[Phil]

An Earthquake in Seattle

Quote

When the next very big earthquake hits, the northwest edge of the continent, from California to Canada and the continental shelf to the Cascades, will drop by as much as six feet and rebound thirty to a hundred feet to the west—losing, within minutes, all the elevation and compression it has gained over centuries. Some of that shift will take place beneath the ocean, displacing a colossal quantity of seawater. (Watch what your fingertips do when you flatten your hand.) The water will surge upward into a huge hill, then promptly collapse. One side will rush west, toward Japan. The other side will rush east, in a seven-hundred-mile liquid wall that will reach the Northwest coast, on average, fifteen minutes after the earthquake begins. By the time the shaking has ceased and the tsunami has receded, the region will be unrecognizable.

Kenneth Murphy, who directs FEMA’s Region X, the division responsible for Oregon, Washington, Idaho, and Alaska, says, “Our operating assumption is that everything west of Interstate 5 will be toast".

[Mbodell]

 Phil, on 2015-July-14, 22:16, said:

An Earthquake in Seattle

When the next very big earthquake hits, the northwest edge of the continent, from California to Canada and the continental shelf to the Cascades, will drop by as much as six feet and rebound thirty to a hundred feet to the west—losing, within minutes, all the elevation and compression it has gained over centuries. Some of that shift will take place beneath the ocean, displacing a colossal quantity of seawater. (Watch what your fingertips do when you flatten your hand.) The water will surge upward into a huge hill, then promptly collapse. One side will rush west, toward Japan. The other side will rush east, in a seven-hundred-mile liquid wall that will reach the Northwest coast, on average, fifteen minutes after the earthquake begins. By the time the shaking has ceased and the tsunami has receded, the region will be unrecognizable.

Kenneth Murphy, who directs FEMA’s Region X, the division responsible for Oregon, Washington, Idaho, and Alaska, says, “Our operating assumption is that everything west of Interstate 5 will be toast.

It was a very good article. The quote:

Quote

Counting from the earthquake of 1700, we are now three hundred and fifteen years into a two-hundred-and-forty-three-year cycle.

is also an important one to see. Makes one happier to be in central/southern California rather than the cascadia region.

[Zelandakh]

Sounds like the quote of a man getting ready for budget negotiations.

[Cyberyeti]

 Zelandakh, on 2015-July-15, 03:12, said:

Sounds like the quote of a man getting ready for budget negotiations.

I watched a documentary on this some years ago now, I don't think anybody disputes it's real, it's going to be really bad just nobody knows when and exactly how bad.

Compare with the potential east coast megatsunami due to the mountainside falling into the sea in the Canaries, where some research is now suggesting that it may slide as several smaller chunks which may mean no disaster for the US.

[billw55]

One thing that interested me in the article was the relative lack of smaller quakes in the region, which was not really explained.

[kenberg]

We were recently on the Pacific Coast in Oregon and Becky, who lived in S.F in her adolescence, really felt at home. Being 76, the one in five chance that I might die from a quake in the next fifty years is not all that intimidating. But probably we stay put in Maryland.

Of course even an egocentrist recognizes that there are other , and younger, people in the world. There are warning signs along the coast advising a person to immediately seek high ground if there is a rumbling of the earth, but from the article it sounds more useful, with a three minute rumble, to say your last goodbyes.

If I were 20 and living on the coast what would I do? I dunno. But I am not.

[Zelandakh]

 kenberg, on 2015-July-15, 06:58, said:

If I were 20 and living on the coast what would I do? I dunno. But I am not.

Grab the nearest willing 20 year old girl and go out in style?

[akwoo]

 kenberg, on 2015-July-15, 06:58, said:

If I were 20 and living on the coast what would I do? I dunno. But I am not.

It depends on where. Along most of the Oregon/Washington coast, a slightly less fit than average 20 year old who knows their local area would have no trouble being 100 feet higher in 15 minutes. This is true even in most of Seattle, though that might be a place where 100 feet isn't enough. (To give you some idea, Sea-Tac airport - admittedly on top of a hill - has a higher elevation than the Albany, NY airport.)

[kenberg]

 akwoo, on 2015-July-15, 13:13, said:

It depends on where. Along most of the Oregon/Washington coast, a slightly less fit than average 20 year old who knows their local area would have no trouble being 100 feet higher in 15 minutes. This is true even in most of Seattle, though that might be a place where 100 feet isn't enough. (To give you some idea, Sea-Tac airport - admittedly on top of a hill - has a higher elevation than the Albany, NY airport.)

I was just taking the guy in the article at his word that everything west of I-5 would be toast. I was speculating on whether I would move if I lived in, say, Lincoln City OR. Probably not. But if I had a young family? Maybe.

We hiked out on Cape Lookout. It says we went up 450 feet, so I guess that would do it, but sitting out a tsunami there would be interesting at the least. On another trip, this one by myself, I was on Orca.and other islands in Puget Sound. I had my bicycle with me and I recall going up some fairly long hills (i was younger) but still a tsunami would be a challenge I think.

Anyway, I very much like the Pacific Coast, and Becky is even more enthusiastic than I am. We stay here for kids and grandkids, and it is pretty nice here as well, but that might well be subject to change.

So my point was: It's lovely out there, but if I were 20 and planning my life, how would I evaluate this against the serious threat of a truly major quake? As I say, I am not sure. Very few choices are clear cut.

[barmar]

 kenberg, on 2015-July-15, 17:03, said:

So my point was: It's lovely out there, but if I were 20 and planning my life, how would I evaluate this against the serious threat of a truly major quake? As I say, I am not sure. Very few choices are clear cut.

It seems like wherever you choose to live, there's some kind of major natural disaster that could destroy your home. Hurricanes in the Atlantic and Gulf coasts, blizzards in the north, tornados in the prairie states, earthquakes along the San Andreas. And climate change seems to be making "100 year storms" happen every few years -- we haven't yet figured out what the new normal is.

[billw55]

 barmar, on 2015-July-16, 09:05, said:

It seems like wherever you choose to live, there's some kind of major natural disaster that could destroy your home. Hurricanes in the Atlantic and Gulf coasts, blizzards in the north, tornados in the prairie states, earthquakes along the San Andreas. And climate change seems to be making "100 year storms" happen every few years -- we haven't yet figured out what the new normal is.

I wonder how it was decided what a 100-year event is to begin with. We clearly don't have enough centuries of data to assign this empirically.

[y66]

We all have our little faults. Mine's in California. -- Lex Luthor in Superman

[barmar]

 billw55, on 2015-July-16, 10:00, said:

I wonder how it was decided what a 100-year event is to begin with. We clearly don't have enough centuries of data to assign this empirically.

Most natural events follow a general pattern called a power law. This can be used to estimate the frequency of rare events from the frequency of similar, but more common, variants. So if you have empirical data about the frequency of earthquakes from Richter levels 1 through 5, you can extrapolate to estimate the expected frequency of 6 and 7. The same thing can be done with hurricane and blizzard intensities.

But this assumes that the general conditions that cause the events haven't changed. If there's been a significant change in climate, you can't depend on past weather history to estimate future events as accurately.

[Mbodell]

 barmar, on 2015-July-16, 14:34, said:

Most natural events follow a general pattern called a power law. This can be used to estimate the frequency of rare events from the frequency of similar, but more common, variants. So if you have empirical data about the frequency of earthquakes from Richter levels 1 through 5, you can extrapolate to estimate the expected frequency of 6 and 7. The same thing can be done with hurricane and blizzard intensities.

But this assumes that the general conditions that cause the events haven't changed. If there's been a significant change in climate, you can't depend on past weather history to estimate future events as accurately.

There are also models that are based on characteristics of the faults that talk about the maximum size of an earthquake (or other phenomenon). Which is why the biggest Earthquake near Seattle (over, say, a couple thousand years) will be bigger than the biggest Earthquake near San Francisco (over the same time period). Or at least that's what the models say.

[barmar]

That's a somewhat different point. The power law addresses the frequency of events of different levels, not the worst case scenario.

Also, earthquakes in San Francisco and Seattle are different events, they each have their own history and their own power law distributions of severity.

[y66]

That's a heckuva story. Incredibly well written. Here's the scoop on the author:

Quote

Kathryn Schulz joined The New Yorker as a staff writer in 2015. Previously, she was the book critic for New York, the editor of the environmental magazine Grist, and a reporter and editor at the Santiago Times. She was a 2004 recipient of the Pew Fellowship in International Journalism and has reported from Central and South America, Japan, and the Middle East. She is the author of “Being Wrong: Adventures in the Margin of Error” (2010).

Quote

Where we stumble is in conjuring up grim futures in a way that helps to avert them.

I asked Dougherty about the state’s long-range plan. “There is no long-range plan,” he said.

[Al_U_Card]

Happily, 100 year events are infrequent and isolated relative to our longevity and mobility. Also, a warmer globe is a less violent one (climate-wise) at least over recorded history.
Eq-proofing your abode is like insulating/reinforcing against the cold and snow, a prudent expense. Better living where you can make a living and adapt to the locale, as mankind always has relative to the uncontrollable forces of nature.

[blackshoe]

One of my acquaintances is the creative director of a gaming company based in the Seattle area. Asked whether this potential disaster might induce him to move, he said "My job is here. My friends are here. I am not going to organize my life around some 'potential disaster'".

OTOH, I recall a cold war short story by, I think, Spider Robinson or Larry Niven, in which two scientists from Brookhaven National Labs are sitting in a local bar discussing the looming possibility of a nuclear attack, and the fact that such an attack would target major cities like New York. Finally one of them says "Let's ask Joe (the bartender) what he he thinks. He's a pretty wise man." They look up, and Joe's rag is sitting on the bar, and Joe, who had been listening to this conversation all along, is gone.

[mike777]

 Phil, on 2015-July-14, 22:16, said:

An Earthquake in Seattle

VERY MISS LEADING TITLE OF THREAD.

Water is the great killer here, water is the great destroyer here

Water kills, water destroyer
---


Very interesting article in the New Yorker

[blackshoe]

I guess we should all switch to beer, then.