's hard to predict when a quake will occur, I think in the case of the Cascadia quake, it's "reaching" to say it could be as much as "800 years" before it hit.

I've been though 3 earthquakes in my lifetime, the last one being the Loma Prieta. I can promise you that you aren't thinking about anything else but the shaking and rolling ground when it's happening. "Statistics" never enter your mind.

BTW, do you live in the Northwest?

[CanuckInPortland]

Originally Posted by LacyPetunia

Canuck, I understand your reservations. Nonetheless, perhaps the people in the NW need a little worst case scenario to make them pay attention and at least make some preparations. Plus, to downplay the study seems a bit blasé.

While you're correct when you say it's hard to predict when a quake will occur, I think in the case of the Cascadia quake, it's "reaching" to say it could be as much as "800 years" before it hit.

I've been though 3 earthquakes in my lifetime, the last one being the Loma Prieta. I can promise you that you aren't thinking about anything else but the shaking and rolling ground when it's happening. "Statistics" never enter your mind.

BTW, do you live in the Northwest?

I live in Portland, I was born in Vancouver BC, though I've lived in 4 other places in my life in the US and Canada.

Nowhere did I say that people shouldn't be prepared, in fact I specifically said people should be prepared, look at what type of house they're living in--maybe look at getting a retrofit of an older home if it's not bolted to the foundation, and definitely have emergency supplies on hand for any type of possible catastrophe.

However, since this New Yorker article has gone viral in the social media sphere--I've had nonstop people tell me that there's a definite 1 in 3 chance that we have an massive earthquake in our lifetime--and that it will no doubt kill at least 13,000 people. Everything west of I-5 will definitely be toast. People quoting the article that since there's one study estimating a large earthquake every 243 years means that we're due any day(while other studies show an average of 500 years and gaps up to 700-1000 years between earthquakes) There's been concern about an earthquake in the Northwest since the Nisqually quake--and before that since scientists have been studying the subduction zone more intently since the 1980s. There's a reason that you see tsunami evacuation zones and routes along the entire Oregon coast. Yet, somehow people read one article and it's like the first time they realize that we live on the edge of the Ring of Fire.

Look at this way, California, Alaska, Japan, Chile, Mexico, and so on are all just as at risk for the threat of large earthquakes as us--and they're more frequent there. But people go on living with the risk. I've had relatives that have lived through the Loma Prieta quake too and earthquakes in Taiwan also. If the theorized massive tsunami after a 9.0 earthquake does happen--most of the Oregon Coast to Vancouver Island is toast for sure. If it's truly a 1 in 3 possibility, we should probably start moving people away the from lower parts of the coast en masse, disallowing any new building ever in places like Seaside. Though that's not going to happen--people will just be at risk for an earthquake that could strike tomorrow or not in our lifetimes.

I agree that perhaps the fear this article inspires is a good thing if it gets people off their butts to prepare more for a quake(or governments to do more about it)--though at the same time if the big 9.0 quake does happen as described in the article tomorrow there's not much many or going to be able to do about anything. Though on the other hand, most of what we know about the potential effects of a Cascadia zone earthquake are based on speculation--though there's been massive 9.0 or 9.5 earthquakes in other parts of the world and the damage and those places still exist after rebuilding.