You know, there are a lot of theories involving holes at the poles, seismic activity, etc. etc. (in case of real theories)
Btw I literally have no idea about the tectonic motion. Why couldn't there be if the world is hollow? The center of gravity (and also what we could consider the center of the earth) is just at the middle of the "two worlds".

Posting some pics to give you an idea because whenever I said "hollow earth" people thought that when you fell in the holes at the poles you'd fall in the center of earth, lol

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