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[–] 83 points 6 months ago (16 children)

measured from satellites.

Overall that means a yearly subsidence rate of about 9.5 inches (24 centimeters). Over the course of less than a century, the drop has been more than 39 feet (12 meters), according to Cabral.

Holy shit.

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  • [–] 34 points 6 months ago (6 children)

    I guess the "lucky" part is that it's sinking evenly. Otherwise buildings would be collapsing all the time.

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  • [–] 6 points 6 months ago (5 children)

    IDK that seems scarier to me. If the whole thing is sinking evenly, what happens if/when whatever is holding it up gives way completely? Is the whole city going to fall into a sinkhole? Will there be stories of the lost city of Mexico City in a few thousand years?

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  • [–] 13 points 6 months ago (3 children)

    There's an aquifer under the city that supplies the city's water which they're pumping dry.

    The relentless pumping of groundwater and extensive urban development have severely depleted the underlying aquifer.

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  • [–] 6 points 6 months ago (2 children)

    Yeah that’s what made me think, “what happens when there’s a giant cavity under the city and the water is gone?”

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  • [–] 5 points 6 months ago* (last edited 6 months ago)

    All of the clay gets compressed which means the water can't drain into the ground anymore and the underground drainage canals get damaged. And then the city turns back into a fucking lake after it goes between drought and flooding because the only way to create a surface water reservoir is to turn the now sunken city back into a goddamn toxic and polluted lake/marsh. That or attempt to geoengineer it into a desert which also defeats the purpose of human habitation. Eventually "fixing" the problems will become more expensive than what they're worth for more development but nobody really knows where that inflection point lies for the valley of Mexico.

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  • [–] 5 points 6 months ago* (3 children)

    Consistently multiple inches a year is actually insane

    One must pose the question, then:

    ...Where is it going?

    Edit: thinks about tectonic plates ... Oh no...

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  • [–] 0 points 6 months ago (4 children)

    "Spotted" is still also accurate. How do you think a satellite could measure anything, except by looking at it?

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  • [–] 6 points 6 months ago (3 children)

    Because it's click bait sensationalism.

    Emphasis mine;

    The NASA estimates are based on measurements taken between October 2025 and January 2026 by a powerful satellite known as NISAR, which can track real-time changes on the Earth’s surface and is a joint initiative between NASA and the Indian Space Research Organization.

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  • [–] 2 points 6 months ago (2 children)

    NISAR

    https://en.wikipedia.org/wiki/NISAR_(satellite) :

    The NASA-ISRO Synthetic Aperture Radar (NISAR) mission is a joint project between NASA and ISRO to co-develop and launch an Earth observation satellite (EOS) equipped with dual-frequency synthetic aperture radar (SAR) in 2025. It will be the first radar imaging [emphasis added] satellite to use dual frequencies.

    https://en.wikipedia.org/wiki/Imaging_radar :

    Imaging radar is an application of radar which is used to create two-dimensional images, typically of landscapes. Imaging radar provides its light to illuminate an area on the ground and take a picture at radio wavelengths.

    It is, in a literal sense, "spotting" the subsidence using visual techniques, albeit at a lower EM frequency than what humans can see.

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