Enlarge / Harvey as seen from the International Space Station. (credit: NASA)
Strong and sturdy as bedrock may seem, it’s possible to pile enough weight onto the Earth’s surface to squish it downward a bit.

The planet’s great ice sheets, for example, have done this on a pretty significant scale. Many regions that are now relieved of the ice sheets they hosted during the last ice age are, in fact, still slowly rebounding upward today.

The coverage of modern, sensitive GPS networks allows us to see subtler versions of this process playing out even over the annual cycle of wet and dry seasons.

And, it turns out, these networks may have caught Hurricane Harvey’s record-setting rainfall depressing Earth’s crust just a little.
On Monday, Jet Propulsion Laboratory researcher Chris Milliner posted a plot of the change in GPS station elevation immediately after Harvey.

The data showed that the Houston landscape had sunk as much as two centimeters. While that’s not enough to worsen flooding that was measured in (many) feet, it’s actually quite impressive for a sudden change from a single weather event.

That’s a testament to the weight of the preposterous amount of water the area was under.
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