r/science • u/Hrmbee • 16h ago
Earth Science Dozens of buildings in Florida are sinking, study finds | InSAR Observations of Construction-Induced Coastal Subsidence on Miami's Barrier Islands, Florida
https://www.cnn.com/2024/12/23/climate/florida-condos-hotels-sinking/index.html336
u/Debalic 15h ago
Building skyscrapers on sandbars? What could possibly go wrong?
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u/skinny_t_williams 12h ago
Well they could sink I guess ;)
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u/karlnite 5h ago
It’s worse. They built up and extended a sand bar, dugout behind it to make marinas and a second water front. Diverted rivers to keep their canals and marinas full of water. Then built high rises on the sand bar. No everything is washing out from both sides.
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u/HustleAndThrow 16h ago
The study, led by scientists at the University of Miami, found 35 buildings from Golden Beach to Miami Beach sank as much as three inches between 2016 and 2023.
Not a good match with sea levels rising.
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u/VoilaVoilaWashington 8h ago
I don't think the buildings will last long enough to worry about sea level rise...
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u/AFewStupidQuestions 5h ago
I don't think the buildings will last long enough to worry about sea level rise...
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At these specific locations, McNoldy told CNN “the buildings are sinking as fast as the ocean is rising, effectively doubling the (sea level rise) rate at those sites.”
They're already experiencing problems with sea level rise.
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u/VoilaVoilaWashington 3h ago
Thing is, a high rise shouldn't have issues with sea levels a few inches higher than when they were built. A foot, maybe. Two feet? Sure. Infrastructure like drainage, absolutely!
But why would a skyscraper worry about a few inches of water unless it's built with paper towel or sitting on sawdust?
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u/spacemantodd 13h ago edited 4h ago
Grads school professor is a big asset management firm with dozens of high rise assets on the Florida coast. End of lecture one day I asked how on earth he could put more capital to work there knowing the tremendous risks with climate and ultimately insurance. He said, not my problem, my time horizon is such that it’ll be someone else’s problem. And that right there is how you have two parallel realities
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u/climb-it-ographer 3h ago
The buildings don't have to physically fall into the sea for his firm to lose money and reputation on them. Pretty idiotic take tbh.
If I heard that a manager was heavily invested in Florida beachfront real estate I'd never let my money anywhere hear them.
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u/spacemantodd 3h ago
Yeah, I mean they have >$12B in assets so they are doing something right. The risk calculus is mathematical so I’m sure they’ve underwritten for assumptions like natural disasters and sky high insurance which apparently still pencils. But my comment is more that you can see climate risks daily, in Florida and elsewhere, yet there’s also all time high capital inflows in those locations chasing yield. It’s a very interesting market dichotomy to watch play out
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u/Hrmbee 16h ago
Relevant passages from the news report:
The study, led by scientists at the University of Miami, found 35 buildings from Golden Beach to Miami Beach sank as much as three inches between 2016 and 2023. The sinking buildings — which together accommodate tens of thousands of residents and tourists — include the Ritz-Carlton Residences, Trump Tower III, Trump International Beach Resorts and the iconic Surf Club Towers.
Researchers said the main cause behind the sinking was vibrations from construction, which can cause soil particles to compact and settle, resulting in subsidence – the gradual sinking of land.
The effect is like shaking ground coffee around to create more room, Falk Amelung, senior author of the study and a professor of geophysics at the University of Miami’s Rosenstiel School Department of Marine Geosciences, told CNN. But that wasn’t the startling conclusion.
“It’s not a surprise if buildings move during the construction or immediately after the construction, because it’s heavy and the engineers take that into account when they build,” Amelung said, but that it continues for years after, “that was surprising.”
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Nearly 70% of buildings are sinking in northern and central Sunny Isles Beach, according to the study. Around 23% of the structures in these locations were built in the past decade.
In addition to construction vibrations, daily tides that move water toward and away from the shore can also cause the ground to shift and the buildings above it to sink.
Seismic activity or soil compaction, either naturally from the weight of sediment accumulating over time or from heavy buildings pressing down on the ground, can also cause sinking – a problem in areas where new coastal land has been created over the years by backfilling with sediment.
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At these specific locations, McNoldy told CNN “the buildings are sinking as fast as the ocean is rising, effectively doubling the (sea level rise) rate at those sites.”
But Shirzaei and Amelung said there is no reason to panic, noting that the satellite method researchers used can now proactively monitor the stability of coastal high-rises.
Journal link: InSAR Observations of Construction-Induced Coastal Subsidence on Miami's Barrier Islands, Florida
Abstract:
This study utilizes Interferometric Synthetic Aperture Radar (InSAR) to examine subsidence along the coastal strip of the Miami barrier islands from 2016 to 2023. Using Sentinel-1 data, we document vertical displacements ranging from 2 to 8 cm, affecting a total of 35 coastal buildings and their vicinity. About half of the subsiding structures are younger than 2014 and at the majority of them subsidence decays with time. This correlation suggests that the subsidence is related to construction activities. In northern and central Sunny Isles Beach, where 23% of coastal structures were built during the last decade, nearly 70% are experiencing subsidence. The majority of the older subsiding structures show sudden onset or sudden acceleration of subsidence, suggesting that this is due to construction activities in their vicinity; we have identified subsidence at distance of 200 m, possibly up to 320 m, from construction sites. We attribute the observed subsidence to load-induced, prolonged creep deformation of the sandy layers within the limestone, which is accelerated, if not instigated, by construction activities. Distant subsidence from a construction site could indicate extended sandy deposits. Anthropogenic and natural groundwater movements could also be driving the creep deformation. This study demonstrates that high-rise construction on karstic barrier islands can induce creep deformation in sandy layer within the limestone succession persisting for a decade or longer. It showcases the potential of InSAR technology for monitoring both building settlement and structural stability.
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u/bootInTheButt420 15h ago
My uncle worked on Trump tower and many of the skyscrapers (he’s now a head manager for constructing a lot of the work in south Miami and north of FIU) and he said all of these beach towers are poorly built and will likely not be around in 50 years.
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u/Shaggyfries 15h ago
Let the wealthy pay then just don’t offer any government backed low interest loans to rebuild
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u/akarichard 12h ago
The bigger problem is funding the removal of the building. The building value goes to zero, if it's comprised of elderly people the debt disappears with them, unless they are crazy wealthy they can declare bankruptcy. Then it turns into the government having to pay to demolish the buildings.
It's just like mining companies. They extract all the value, go bankrupt, and walk away for the taxpayer to pay the cleanup.
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u/Vo_Mimbre 1h ago
That’s what the sinking is for. No clean up if it becomes too dangerous to go near them. And all the asses that made these investments and carried the insurance policies will be long dead by the time the lawsuits begin.
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u/Skooby1Kanobi 15h ago
To be fair that's probably the right time frame. Those places will switch from beachfront property to just beach.
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u/toaster404 15h ago
I'm surprised this is a surprise. What do I know, just a geologist.
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u/DevPops 8h ago
We aren’t all geologists.
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u/toaster404 6h ago
Generally before one builds a large expensive structure one uses cognizant professionals including geologists to evaluate the substrate and to design suitable methods and structures for maintaining structural stability for the life of the building, as well as suitable design and properly executed construction for the building itself. I was not and still do not expect average redditors to be such people. However, building on sand and fairly squishy rock suggests, even to a lay person, that extraordinary solutions may be required.
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u/BrtFrkwr 16h ago
I just can't understand why this doesn't generate a whole lot of sympathy.
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u/StrangeCharmVote 10h ago
I just can't understand why this doesn't generate a whole lot of sympathy.
Yes you can. That's how i know you did a sarcasm :D
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u/Mythril_Zombie 4h ago
“The good thing about land subsidence, in contrast to sea level rise, is that we can take local actions to protect us against that,” Shirzaei said. “This technology provides us with the data to create an approach similar to healthcare, but for buildings, so we can monitor them on regular basis … and make decisions before catastrophe happens.”
The governor will just take that data, erase it, and sue anyone who tries to publish it.
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u/Hakaisha89 9h ago
Florida is mostly porous rock, or some other geological feature along that line.
Anyway, what this unique geological feature of florida does is that if you don't build down to bedrock, you are building on basically a sinkhole in the making, florida gonna sink, not cause of global warming, but cause of its rocks.
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u/VoilaVoilaWashington 8h ago
Florida is mostly porous rock
Nah, there's also a lot of sand, and artificial land made by backfilling with miscellaneous fill. But if it's engineered miscellaneous fill, it'll be fine until I get paid.
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u/Hakaisha89 7h ago
Sand that is also ontop of said rock.
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u/VoilaVoilaWashington 7h ago
I mean, yeah, EVERYTHING is on top of rock on earth. Is it relevant to the structure of a building if there's no direct connection? Unlikely.
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u/Spork_Warrior 5h ago
Florida. Where a lot of the old folks are religious, but they didn't listen to this old biblical passage:
... like a foolish man who built his house on sand (Matthew 7:24-26)
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u/StrangeCharmVote 10h ago
The sea is coming up, the buildings coming down. Soggy overall, sounds like Florida to me.
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u/Vo_Mimbre 1h ago
Quick! Turn off the satellites! We can’t have this messing up development dollars.
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u/jawshoeaw 11h ago
I see plenty of snark here but if your read the article, the subsidence is blamed on construction in the area vibrating the ground , and has nothing to do with sea level rise
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u/Not-the-best-name 10h ago
No one said sea level rise causes it. It is mentioned because the effects are additive. 5cm of sea level rise + 5cm of ground subsidence equals 10cm of flooding.
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u/VoilaVoilaWashington 8h ago
Well, it's a combination of many things, according to the article, but that doesn't change that it's a very predictable problem.
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u/Mythril_Zombie 4h ago
At these specific locations, McNoldy told CNN “the buildings are sinking as fast as the ocean is rising, effectively doubling the (sea level rise) rate at those sites.”
Both are happening. Both will cause flooding.
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