Hurricane Harvey's Flood Was So Extreme, It Pushed The Earth's Crust Down By 2cm
Hurricane Harvey has taken an enormous toll on the people and infrastructure of Houston, Southeast Texas and Louisiana, but one thing that's harder to see is the impact the storm left on the Earth itself.
But for geologists, Harvey presents a fascinating case of the surface of the Earth rapidly changing shape. Chris Milliner, an earthquake scientist for NASA's Jet Propulsion Laboratory, posted this alarming stat on Twitter:
Milliner took to the replies of his tweet to answer questions from followers and skeptics. Here are some facts:
- While it's possible some of the subsidence observed around Houston is due to soil compacting, some of the measurements were taken from stations resting on bedrock, which means the Earth's crust did indeed flex.
- It's possible the Earth's crust around Houston could eventually uplift back to its original position over time, but that's not a guarantee.
- This phenomenon isn't technically caused by heavy rainfall, but rather the extreme floods that followed the rainfall. As Milliner wrote on Twitter, sitting water is heavy; 1 cubic meter weighs 1 metric ton, or 2204.62 pounds.
And a lot of metric tons fell, which this helpful Washington Post visualization helps put into perspective:
And Harvey isn't the only storm to show up on geologists' radars. Here's a frightening chart of forthcoming Category 5 Hurricane Irma and its effect on seismometers — devices usually used to measure earthquakes: