51–60 of 118 posts
Note that Washington deployed the ShakeAlert earthquake early warning system just yesterday--here's how to enable it on your phone: https://mil.wa.gov/alerts
https://pnsn.org/tremor?starttime=2021-04-01T00:00:00&endtim...
"Our operating assumption is that everything west of Interstate 5 will be toast." Ouch.
It's a weird statement to make, because the route of I5 is fairly arbitrary, geologically speaking. Lower parts of downtown Seattle may be at risk, but is upper Queen Anne hill? Ballard may be partially screwed, but Crown Hill is hundreds of feet higher in elevation. That assumes that Puget Sound even generates a large Tsunami based on an offshore quake. If we're talking about Oregon it gets even weirder since the po…
You sure about that? From Olympia to the Oregon border I-5 sits on the lowest, flattest stretch of land between the coastal range and the cascades. That's why it keeps getting flooded out by the Chehailis river.
To the north, through Whatcom County the route is anything but geologically arbitrary: it's the unique route that required the minimum amount of blasting into Chuckanut rock.
Parent post seems like a pretty city-centric view of the world. The dozen or so miles that pass through Seattle might be arbitrary to within a Seattle-diameter, but that's an irrelevantly small part of the freeway.
"Our operating assumption is that everything west of Interstate 5 will be toast." Ouch.
It's a weird statement to make, because the route of I5 is fairly arbitrary, geologically speaking. Lower parts of downtown Seattle may be at risk, but is upper Queen Anne hill? Ballard may be partially screwed, but Crown Hill is hundreds of feet higher in elevation. That assumes that Puget Sound even generates a large Tsunami based on an offshore quake. If we're talking about Oregon it gets even weirder since the po…
The real risk is civil engineering in nature. While the fault is some distance away, it will shake hard and for a long time. Unreinforced masonry will probably be destroyed, and Seattle has a lot of old masonry in some neighborhoods. Some older structures not up to the current seismic code will likely fare poorly. Seattle has had enough local 7+ earthquakes that a distant offshore 8-9 won’t feel too much different, but the shaking time will be much longer. Landslides are undoubtedly a risk.
Portland will likely fare much worse than Seattle. A modern steel or wood-framed building constructed in the last 20 years will very likely survive almost anything, they are built for it. Older steel and wood buildings that are still standing have already been through some earthquakes; not as large but they won’t immediately collapse.
The real problem will be restoring infrastructure in the aftermath.
Would not be complete without this fantastic article: https://www.newyorker.com/magazine/2015/07/20/the-really-big...
I think that article is best paired with this followup: https://www.newyorker.com/tech/annals-of-technology/how-to-s... in particular this hedge: > Perhaps no line in the entire six-thousand-word piece attracted as much attention as this declaration by Kenneth Murphy, head of the fema division responsible for Cascadia: “Our operating assumption is that everything west of Interstate 5 will be toast.” The first importa…
If including "a million buildings destroyed" (or whichever other part you felt you couldn't include) would make your comment seem less devastating, it just isn't that devastating. It's fine. Representing things accurately is more important than... whatever we were hoping to achieve there. Seeming cool for knowing the original article was BS, I guess?
It's a good article! I don't think it's BS. I might think that if I read your partial excerpt, but that's a problem with the excerpt.
"Our operating assumption is that everything west of Interstate 5 will be toast." Ouch.
This shouldn't be in the article. It's unscientific, non-technically, and pretty much meaningless.
It's very difficult to describe how bad this earthquake is expected to be for a large swath of the Pacific Northwest when it happens again (and it's when, not if). It will be similar to Fukushima except absolutely nothing in the region is designed for earthquakes of this magnitude, not to mention the expected tsunami. Given the massive investment required and lack of motivation to do it, there will be almost no prepa…
This will be a huge disaster, but our government and institutions are not apathetic to it.
1. https://www.newyorker.com/tech/annals-of-technology/how-to-s...
2. https://www.seattle.gov/Documents/Departments/Emergency/Plan...
3. https://www.fema.gov/press-release/20210318/emergency-manage... (a 2022 exercise is planned)
Earlier quoted context omitted.
That figure comes with a caveat that's mentioned towards the end of the article: > As for casualties: the figures I cited earlier—twenty-seven thousand injured, almost thirteen thousand dead—are based on the agency’s official planning scenario, which has the earthquake striking at 9:41 A.M. on February 6th. If, instead, it strikes in the summer, when the beaches are full, those numbers could be off by a horrifying ma…
If this is the case, it seems like you could get a lot of bang for your buck by building up a beach evacuation infrastructure.
In this sample evacuation map for Ocean City WA, the higher ground is within half a mile of a good chunk of the coast, and nearly all of the coast is a mile from higher ground. https://www.dnr.wa.gov/Publications/ger_tsunami_evac_oceanci...
Earlier quoted context omitted.
I don’t know about how this would impact the estimates, but the Pacific Northwest differs from Japan in that the largest population centers — Vancouver, Seattle, Portland — are not exposed to the open ocean.
Seattle also rises very quickly from the ocean. Take a look: https://en-us.topographic-map.com/maps/na3/Seattle/ With the exception of the international district, all the low-lying areas are industrial in nature.