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Hi, Mexico.
How are you feeling after that significant shake? Looks like the Cocos plate dove a bit deeper under the North American plate today, continuing its 60 mm/yr journey into the depths. https://twitter.com/usgsbigquakes/status/1275455693902893057">https://twitter.com/usgsbigqu...
How are you feeling after that significant shake? Looks like the Cocos plate dove a bit deeper under the North American plate today, continuing its 60 mm/yr journey into the depths. https://twitter.com/usgsbigquakes/status/1275455693902893057">https://twitter.com/usgsbigqu...
Lots & lots of video I can’t verify but are neat for demonstrating concepts.
Beware I’m not going to be able to pluck the original posters nor establish beyond plausibility that they’re from today while we dive into the science.
Beware I’m not going to be able to pluck the original posters nor establish beyond plausibility that they’re from today while we dive into the science.
Guitar strings vibrate at particular frequency based on length & thickness.
So do buildings.
Tightly-packed mixed-height buildings can be dangerous during quakes as they all sway slightly differently & can actually smash into each other: https://twitter.com/oncenoticiastv/status/1275471821278601216">https://twitter.com/oncenotic...
So do buildings.
Tightly-packed mixed-height buildings can be dangerous during quakes as they all sway slightly differently & can actually smash into each other: https://twitter.com/oncenoticiastv/status/1275471821278601216">https://twitter.com/oncenotic...
Every water body has a resonance frequency where it produces waves that align perfectly to constructively interfere with themselves, building bigger & bigger.
Seismic waves often align up with swimming pool resonance.
Store display hot tub (?) seiche: https://twitter.com/jinxywera/status/1275464173938339841">https://twitter.com/jinxywera...
Seismic waves often align up with swimming pool resonance.
Store display hot tub (?) seiche: https://twitter.com/jinxywera/status/1275464173938339841">https://twitter.com/jinxywera...
You can watch the channel seiche slowly build in this clip, each rebounding wave adding to the next.
Note:
the pups are fine, but please don’t go frolicking in seiche. In more wild conditions (like a tsunami resonating within a bay) they hide vicious currents. https://twitter.com/roger13as/status/1275460403061878786">https://twitter.com/roger13as...
Note:
the pups are fine, but please don’t go frolicking in seiche. In more wild conditions (like a tsunami resonating within a bay) they hide vicious currents. https://twitter.com/roger13as/status/1275460403061878786">https://twitter.com/roger13as...
Seismic codes are being constantly revised and updated as structural engineers learn more about how to absorb energy without breaking.
A common tactic is to build in flexibility and gaps.
Which can be a tad bit unnerving: https://twitter.com/aztecanoticias/status/1275477676577288193">https://twitter.com/aztecanot...
A common tactic is to build in flexibility and gaps.
Which can be a tad bit unnerving: https://twitter.com/aztecanoticias/status/1275477676577288193">https://twitter.com/aztecanot...
Sidewalks and roads can also break without built-in flexibility. So... gaps!
Note:
During an earthquake, please drop! (or lock! mobility devices) cover! & hold on! Walking on literally unstable ground is not a great idea. https://twitter.com/borderlineason/status/1275458572046856192">https://twitter.com/borderlin...
Note:
During an earthquake, please drop! (or lock! mobility devices) cover! & hold on! Walking on literally unstable ground is not a great idea. https://twitter.com/borderlineason/status/1275458572046856192">https://twitter.com/borderlin...
I’m seeing very few building damage vides (yay!), so I’m hesitant that this is from today. Even if it’s not, it’s a REALLY GOOD example.
Entering/exiting buildings is dangerous because that’s where shit is falling. Eek!
Stay inside OR outside until shaking stops. No fleeing! https://twitter.com/elpunto_mex/status/1275480497817137152">https://twitter.com/elpunto_m...
Entering/exiting buildings is dangerous because that’s where shit is falling. Eek!
Stay inside OR outside until shaking stops. No fleeing! https://twitter.com/elpunto_mex/status/1275480497817137152">https://twitter.com/elpunto_m...
Ideally, in a good building, your primary worry isn’t the building, but things inside the building.
Kitchens are by far my least-preferred place to be at home during quakes. Note the plate shards: https://twitter.com/ibero909fm/status/1275479861352493056">https://twitter.com/ibero909f...
Kitchens are by far my least-preferred place to be at home during quakes. Note the plate shards: https://twitter.com/ibero909fm/status/1275479861352493056">https://twitter.com/ibero909f...
Buildings of different heights swaying at different frequencies, but up close & personal: https://twitter.com/bon_miller/status/1275480792915828736">https://twitter.com/bon_mille...
Structural engineering for earthquakes isn’t just about absorbing energy. That flexibility needs to be balanced against enough rigidity for buildings to hold their shape.
...as rather terrifyingly demonstrated by this untied rebar that doesn’t yet have cross-bracing. (Ahhhhh!) https://twitter.com/bersa76/status/1275489246275670017">https://twitter.com/bersa76/s...
...as rather terrifyingly demonstrated by this untied rebar that doesn’t yet have cross-bracing. (Ahhhhh!) https://twitter.com/bersa76/status/1275489246275670017">https://twitter.com/bersa76/s...
Oh, wow. This lamp fixture is kinda perfect as a seismics demo.
Notice all the identical mini-pendants swing at the same frequency, but the rigid shell stats steady? https://twitter.com/gothaminformer5/status/1275454014675488769">https://twitter.com/gothaminf...
Notice all the identical mini-pendants swing at the same frequency, but the rigid shell stats steady? https://twitter.com/gothaminformer5/status/1275454014675488769">https://twitter.com/gothaminf...
Perfect angle on this swimming pool seiche!
It’s a single standing wave across. The crest & trough align so that it’s like the water is bouncing up and down.
ProTip: bathtubs resonate at a tens of seconds if you swish back& forth. https://twitter.com/caromeug/status/1275458890868506624">https://twitter.com/caromeug/...
It’s a single standing wave across. The crest & trough align so that it’s like the water is bouncing up and down.
ProTip: bathtubs resonate at a tens of seconds if you swish back& forth. https://twitter.com/caromeug/status/1275458890868506624">https://twitter.com/caromeug/...
Because swimming pool seiche are all about seismic waves matching the resonance frequency of the pool, they amplify to the point where you can still get them so far from the epicentre that you barely even notice ground shaking.
Like this: https://twitter.com/hayes_ernest/status/1275465398045949953">https://twitter.com/hayes_ern...
Like this: https://twitter.com/hayes_ernest/status/1275465398045949953">https://twitter.com/hayes_ern...
When waves propagate, the individual particules within the medium barely move. Energy propagates, matter not so much.
For example, while the wave splashes out, the bananas only bob back & forth in this unexpected fluid dynamics demo: https://twitter.com/desdepeninsula/status/1275489952898441216">https://twitter.com/desdepeni...
For example, while the wave splashes out, the bananas only bob back & forth in this unexpected fluid dynamics demo: https://twitter.com/desdepeninsula/status/1275489952898441216">https://twitter.com/desdepeni...
Look, I really, really love swimming pool seiche. I find their regularity weirdly soothing.
Slosh, slosh, slosh... https://twitter.com/scgbts/status/1275461610568441856">https://twitter.com/scgbts/st...
Slosh, slosh, slosh... https://twitter.com/scgbts/status/1275461610568441856">https://twitter.com/scgbts/st...
Seiche can happen with any multiple of the seismic frequency. Instead of one standing wave, this pool has a whole series of them.
...sigh. The dramatic length vs width dimensional difference on this pool make me wish I know its orientation vs seismic wave propagation direction. https://twitter.com/carloszup/status/1275494162373238786">https://twitter.com/carloszup...
...sigh. The dramatic length vs width dimensional difference on this pool make me wish I know its orientation vs seismic wave propagation direction. https://twitter.com/carloszup/status/1275494162373238786">https://twitter.com/carloszup...
The pool covers & lane dividers are another neat demo on how material properties impact structural behaviour during oscillation.
A tarp is a solid yet flexible object. It stays the same dimensions, but moves with the disruption without breaking. https://twitter.com/ponchole/status/1275463127597854720">https://twitter.com/ponchole/...
A tarp is a solid yet flexible object. It stays the same dimensions, but moves with the disruption without breaking. https://twitter.com/ponchole/status/1275463127597854720">https://twitter.com/ponchole/...
Seiche are significantly less soothing in industrial settings. https://twitter.com/theking12k/status/1275494549855625223">https://twitter.com/theking12...
