Marie Tharp mapped the ocean floor using echolocation data and found a massive rift running down the middle of the Mid-Atlantic Ridge, lining up with where the continents on either side would fit together. Princeton geologist Harry Hess later built a theoretical model around this finding, proposing seafloor spreading, where churning magma beneath the crust pushes plates apart and drives their motion. Together these findings established the theory of plate tectonics, which is now the basis for understanding earthquakes.
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The hosts date Tharp's discovery of the rift to 1952 and Hess's seafloor spreading model to 1962.
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A recent earthquake in Venezuela is mentioned as an example of a phenomenon plate tectonics theory helps explain.
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1:24:52We we're just it's unbelievable what we can do here. 1952 discovery of the Mid-Atlantic rift and plate tectonics. We've seen a recent major earthquake in Venezuela. Uh which again that this discovery helps to explain what's going on there. >> Exactly. I mean before this we didn't know about plate tectonics. We didn't know about plates. Okay. Then along comes um Marie Tarp. She discovers the massive rift in the mid-Atlantic ridge. She was she was using um she was using sort of data from echolocation of the ocean floor and she was like there's this like massive line right in
1:25:33the middle >> and it's like right in the middle and it like follows where the continents should meet you know if they were to meet like there's got to be something that's happening right and she created this theory of plate tectonics then a Princeton geologist Harry Hess in 1962 he created the theoretical model for it and he said There's seafloor spreading that's happening because the magma is churning up energy and that's create like the plates are on top of this fluid sort of ocean of magma and they're moving around and this is the establishment of plate tectonics. It's huge. I mean this is how we understand earthquakes now. You know >> if you turn a pizza upside down so the cheese is on the ground and you look at the crust and you move it around the
1:26:14crust will move cuz the cheese below is a little is a little squishy. >> Yeah. >> 19