26 ms·

1700 Cascadia Earthquake

132 points by Hooke 5y ago

bmmayer1 5y ago
Would not be complete without this fantastic article: https://www.newyorker.com/magazine/2015/07/20/the-really-big-one https://www.newyorker.com/magazine/2015/07/20/the-really-big...
- pmontra 5y ago
  And Peter Watts' Starfish, from the web site of the author https://www.rifters.com/real/STARFISH.htm https://www.rifters.com/real/STARFISH.htm That's the next earthquake.
  - interestica 5y ago
    And Pacific Northwest Seismic Network blog https://pnsn.org/blog/2020/01/27/getting-ready-for-the-next-great-cascadia-subduction-zone-earthquake https://pnsn.org/blog/2020/01/27/getting-ready-for-the-next-...
- gxqoz 5y ago
  Fun song by Tacocat inspired by this article: https://www.youtube.com/watch?v=DJH1WKSugNo https://www.youtube.com/watch?v=DJH1WKSugNo I saw them perform it at a concert in front of the Space Needle. Really felt I was tempting fate there.
  - nowandlater 5y ago
    That Jazz Bass is so damn minty fresh; honestly, you're pretty lucky that alone didn't cause the big one!
- RcouF1uZ4gsC 5y ago
  From that article: > fema projects that nearly thirteen thousand people will die in the Cascadia earthquake and tsunami. From the rest of the article, it seems that this estimate of deaths is too low by an order of magnitude. More people died in the Fukushima earthquake, and that is in a country that is probably the most earthquake ready country in the world. If you only have 15 minutes from the start of the earthquake to when the tsunami rolls in, given the density and the lack of preparation, I could easily see several 100 thousand people perishing if not a million.
  - divbzero 5y ago
    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.
    - deleted 5y ago
      [deleted]
    - ahelwer 5y ago
      Seattle also rises very quickly from the ocean. Take a look: https://en-us.topographic-map.com/maps/na3/Seattle/ 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.
      - jvolkman 5y ago
        "Drumlin" is the fun word for this geology, from what I understand. https://youtu.be/oSSxdogrv1s?t=189 https://youtu.be/oSSxdogrv1s?t=189
    - markkanof 5y ago
      Right, in Oregon the coastal areas mostly rise quite quickly from the beach and are relatively sparsely populated. The more populated areas of Portland, Salem, Eugene, etc are well away from the ocean, so a tsunami is unlikely to kill very many people here.
  - tomtheelder 5y ago
    The population isn't really coastal. There will be a lot of casualties along the coast, but it is sparsely populated. The overall number should be much lower than the Tohoku quake. Some other estimates have the number considerably lower than FEMA's.
  - akiselev 5y ago
    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 margin. Thirteen thousand sounds like a best case scenario. If it happens 4th of July weekend when a million people are on the beaches all up and down the west coast, that could cause orders of magnitude more fatalities.
- gammarator 5y ago
  I think that article is best paired with this followup: https://www.newyorker.com/tech/annals-of-technology/how-to-stay-safe-when-the-big-one-comes 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 important thing to note about that remark is that, needless to say, Murphy really said it, and stood by it in the fact-checking process—so, clearly, fema is anticipating that the region will be in very grave shape. > That said, “toast” is not what you would call a precise description, so let me be more specific. What Murphy did not mean is that everyone west of I-5 will be injured or killed; fema’s casualty figures, while horrifying, amount to under one-half of one per cent of the population of the region. Nor did he mean that every structure west of the interstate will fail
  - throwawaw 5y ago
    For God's sake, just quote the whole thing. You really broke it off mid-sentence? 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.
  - irrational 5y ago
    I live in the Portland area, west of I-5. The reason for this became clear when I saw this article (which I learned about here on HN): https://www.usgs.gov/news/volcanoes-vineyards-new-geologic-map-reveals-portlands-deep-history https://www.usgs.gov/news/volcanoes-vineyards-new-geologic-m... For instance, look at page 3 of the pamphlet: https://pubs.usgs.gov/sim/3443/sim3443_pamphlet.pdf https://pubs.usgs.gov/sim/3443/sim3443_pamphlet.pdf To the west of Portland we see Dark Gray which is Basalt (if you've ever driven through the tunnel and up and over the west hills to the western suburbs of Portland, you have driven through the basalt region) and then there is a big light yellow oval that is labelled Tualatin Basin. What is the light yellow according to the legend? It is surface deposits. Long ago this was a basalt bowl. Then a giant flood came down the Columbia river gorge and dumped hundreds of feet of clay silt into the bowl. When you are standing in Beaverton, Hillsboro, Bethany, etc. you are standing hundreds of feet above the original valley floor. Now look at the map again. The basin is pretty much all to the west of I-5. If you live in the basin you are screwed when the big earthquake hits (the one exception is that hill of basalt rising like an island in the middle of the basin - that is Cooper Mountain, it's no coincidence that the houses on top of Cooper Mountain are where the rich people live). What is going to happen is the earthquake waves will come in and bounce off the basalt on one side of the bowl and reverberate back to the basalt on the other side. The waves will go back and forth in the bowl and liquefy all of that old clay silt. Just like this: https://www.youtube.com/watch?v=3NSXmTfASM0 https://www.youtube.com/watch?v=3NSXmTfASM0
- deleted 5y ago
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- philshem 5y ago
  It's a fantastic article, which also won Kathryn Schulz and the New Yorker a Pulitzer! https://www.oregonlive.com/today/2016/04/really_big_one_pulitzer_new_yorker.html https://www.oregonlive.com/today/2016/04/really_big_one_puli... https://www.pulitzer.org/winners/kathryn-schulz https://www.pulitzer.org/winners/kathryn-schulz
meepmorp 5y ago
And for our European readers: https://en.wikipedia.org/wiki/1755_Lisbon_earthquake https://en.wikipedia.org/wiki/1755_Lisbon_earthquake
- flobosg 5y ago
  Around the same time, in Chile: https://en.wikipedia.org/wiki/1730_Valpara%C3%ADso_earthquake https://en.wikipedia.org/wiki/1730_Valpara%C3%ADso_earthquak... https://en.wikipedia.org/wiki/1751_Concepci%C3%B3n_earthquake https://en.wikipedia.org/wiki/1751_Concepci%C3%B3n_earthquak...
thedigitalone 5y ago
"Our operating assumption is that everything west of Interstate 5 will be toast." Ouch.
- adrianpike 5y ago
  It's a great soundbite, but it loses a lot of context when distilled down. Most of the infill west of I5 in the Seattle area will probably liquefy, but there's mountain ranges to the west of I5 that would take a hell of a quake to toast.
  - blacksmith_tb 5y ago
    Yes, I have assumed they meant something more specific, like "every building and road west of I5" (I live only a few miles east, so I doubt I'd be unscathed myself, somehow).
  - vmception 5y ago
    The earth will be fine its the humans we are worried about Specifically, the perpetual habitability for humans
  - eloff 5y ago
    Anything low lying in that area is at high risk in a cascadia quake. Buildings on high ground "only" have the quake risk, which is still significant.
    - JALTU 5y ago
      I'm more concerned about the homes that will go up in flames due to ruptured gas lines. With the fire department overwhelmed, the potential amount of toxic smoke/fumes post-quake scares me more than the quake. Assuming I survive, assuming my family/friends do, assuming we all even are happy about being survivors of something so colossal, at such scale...
      - eloff 5y ago
supernova87a 5y ago
I love how some cultures have recordkeeping that goes back hundreds of years that can be tied to explain some unusual sediment deposits found halfway around the world.
- kibwen 5y ago
  Nearby this in Oregon is Crater Lake, which is the stunning remnant of a catastrophic volcanic eruption 7,700 years ago. The volcanic explosivity index classifies it as a 7, "super-colossal", i.e. an order of magnitude larger than Krakatoa. And indeed there are Native American tribes who have passed down the story of the eruption over the millennia, believing it to be the site of a battle between gods. Super cool to see folklore and geology intersect.
  - ggreer 5y ago
    I'm pretty sure these intersections are often coincidence. There are enough myths across enough cultures that you're bound to find some with similarities to real events. For example: if the story of Sodom and Gomorrah had been a Klamath myth instead of a Hebrew myth, people would claim that it was from the eruption of Crater Lake. The same goes for pretty much any prehistoric flood.[1] 1. https://en.wikipedia.org/wiki/Flood_myth https://en.wikipedia.org/wiki/Flood_myth
    - ncmncm 5y ago
      There really was a worldwide flood. It did not recede; all the water is still there. Instead, people had to abandon where they lived and move uphill. It didn't happen all in one day, or year. But there were many places where the water moved inland by three feet per year; any beach one knew as a child was gone by adulthood. Millions of square miles of what was lowland is now underwater -- the region between Indonesian islands; for hundreds of miles out to sea from Viet Nam all the way up to Korea; all the space between Australia and New Guinea; thousands of square miles off India; the whole Persian Gulf; England and Ireland were not islands; from Florida to Louisiana; from Argentina out to the Falklands. These places were prime habitat (possibly excepting near the Falklands, and northern England), so not unpopulated. It seems significant that the oldest known civilizations, in Mesopotamia and the Indus valley, arose immediately uphill from especially major inundations. Australian oral records have precise accounts of conflict resolutions over people moving uphill into land already occupied for 40,000+ years.
gammarator 5y ago
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://mil.wa.gov/alerts
- interestica 5y ago
  ...and British Columbia did its first test of its public alert system today. (Cell/LTE based). Timely?
- cvdub 5y ago
  > Washington deployed the ShakeAlert earthquake early warning system just yesterday Do you know how the early warning system works? How much advance warning do they expect to give?
  - hadlock 5y ago
    Tokyo got nearly 30 seconds warning for the Fukushima earthquake. I have no idea how well Washington's system works, but I would imagine that someday it'll be as good as Japan's was in 2011
    - xucheng 5y ago
      In order for this happens, we really need an unified earthquake early warning network in entire west coast connecting from BC, Canada all the way to Mexico. It seems that all the existing systems are only regional so far. At the same time, we probably need to drastically increase the density of the seismometers. All in all, the earthquake early warning system in North America still lies far behind to say the system in Japan.
  - goodcanadian 5y ago
    The Earthquake warning system works through the fact that the signal travels faster than the ground waves. So, earthquake occurs and is detected. A warning is sent out. The amount of time between the warning and when you feel shaking is entirely dependent on how far you are from the epicentre. It won't give you much time, but it should be enough to get under a table, or to move away from windows that could break or things that could fall on you.
kyledrake 5y ago
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 preparation in advance. It is not unreasonable to predict it will be the biggest natural disaster in American history by orders of magnitude. Here is the best attempt I've seen so far to novelize what will happen in Portland. While obviously speculative, it's all very much based on the evidence at the time and I think does a better job of describing what will happen than just reading the dry (and usually incorrect because they assume supporting infrastructure) reports from the utility companies on how long they think it will take to, for example, repair the transmission lines. If you live in Portland, I implore you to sit down for an evening and take the time to digest this: https://www.vice.com/en/article/8q8gyx/first-five-minutes-big-one-earthquake https://www.vice.com/en/article/8q8gyx/first-five-minutes-bi... Don't panic, but take this seriously, this is a scientifically verified thing that will happen. It is never too early to consider things like earthquake retrofitting your home (bolting the frame to the foundation) and preparing emergency supplies like properly stored food and water. If you're on the coast, memorize your escape route, you won't have time to look it up and your phone won't work anyways.
- metatation 5y ago
  I recently listened to the excellent "Fault Lines"[0] podcast from CBC podcast by seismologist Johanna Wagstaffe. It describes the anticipated impact of the impending megathrust earthquake by examining the first moments, hours, days, etc after the event. [0] https://www.cbc.ca/listen/cbc-podcasts/147-fault-lines https://www.cbc.ca/listen/cbc-podcasts/147-fault-lines
- connor4312 5y ago
  This is a little pessimistic.[1] As a percentage, few people are expected to die, and modern buildings are unlikely to collapse. At least in the Puget Sound region, buildings codes have been seismically sound for several decades, and old buildings and infrastructure have gradually been retrofitted[2]. There is _already_ preparation being made with the aforementioned programs, and notably the Cascadia Rising simulation excercise carried out between the Washington and Oregon governments and FEMA.[3] 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-stay-safe-when-the-big-one-comes https://www.newyorker.com/tech/annals-of-technology/how-to-s... 2. https://www.seattle.gov/Documents/Departments/Emergency/PlansOEM/SHIVA/2014-04-23_Earthquakes(0).pdf https://www.seattle.gov/Documents/Departments/Emergency/Plan... 3. https://www.fema.gov/press-release/20210318/emergency-managers-announce-improvements-after-cascadia-rising-exercise https://www.fema.gov/press-release/20210318/emergency-manage... (a 2022 exercise is planned)
lowbloodsugar 5y ago
The biggest ones (>8.5) are on average every 500 years. Timeline: https://projects.oregonlive.com/maps/earthquakes/timeline https://projects.oregonlive.com/maps/earthquakes/timeline
- ncmncm 5y ago
  So if we are super-lucky, it will happen in this century, and be smaller.
Pfhreak 5y ago
Add onto this that many or most of the mountains in the area are active volcanoes that are overdue for an eruption, and the Seattle area could be in for a real bad time over the next 250 years. The projections of a moderate eruption of Mount Rainier (aka Tahoma/Tacoma) include flows reaching all the way to Renton/South Seattle.
- doktorhladnjak 5y ago
  “Most” of the mountains are not active volcanos. There are only 4 in Washington: Baker, Rainier, St Helens, Adams but hundreds of other mountains. Rainier is really the only one that poses serious danger to a populated area. Tacoma in particular will be destroyed by lahars alone in a large eruption
  - jandrewrogers 5y ago
    There are (at least) five major active volcanoes in Washington. You are forgetting Glacier Peak, an active volcano that is as close to Seattle as Rainier, but not as visible due to its lower elevation.
- hodgesrm 5y ago
  I have not seen anything that indicates Rainier or other volcanos are "overdue" for an eruption. Rainier, like others, goes through periods of greater or lesser activity. It's hard to predict the size of any particular eruption, as we saw at Mt St. Helens in 1980. The biggest risk from Rainier currently is lahars, aka mudflows. You don't need an eruption for those. The last big one was Kautz Creek in 1947. If you live in one of the valleys around Rainier there's a reasonable chance of seeing a lahar in your lifetime. (Hopefully from somewhere out of harm's way.)
Pfhreak 5y ago
Reminder to folks that water, food, blankets, and tools are reasonable things to have stored away if you live in the PNW (or anywhere, really), and are relatively low maintenance to store.
ZDurmPhoto 5y ago
I live in Portland and have a slide-in truck camper on my property. I use it for camping of course, but it is also part of my earthquake preparation plan. It is solar powered but also has a built-in propane generator. It is fully self-contained with all the comforts of home including fresh water storage, a galley with oven, stove, freezer and fridge. A bathroom plus a hot shower, comfortable bed, large pantry, closet, etc. It sits on a 3500 diesel truck that can go just about anywhere. I know this solution is not practical for everyone. But it is always fully fueled, fully stocked and offers considerable peace of mind. If you have been on the fence about buying an RV, think of it from this angle.
- Spooky23 5y ago
  This type of stuff is what always made the west coast unappealing. Where I live, disaster is a bad ice storm, blizzard or localized flooding. Complete devastation just isn’t my thing.
  - tjr225 5y ago
    I wish it kept more people away.
  - irrational 5y ago
    Yeah, but this isn't like living in Tornado alley or the east coast where there is a hurricane season. I live in Portland and we don't have any natural disasters unless a major earthquake does happen or a volcano comes to life. But let's be realistic, what are the chances of that happening in our lifetimes? It's not like this is an every year thing like tornadoes, hurricanes, blizzards, etc. Complete devastation from hurricanes and tornadoes and flooding is much more likely than huge earthquakes and volcanoes.
    - ghaff 5y ago
      Tornadoes are pretty rare (and localized) outside of certain areas. Blizzards--other than a bad one if you live on the coast--are mostly a stay at home until it's over event. Hurricanes/floods are definitely in the southeast and can come up the coast as in Sandy. But this again mostly involves having a house somewhere that's not overly exposed to flooding if there's a lot of rain. But yes. There's some balancing of unlikely but major natural disasters and fairly routine bad weather events. From a natural disaster perspective you're probably best off in the desert Southwest.
tbeutel 5y ago
There's been quite a bit of tremor activity in the last month. I don't know if it is a change from before, but over the last month (2021-04-01 - 2021-05-06) basically everything west of I-5 from Portland, OR to Redding, CA has had deep tremors. https://pnsn.org/tremor?starttime=2021-04-01T00:00:00&endtime=2021-05-06T23:59:59&coloring=red&magnitude=false https://pnsn.org/tremor?starttime=2021-04-01T00:00:00&endtim...
breakyerself 5y ago
Here is an excellent lecture on the subject from CWU professor Nick Zenter. If you watch this there is a good chance you'll decide to watch all of his lecture on the channel. Very enthralling. https://youtu.be/UJ7Qc3bsxjI https://youtu.be/UJ7Qc3bsxjI
- tresil 5y ago
  Nick’s geology talks are a near-perfect mix of academic science, and dynamic storytelling.
- valleyjo 5y ago
  Love Nick Zenter! He has a great podcast too! I’d love to see his talks in person one day.
- e40 5y ago
  I watched this yesterday. It was quite interesting.
rconti 5y ago
I remember in early 2001, reading an article in the NYTimes or Seattle Times about the quake risk in Seattle, showing an easterly view of downtown from Puget Sound. In it, a line was drawn, showing a fault line, just about 4 blocks south of the Kingdome/Safeco Field area, along with the usual panic about how bad an earthquake could be in the region. This article and that image flashed through my mind when not more than a few weeks later, I found myself sitting on the 4th and uppermost floor of a 100+ year old brick building, precisely where that fault line was drawn, as the floor started bouncing, then swaying, then the ceiling lamps were swinging back and forth so violently that they were hitting the ceiling on either side, and interior brick walls started to give way. I worked in that building for another year and a half after that February 2001 6.8 magnitude Nisqually Quake[1], and every time a truck bounced down the potholes of 1st Avenue South, and the office floor bounced, my palms would sweat. [1] https://en.wikipedia.org/wiki/2001_Nisqually_earthquake https://en.wikipedia.org/wiki/2001_Nisqually_earthquake
- bombcar 5y ago
  California gets hit with earthquakes quite often, and so has been made more resilient. When a big one hits Seattle or the Midwest is when you’ll see untold damage. Just compare bridge pillars in various parts of the country.
  - shkkmo 5y ago
    When the "big one" hits the pacific NW, bridge design is not going to save significant areas from complete destruction. I am talking about the Cascadian Subduction Zone letting go which happens every 200 to 1200 years (41 times in the last 10000 years). The last time this happened, in 1700, there was a 9.0 earthquake, a 100 foot tsunami and the coastline dropped several feet. There is about a ~10% chance this will happen again in the next 50 years. If it does, large areas will be completely unprepared and a very large number of people will die.
    - geocrasher 5y ago
      Not to mention that a very large number of homes in Western Washington are at least 80 years old. The house I live in was built in 1919. It's wood construction and has been gutted/remodeled, but it's also been added onto at least once and has no real foundation, but I think it might be a pier and beam type. An earthquake of large size, 7.0+ will probably cause major damage. For reference, I live near Chehalis, WA.
29athrowaway 5y ago
The strongest earthquakes in recent history (1906-2005): 1. https://en.wikipedia.org/wiki/1960_Valdivia_earthquake https://en.wikipedia.org/wiki/1960_Valdivia_earthquake 2. https://en.wikipedia.org/wiki/1964_Alaska_earthquake https://en.wikipedia.org/wiki/1964_Alaska_earthquake 3. https://en.wikipedia.org/wiki/2004_Indian_Ocean_earthquake_and_tsunami https://en.wikipedia.org/wiki/2004_Indian_Ocean_earthquake_a... Those 3 amount for over 50% of all the energy released by earthquakes in that period. https://upload.wikimedia.org/wikipedia/commons/7/79/Graph_of_largest_earthquakes_1906-2005.png https://upload.wikimedia.org/wikipedia/commons/7/79/Graph_of... There's this one too: https://en.wikipedia.org/wiki/2011_T%C5%8Dhoku_earthquake_and_tsunami https://en.wikipedia.org/wiki/2011_T%C5%8Dhoku_earthquake_an...
- longemen3000 5y ago
  I was near the epicenter of the Chilean earthquake of 2010 (8.8),and my grandfather was in the 1960 one. The main mayority of the casualties in both earthquakes were caused by tsunamis (its really a bummer that Chile is basically a long strip of coast) we were lucky (in 2010)because the nearest big coastal population center was inside a bay, so the wave didn't hit directly. the 1960 earthquake has a very interesting history, one day before (Saturday) , there was one big earthquake(8 1-8.3, X in mercalli m) 400 km North (city of Concepción) , that cut the communications and roadways from the capital to the south of the country. On Sunday, a second earthquake of similar magnitude struck, that finished destroying the remaining buildings in the location,but nobody died on that second earthquake because everyone was outside,for obvious reasons. Finally, the big one started not on Valdivia (300 km South) but the fault line extended 1000 km reaching Valdivia and beyond, 135 people died on Japan, Valdivia itself sunk permanently 2.7 meters (8 feet) ,one chain of lakes got their exit rivers blocked, so the water level was rising rapidly and if overflowed, it would flood again the same areas affected by the earthquake, so a joint operation between military and private parties were set up to try to unblock the whole system (they succeeded), there was a case of human sacrifice, trying to calm the fury of the gods that caused such destruction, it was wild
  - 29athrowaway 5y ago
    Most of the destruction in the 2010 Chile Earthquake was caused by people themselves: looting, arson and violence. The Bachelet administration was hesitant to mobilize the army due to the potential political cost (i.e.: bringing back memories of the Pinochet regime), so they took several days to make that decision and in the meantime things went completely out of control. The same administration was also hesitant to evacuate the residents in the Juan Fernandez Islands, effectively causing many of them to die when the tsunami wave hit.
lwansbrough 5y ago
I live on the 8th floor of an old 60's Vancouver 18-story apartment complex. I'd like to be out of here sooner than later, as I suspect this building and many like it will simply collapse entirely when the big one hits. Similar, erm, paranoia is why I would never purchase in Richmond/Delta. Liquefaction of that entire region is possible - not something I like to think about!
dave333 5y ago
Maybe they should build some large reinforced concrete buildings that can act as tsunami shelters and also fulfil a secondary function such as public library (do they still have those) or offices/shops or whatever. Maybe 100 ft high would be enough, but design it so that people can survive inside it even if it is temporarily overrun by the tsunami. Or you could build a larger number of small reinforced shelters that would be designed to be overrun but would keep people alive until the tsunami retreats.
- irrational 5y ago
  They don't need this along Cascadia. All of the major population centers are 60 miles inland (in between the coastal and cascade mountain ranges). There are just very small town on the coasts and the coastal mountain range rises very quickly from the coast. You can get to high ground from just about anywhere on the coast fairly quickly.
arethuza 5y ago
There is a fantastic set of videos on the geology of the Pacific Northwest by Nick Zentner available on Youtube: https://www.youtube.com/playlist?list=PLpwTojTevrmOfXmPVpGSa3UcKC_Lg5oVM https://www.youtube.com/playlist?list=PLpwTojTevrmOfXmPVpGSa... Edit: I'm nowhere near the area (I'm in Scotland) but I find the series absolutely fascinating.
- jmcqk6 5y ago
  Zentner's videos are forking fantastic. There is some really mind blowing stuff about the PNW geology. For example, Did you know there's a connection between Yellowstone, Smith Rock in Oregon, and Liberty Gold in central Washington? The possible connections between columbia river basalt and yellowstone is also very interesting. It's just a fantastic place to be for geology.

132 points by Hooke 5y ago

Would not be complete without this fantastic article: https://www.newyorker.com/magazine/2015/07/20/the-really-big-one https://www.newyorker.com/magazine/2015/07/20/the-really-big...

pmontra 5y ago
And Peter Watts' Starfish, from the web site of the author https://www.rifters.com/real/STARFISH.htm https://www.rifters.com/real/STARFISH.htm That's the next earthquake.
- interestica 5y ago
  And Pacific Northwest Seismic Network blog https://pnsn.org/blog/2020/01/27/getting-ready-for-the-next-great-cascadia-subduction-zone-earthquake https://pnsn.org/blog/2020/01/27/getting-ready-for-the-next-...
gxqoz 5y ago
Fun song by Tacocat inspired by this article: https://www.youtube.com/watch?v=DJH1WKSugNo https://www.youtube.com/watch?v=DJH1WKSugNo I saw them perform it at a concert in front of the Space Needle. Really felt I was tempting fate there.
- nowandlater 5y ago
  That Jazz Bass is so damn minty fresh; honestly, you're pretty lucky that alone didn't cause the big one!
RcouF1uZ4gsC 5y ago
From that article: > fema projects that nearly thirteen thousand people will die in the Cascadia earthquake and tsunami. From the rest of the article, it seems that this estimate of deaths is too low by an order of magnitude. More people died in the Fukushima earthquake, and that is in a country that is probably the most earthquake ready country in the world. If you only have 15 minutes from the start of the earthquake to when the tsunami rolls in, given the density and the lack of preparation, I could easily see several 100 thousand people perishing if not a million.
- divbzero 5y ago
  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.
  - deleted 5y ago
    [deleted]
  - ahelwer 5y ago
    Seattle also rises very quickly from the ocean. Take a look: https://en-us.topographic-map.com/maps/na3/Seattle/ 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.
    - jvolkman 5y ago
      "Drumlin" is the fun word for this geology, from what I understand. https://youtu.be/oSSxdogrv1s?t=189 https://youtu.be/oSSxdogrv1s?t=189
  - markkanof 5y ago
    Right, in Oregon the coastal areas mostly rise quite quickly from the beach and are relatively sparsely populated. The more populated areas of Portland, Salem, Eugene, etc are well away from the ocean, so a tsunami is unlikely to kill very many people here.
- tomtheelder 5y ago
  The population isn't really coastal. There will be a lot of casualties along the coast, but it is sparsely populated. The overall number should be much lower than the Tohoku quake. Some other estimates have the number considerably lower than FEMA's.
- akiselev 5y ago
  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 margin. Thirteen thousand sounds like a best case scenario. If it happens 4th of July weekend when a million people are on the beaches all up and down the west coast, that could cause orders of magnitude more fatalities.
gammarator 5y ago
I think that article is best paired with this followup: https://www.newyorker.com/tech/annals-of-technology/how-to-stay-safe-when-the-big-one-comes 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 important thing to note about that remark is that, needless to say, Murphy really said it, and stood by it in the fact-checking process—so, clearly, fema is anticipating that the region will be in very grave shape. > That said, “toast” is not what you would call a precise description, so let me be more specific. What Murphy did not mean is that everyone west of I-5 will be injured or killed; fema’s casualty figures, while horrifying, amount to under one-half of one per cent of the population of the region. Nor did he mean that every structure west of the interstate will fail
- throwawaw 5y ago
  For God's sake, just quote the whole thing. You really broke it off mid-sentence? 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.
- irrational 5y ago
  I live in the Portland area, west of I-5. The reason for this became clear when I saw this article (which I learned about here on HN): https://www.usgs.gov/news/volcanoes-vineyards-new-geologic-map-reveals-portlands-deep-history https://www.usgs.gov/news/volcanoes-vineyards-new-geologic-m... For instance, look at page 3 of the pamphlet: https://pubs.usgs.gov/sim/3443/sim3443_pamphlet.pdf https://pubs.usgs.gov/sim/3443/sim3443_pamphlet.pdf To the west of Portland we see Dark Gray which is Basalt (if you've ever driven through the tunnel and up and over the west hills to the western suburbs of Portland, you have driven through the basalt region) and then there is a big light yellow oval that is labelled Tualatin Basin. What is the light yellow according to the legend? It is surface deposits. Long ago this was a basalt bowl. Then a giant flood came down the Columbia river gorge and dumped hundreds of feet of clay silt into the bowl. When you are standing in Beaverton, Hillsboro, Bethany, etc. you are standing hundreds of feet above the original valley floor. Now look at the map again. The basin is pretty much all to the west of I-5. If you live in the basin you are screwed when the big earthquake hits (the one exception is that hill of basalt rising like an island in the middle of the basin - that is Cooper Mountain, it's no coincidence that the houses on top of Cooper Mountain are where the rich people live). What is going to happen is the earthquake waves will come in and bounce off the basalt on one side of the bowl and reverberate back to the basalt on the other side. The waves will go back and forth in the bowl and liquefy all of that old clay silt. Just like this: https://www.youtube.com/watch?v=3NSXmTfASM0 https://www.youtube.com/watch?v=3NSXmTfASM0
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philshem 5y ago
It's a fantastic article, which also won Kathryn Schulz and the New Yorker a Pulitzer! https://www.oregonlive.com/today/2016/04/really_big_one_pulitzer_new_yorker.html https://www.oregonlive.com/today/2016/04/really_big_one_puli... https://www.pulitzer.org/winners/kathryn-schulz https://www.pulitzer.org/winners/kathryn-schulz

meepmorp 5y ago

And for our European readers: https://en.wikipedia.org/wiki/1755_Lisbon_earthquake https://en.wikipedia.org/wiki/1755_Lisbon_earthquake

flobosg 5y ago
Around the same time, in Chile: https://en.wikipedia.org/wiki/1730_Valpara%C3%ADso_earthquake https://en.wikipedia.org/wiki/1730_Valpara%C3%ADso_earthquak... https://en.wikipedia.org/wiki/1751_Concepci%C3%B3n_earthquake https://en.wikipedia.org/wiki/1751_Concepci%C3%B3n_earthquak...

thedigitalone 5y ago

"Our operating assumption is that everything west of Interstate 5 will be toast." Ouch.

adrianpike 5y ago
It's a great soundbite, but it loses a lot of context when distilled down. Most of the infill west of I5 in the Seattle area will probably liquefy, but there's mountain ranges to the west of I5 that would take a hell of a quake to toast.
- blacksmith_tb 5y ago
  Yes, I have assumed they meant something more specific, like "every building and road west of I5" (I live only a few miles east, so I doubt I'd be unscathed myself, somehow).
- vmception 5y ago
  The earth will be fine its the humans we are worried about Specifically, the perpetual habitability for humans
- eloff 5y ago
  Anything low lying in that area is at high risk in a cascadia quake. Buildings on high ground "only" have the quake risk, which is still significant.
  - JALTU 5y ago
    I'm more concerned about the homes that will go up in flames due to ruptured gas lines. With the fire department overwhelmed, the potential amount of toxic smoke/fumes post-quake scares me more than the quake. Assuming I survive, assuming my family/friends do, assuming we all even are happy about being survivors of something so colossal, at such scale...
    - eloff 5y ago

supernova87a 5y ago

I love how some cultures have recordkeeping that goes back hundreds of years that can be tied to explain some unusual sediment deposits found halfway around the world.

kibwen 5y ago
Nearby this in Oregon is Crater Lake, which is the stunning remnant of a catastrophic volcanic eruption 7,700 years ago. The volcanic explosivity index classifies it as a 7, "super-colossal", i.e. an order of magnitude larger than Krakatoa. And indeed there are Native American tribes who have passed down the story of the eruption over the millennia, believing it to be the site of a battle between gods. Super cool to see folklore and geology intersect.
- ggreer 5y ago
  I'm pretty sure these intersections are often coincidence. There are enough myths across enough cultures that you're bound to find some with similarities to real events. For example: if the story of Sodom and Gomorrah had been a Klamath myth instead of a Hebrew myth, people would claim that it was from the eruption of Crater Lake. The same goes for pretty much any prehistoric flood.[1] 1. https://en.wikipedia.org/wiki/Flood_myth https://en.wikipedia.org/wiki/Flood_myth
  - ncmncm 5y ago
    There really was a worldwide flood. It did not recede; all the water is still there. Instead, people had to abandon where they lived and move uphill. It didn't happen all in one day, or year. But there were many places where the water moved inland by three feet per year; any beach one knew as a child was gone by adulthood. Millions of square miles of what was lowland is now underwater -- the region between Indonesian islands; for hundreds of miles out to sea from Viet Nam all the way up to Korea; all the space between Australia and New Guinea; thousands of square miles off India; the whole Persian Gulf; England and Ireland were not islands; from Florida to Louisiana; from Argentina out to the Falklands. These places were prime habitat (possibly excepting near the Falklands, and northern England), so not unpopulated. It seems significant that the oldest known civilizations, in Mesopotamia and the Indus valley, arose immediately uphill from especially major inundations. Australian oral records have precise accounts of conflict resolutions over people moving uphill into land already occupied for 40,000+ years.

gammarator 5y ago

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://mil.wa.gov/alerts

interestica 5y ago
...and British Columbia did its first test of its public alert system today. (Cell/LTE based). Timely?
cvdub 5y ago
> Washington deployed the ShakeAlert earthquake early warning system just yesterday Do you know how the early warning system works? How much advance warning do they expect to give?
- hadlock 5y ago
  Tokyo got nearly 30 seconds warning for the Fukushima earthquake. I have no idea how well Washington's system works, but I would imagine that someday it'll be as good as Japan's was in 2011
  - xucheng 5y ago
    In order for this happens, we really need an unified earthquake early warning network in entire west coast connecting from BC, Canada all the way to Mexico. It seems that all the existing systems are only regional so far. At the same time, we probably need to drastically increase the density of the seismometers. All in all, the earthquake early warning system in North America still lies far behind to say the system in Japan.
- goodcanadian 5y ago
  The Earthquake warning system works through the fact that the signal travels faster than the ground waves. So, earthquake occurs and is detected. A warning is sent out. The amount of time between the warning and when you feel shaking is entirely dependent on how far you are from the epicentre. It won't give you much time, but it should be enough to get under a table, or to move away from windows that could break or things that could fall on you.

kyledrake 5y ago

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 preparation in advance. It is not unreasonable to predict it will be the biggest natural disaster in American history by orders of magnitude. Here is the best attempt I've seen so far to novelize what will happen in Portland. While obviously speculative, it's all very much based on the evidence at the time and I think does a better job of describing what will happen than just reading the dry (and usually incorrect because they assume supporting infrastructure) reports from the utility companies on how long they think it will take to, for example, repair the transmission lines. If you live in Portland, I implore you to sit down for an evening and take the time to digest this: https://www.vice.com/en/article/8q8gyx/first-five-minutes-big-one-earthquake https://www.vice.com/en/article/8q8gyx/first-five-minutes-bi... Don't panic, but take this seriously, this is a scientifically verified thing that will happen. It is never too early to consider things like earthquake retrofitting your home (bolting the frame to the foundation) and preparing emergency supplies like properly stored food and water. If you're on the coast, memorize your escape route, you won't have time to look it up and your phone won't work anyways.

metatation 5y ago
I recently listened to the excellent "Fault Lines"[0] podcast from CBC podcast by seismologist Johanna Wagstaffe. It describes the anticipated impact of the impending megathrust earthquake by examining the first moments, hours, days, etc after the event. [0] https://www.cbc.ca/listen/cbc-podcasts/147-fault-lines https://www.cbc.ca/listen/cbc-podcasts/147-fault-lines
connor4312 5y ago
This is a little pessimistic.[1] As a percentage, few people are expected to die, and modern buildings are unlikely to collapse. At least in the Puget Sound region, buildings codes have been seismically sound for several decades, and old buildings and infrastructure have gradually been retrofitted[2]. There is _already_ preparation being made with the aforementioned programs, and notably the Cascadia Rising simulation excercise carried out between the Washington and Oregon governments and FEMA.[3] 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-stay-safe-when-the-big-one-comes https://www.newyorker.com/tech/annals-of-technology/how-to-s... 2. https://www.seattle.gov/Documents/Departments/Emergency/PlansOEM/SHIVA/2014-04-23_Earthquakes(0).pdf https://www.seattle.gov/Documents/Departments/Emergency/Plan... 3. https://www.fema.gov/press-release/20210318/emergency-managers-announce-improvements-after-cascadia-rising-exercise https://www.fema.gov/press-release/20210318/emergency-manage... (a 2022 exercise is planned)

lowbloodsugar 5y ago

The biggest ones (>8.5) are on average every 500 years. Timeline: https://projects.oregonlive.com/maps/earthquakes/timeline https://projects.oregonlive.com/maps/earthquakes/timeline

ncmncm 5y ago
So if we are super-lucky, it will happen in this century, and be smaller.

Pfhreak 5y ago

Add onto this that many or most of the mountains in the area are active volcanoes that are overdue for an eruption, and the Seattle area could be in for a real bad time over the next 250 years. The projections of a moderate eruption of Mount Rainier (aka Tahoma/Tacoma) include flows reaching all the way to Renton/South Seattle.

doktorhladnjak 5y ago
“Most” of the mountains are not active volcanos. There are only 4 in Washington: Baker, Rainier, St Helens, Adams but hundreds of other mountains. Rainier is really the only one that poses serious danger to a populated area. Tacoma in particular will be destroyed by lahars alone in a large eruption
- jandrewrogers 5y ago
  There are (at least) five major active volcanoes in Washington. You are forgetting Glacier Peak, an active volcano that is as close to Seattle as Rainier, but not as visible due to its lower elevation.
hodgesrm 5y ago
I have not seen anything that indicates Rainier or other volcanos are "overdue" for an eruption. Rainier, like others, goes through periods of greater or lesser activity. It's hard to predict the size of any particular eruption, as we saw at Mt St. Helens in 1980. The biggest risk from Rainier currently is lahars, aka mudflows. You don't need an eruption for those. The last big one was Kautz Creek in 1947. If you live in one of the valleys around Rainier there's a reasonable chance of seeing a lahar in your lifetime. (Hopefully from somewhere out of harm's way.)

Pfhreak 5y ago

Reminder to folks that water, food, blankets, and tools are reasonable things to have stored away if you live in the PNW (or anywhere, really), and are relatively low maintenance to store.

ZDurmPhoto 5y ago

I live in Portland and have a slide-in truck camper on my property. I use it for camping of course, but it is also part of my earthquake preparation plan. It is solar powered but also has a built-in propane generator. It is fully self-contained with all the comforts of home including fresh water storage, a galley with oven, stove, freezer and fridge. A bathroom plus a hot shower, comfortable bed, large pantry, closet, etc. It sits on a 3500 diesel truck that can go just about anywhere. I know this solution is not practical for everyone. But it is always fully fueled, fully stocked and offers considerable peace of mind. If you have been on the fence about buying an RV, think of it from this angle.

Spooky23 5y ago
This type of stuff is what always made the west coast unappealing. Where I live, disaster is a bad ice storm, blizzard or localized flooding. Complete devastation just isn’t my thing.
- tjr225 5y ago
  I wish it kept more people away.
- irrational 5y ago
  Yeah, but this isn't like living in Tornado alley or the east coast where there is a hurricane season. I live in Portland and we don't have any natural disasters unless a major earthquake does happen or a volcano comes to life. But let's be realistic, what are the chances of that happening in our lifetimes? It's not like this is an every year thing like tornadoes, hurricanes, blizzards, etc. Complete devastation from hurricanes and tornadoes and flooding is much more likely than huge earthquakes and volcanoes.
  - ghaff 5y ago
    Tornadoes are pretty rare (and localized) outside of certain areas. Blizzards--other than a bad one if you live on the coast--are mostly a stay at home until it's over event. Hurricanes/floods are definitely in the southeast and can come up the coast as in Sandy. But this again mostly involves having a house somewhere that's not overly exposed to flooding if there's a lot of rain. But yes. There's some balancing of unlikely but major natural disasters and fairly routine bad weather events. From a natural disaster perspective you're probably best off in the desert Southwest.

tbeutel 5y ago

There's been quite a bit of tremor activity in the last month. I don't know if it is a change from before, but over the last month (2021-04-01 - 2021-05-06) basically everything west of I-5 from Portland, OR to Redding, CA has had deep tremors. https://pnsn.org/tremor?starttime=2021-04-01T00:00:00&endtime=2021-05-06T23:59:59&coloring=red&magnitude=false https://pnsn.org/tremor?starttime=2021-04-01T00:00:00&endtim...

breakyerself 5y ago

Here is an excellent lecture on the subject from CWU professor Nick Zenter. If you watch this there is a good chance you'll decide to watch all of his lecture on the channel. Very enthralling. https://youtu.be/UJ7Qc3bsxjI https://youtu.be/UJ7Qc3bsxjI

tresil 5y ago
Nick’s geology talks are a near-perfect mix of academic science, and dynamic storytelling.
valleyjo 5y ago
Love Nick Zenter! He has a great podcast too! I’d love to see his talks in person one day.
e40 5y ago
I watched this yesterday. It was quite interesting.

rconti 5y ago

I remember in early 2001, reading an article in the NYTimes or Seattle Times about the quake risk in Seattle, showing an easterly view of downtown from Puget Sound. In it, a line was drawn, showing a fault line, just about 4 blocks south of the Kingdome/Safeco Field area, along with the usual panic about how bad an earthquake could be in the region. This article and that image flashed through my mind when not more than a few weeks later, I found myself sitting on the 4th and uppermost floor of a 100+ year old brick building, precisely where that fault line was drawn, as the floor started bouncing, then swaying, then the ceiling lamps were swinging back and forth so violently that they were hitting the ceiling on either side, and interior brick walls started to give way. I worked in that building for another year and a half after that February 2001 6.8 magnitude Nisqually Quake[1], and every time a truck bounced down the potholes of 1st Avenue South, and the office floor bounced, my palms would sweat. [1] https://en.wikipedia.org/wiki/2001_Nisqually_earthquake https://en.wikipedia.org/wiki/2001_Nisqually_earthquake

bombcar 5y ago
California gets hit with earthquakes quite often, and so has been made more resilient. When a big one hits Seattle or the Midwest is when you’ll see untold damage. Just compare bridge pillars in various parts of the country.
- shkkmo 5y ago
  When the "big one" hits the pacific NW, bridge design is not going to save significant areas from complete destruction. I am talking about the Cascadian Subduction Zone letting go which happens every 200 to 1200 years (41 times in the last 10000 years). The last time this happened, in 1700, there was a 9.0 earthquake, a 100 foot tsunami and the coastline dropped several feet. There is about a ~10% chance this will happen again in the next 50 years. If it does, large areas will be completely unprepared and a very large number of people will die.
  - geocrasher 5y ago
    Not to mention that a very large number of homes in Western Washington are at least 80 years old. The house I live in was built in 1919. It's wood construction and has been gutted/remodeled, but it's also been added onto at least once and has no real foundation, but I think it might be a pier and beam type. An earthquake of large size, 7.0+ will probably cause major damage. For reference, I live near Chehalis, WA.

29athrowaway 5y ago

The strongest earthquakes in recent history (1906-2005): 1. https://en.wikipedia.org/wiki/1960_Valdivia_earthquake https://en.wikipedia.org/wiki/1960_Valdivia_earthquake 2. https://en.wikipedia.org/wiki/1964_Alaska_earthquake https://en.wikipedia.org/wiki/1964_Alaska_earthquake 3. https://en.wikipedia.org/wiki/2004_Indian_Ocean_earthquake_and_tsunami https://en.wikipedia.org/wiki/2004_Indian_Ocean_earthquake_a... Those 3 amount for over 50% of all the energy released by earthquakes in that period. https://upload.wikimedia.org/wikipedia/commons/7/79/Graph_of_largest_earthquakes_1906-2005.png https://upload.wikimedia.org/wikipedia/commons/7/79/Graph_of... There's this one too: https://en.wikipedia.org/wiki/2011_T%C5%8Dhoku_earthquake_and_tsunami https://en.wikipedia.org/wiki/2011_T%C5%8Dhoku_earthquake_an...

longemen3000 5y ago
I was near the epicenter of the Chilean earthquake of 2010 (8.8),and my grandfather was in the 1960 one. The main mayority of the casualties in both earthquakes were caused by tsunamis (its really a bummer that Chile is basically a long strip of coast) we were lucky (in 2010)because the nearest big coastal population center was inside a bay, so the wave didn't hit directly. the 1960 earthquake has a very interesting history, one day before (Saturday) , there was one big earthquake(8 1-8.3, X in mercalli m) 400 km North (city of Concepción) , that cut the communications and roadways from the capital to the south of the country. On Sunday, a second earthquake of similar magnitude struck, that finished destroying the remaining buildings in the location,but nobody died on that second earthquake because everyone was outside,for obvious reasons. Finally, the big one started not on Valdivia (300 km South) but the fault line extended 1000 km reaching Valdivia and beyond, 135 people died on Japan, Valdivia itself sunk permanently 2.7 meters (8 feet) ,one chain of lakes got their exit rivers blocked, so the water level was rising rapidly and if overflowed, it would flood again the same areas affected by the earthquake, so a joint operation between military and private parties were set up to try to unblock the whole system (they succeeded), there was a case of human sacrifice, trying to calm the fury of the gods that caused such destruction, it was wild
- 29athrowaway 5y ago
  Most of the destruction in the 2010 Chile Earthquake was caused by people themselves: looting, arson and violence. The Bachelet administration was hesitant to mobilize the army due to the potential political cost (i.e.: bringing back memories of the Pinochet regime), so they took several days to make that decision and in the meantime things went completely out of control. The same administration was also hesitant to evacuate the residents in the Juan Fernandez Islands, effectively causing many of them to die when the tsunami wave hit.

lwansbrough 5y ago

I live on the 8th floor of an old 60's Vancouver 18-story apartment complex. I'd like to be out of here sooner than later, as I suspect this building and many like it will simply collapse entirely when the big one hits. Similar, erm, paranoia is why I would never purchase in Richmond/Delta. Liquefaction of that entire region is possible - not something I like to think about!

dave333 5y ago

Maybe they should build some large reinforced concrete buildings that can act as tsunami shelters and also fulfil a secondary function such as public library (do they still have those) or offices/shops or whatever. Maybe 100 ft high would be enough, but design it so that people can survive inside it even if it is temporarily overrun by the tsunami. Or you could build a larger number of small reinforced shelters that would be designed to be overrun but would keep people alive until the tsunami retreats.

irrational 5y ago
They don't need this along Cascadia. All of the major population centers are 60 miles inland (in between the coastal and cascade mountain ranges). There are just very small town on the coasts and the coastal mountain range rises very quickly from the coast. You can get to high ground from just about anywhere on the coast fairly quickly.

arethuza 5y ago

There is a fantastic set of videos on the geology of the Pacific Northwest by Nick Zentner available on Youtube: https://www.youtube.com/playlist?list=PLpwTojTevrmOfXmPVpGSa3UcKC_Lg5oVM https://www.youtube.com/playlist?list=PLpwTojTevrmOfXmPVpGSa... Edit: I'm nowhere near the area (I'm in Scotland) but I find the series absolutely fascinating.

jmcqk6 5y ago
Zentner's videos are forking fantastic. There is some really mind blowing stuff about the PNW geology. For example, Did you know there's a connection between Yellowstone, Smith Rock in Oregon, and Liberty Gold in central Washington? The possible connections between columbia river basalt and yellowstone is also very interesting. It's just a fantastic place to be for geology.