The Golden Gate Bridge
Apr. 26th, 2023 05:42 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
ysabetwordsmith... is preparing for the Big One.
The seismic modifications look promising. I estimate they will be very helpful against "typical" earthquakes of 6-7 magnitude. They might withstand up to level 8. I sincerely doubt that they will stand up to level 9 let alone more than that. (Remember, this is a logarithmic scale and each level is ten times worse than the previous one.)
The Ring of Fire is a bucking hellhorse. The West Coast is primed for a full rip. That doesn't mean it will happen that way, but it's quite likely. Several major faults have been locked long enough that they are overdue for a massive quake. One of those is the Cascadian Subduction Zone, the key to the "Really Big One," because when it rips it tends to cause catastrophic damage. Another is the San Andreas. Because the faults are connected, it's possible for an earthquake to travel in chain reaction from one to another, something I've only seen mentioned in the last few years but is pretty obvious if you look at a fault map or have ever played a game of Jenga.
Bluntly put, extant technology cannot stand up against a magnitude 9 earthquake, and very little will withstand even an 8. The one thing we have that really stands a chance is a monolithic dome, and that's less about human engineering than it is about geometry and physics. That'll stand up to a lot of bucking and shaking, but not even a dome will survive if the ground shears right underneath it -- or liquifies, or gets buried under a landslide, all things likely to happen in higher-level earthquakes.
By all means, prepare for earthquakes. Update your infrastructure as best you can. But understand the limits of technology against the power of a planet that's about to let out its belt a notch. The best thing you can do is get the hell out of the way.
Extensive information about the Ring of Fire, the West Coast, and its earthquake / tsunami risks is available in the notes for poems in my thread on the Big One.
The seismic modifications look promising. I estimate they will be very helpful against "typical" earthquakes of 6-7 magnitude. They might withstand up to level 8. I sincerely doubt that they will stand up to level 9 let alone more than that. (Remember, this is a logarithmic scale and each level is ten times worse than the previous one.)
The Ring of Fire is a bucking hellhorse. The West Coast is primed for a full rip. That doesn't mean it will happen that way, but it's quite likely. Several major faults have been locked long enough that they are overdue for a massive quake. One of those is the Cascadian Subduction Zone, the key to the "Really Big One," because when it rips it tends to cause catastrophic damage. Another is the San Andreas. Because the faults are connected, it's possible for an earthquake to travel in chain reaction from one to another, something I've only seen mentioned in the last few years but is pretty obvious if you look at a fault map or have ever played a game of Jenga.
Bluntly put, extant technology cannot stand up against a magnitude 9 earthquake, and very little will withstand even an 8. The one thing we have that really stands a chance is a monolithic dome, and that's less about human engineering than it is about geometry and physics. That'll stand up to a lot of bucking and shaking, but not even a dome will survive if the ground shears right underneath it -- or liquifies, or gets buried under a landslide, all things likely to happen in higher-level earthquakes.
By all means, prepare for earthquakes. Update your infrastructure as best you can. But understand the limits of technology against the power of a planet that's about to let out its belt a notch. The best thing you can do is get the hell out of the way.
Extensive information about the Ring of Fire, the West Coast, and its earthquake / tsunami risks is available in the notes for poems in my thread on the Big One.
(no subject)
Date: 2023-04-26 11:41 pm (UTC)That first link is malformed and goes nowhere.
Fixed!
Date: 2023-04-27 12:47 am (UTC)Re: Fixed!
Date: 2023-04-27 01:51 am (UTC)That works... interesting tech they're retrofitting with, which should be good upto 7.8, but as you say, there's nothing that will protect against a magnitude 9 or higher.
Re: Fixed!
Date: 2023-04-27 02:43 am (UTC)It'd be better if modifications came with, and were advertised with, an estimation of how much force they could withstand without damage, with minor damage, with repairable damage, and their catastrophic failure level.
I also think it'd be cool to have contests among engineers, architects, etc. to design quake-resistant structures and test them on shake tables to see what works best. Presently, the testing is erratic at best because there aren't many shake tables available. It'd be better if all building designs for earthquake-prone areas got tested before deployment -- and if the best ones got a prize including cash and promotion.
Re: Fixed!
Date: 2023-04-27 03:23 am (UTC)A lot of people might assume that the honest assessment is an inferior product compared to the less honest use of the term "earthquake-proof."
>>I also think it'd be cool to have contests among engineers, architects, etc. to design quake-resistant structures and test them on shake tables to see what works best.<<
1) Do it as a kid's contest...or at least start it out that way.
2) Keep in mind that the square-cube law means that the same design will have different durability depending on their size. This applies as much to architecture as to bugs and humanoid robots...
Re: Fixed!
Date: 2023-04-27 03:47 am (UTC)Yes, but if they trust things farther than the limits, that is worse.
"Earthquake-resistant" is a better term. "Seismic safety features" is another option.
>> Do it as a kid's contest...or at least start it out that way.<<
Good idea.
>> Keep in mind that the square-cube law means that the same design will have different durability depending on their size. This applies as much to architecture as to bugs and humanoid robots... <<
People who run shake tables have math and software designed to analyze results and scale them. Only a small building, or a sample part, will fit on a shake table so they have to extrapolate most of the time.
Re: Fixed!
Date: 2023-04-27 03:43 pm (UTC)I was kind of figuring that a lot of people would go for the thing marketed as "earthquake-proof" (thereby expecting more than it can reasonably provide), but turn their noses up at the more honestly-rated "rated for up to X-magnitude" items.
A lot of people are so used to being sold sizzling unicorn steak, that they might still prefer it over a nice cut of regular old beef.
>>"Earthquake-resistant" is a better term. "Seismic safety features" is another option.<<
I approve of these terms.
Re: Fixed!
Date: 2023-04-27 03:44 pm (UTC)(no subject)
Date: 2023-04-27 03:41 pm (UTC)Thoughts
Date: 2023-04-27 06:25 pm (UTC)Yikes.
I'm also unhappy with the antics that Yellowstone is throwing periodically. Changes in the behavior of geysers, fumaroles, etc. hint at changes in the rock stack and/or magma underneath.
And of course, a major earthquake in one place can set off reciprocal ones elsewhere to even out the stress until stability is achieved.
>> And we don't typically build for earthquakes here.<<
You might want to take some precautions.
Also, Washington and Oregon paid no attention to earthquake or tsunami safety until quite recently, so when Cascadia rips, a huge amount of infrastructure will fail. There is neither money nor time to fix it all before then, even if people weren't dragging their feet like they are. I feel sorry for seismologists in that area.
Re: Thoughts
Date: 2023-04-27 08:36 pm (UTC)I remember, though, when Mt St Helens went. We got ash fall all the way over in Michigan. So yeah, if Yellowstone goes, it'd likely set off St Helens, Hood, et al too, all the way down.
Re: Thoughts
Date: 2023-04-27 09:42 pm (UTC)That river never did like two-legs and is actively pissed with them now. It's going to jump its bed -- in some places that's long overdue from human tampering -- so a big shakeup would likely trigger that. Also it's the most likely rip line at present if Yellowstone goes off.
>>I remember, though, when Mt St Helens went. We got ash fall all the way over in Michigan. So yeah, if Yellowstone goes, it'd likely set off St Helens, Hood, et al too, all the way down.<<
Yeah, we got ash in Illinois too.
Look at a map and you can see that the Rockies in the west and Appalachians in the east anchor the edges of the continent. But the middle is much lower. It has a tendency to rip out and be water. Here is a previous example. While it's unlikely to be that extreme this time, if the edges jump up and the middle drops, there going to be some degree of "lots more water there than now."