How much have continents moved since the dawn of civilization 12,000 years ago?

Well, thats actually a much more complex motion. In the end, you don't just have mid-ocean ridges, you also have subduction zone. As you can imagine, if you are creating a lot of new surface area in one place (the seafloor) you have to be removing surface area in another (subduction zones). So, the East Pacific Rise is creating new material at 10 cm/year on either side. That means it is pushing North America east at 10 cm/year. BUT the Japan trench is actually swallowing the pacific at 8 cm/year, meaning to the west of the EPR, Asia only moves away at 2 cm/yr. So no, it doesn't take into account the full complexity. Throw in to the mix you need to calculate all this on the surface of a sphere and it gets worse.

We actually use a software called GPlates to model this. We can input things like modern plate boundaries, spreading rates, convergence rates, and have it tell us the bigger picture. When you see reconstructions of Pangaea and Gondwanaland, chances are it was made with this software.

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