Question from an amateur: The earth's plates seem pretty large compared to the planet. This example has about 20 to 30 with about 6 seemingly making up the majority of the earth's surface. Is there a reason why they are so large? I'm writing a novel in which a planet, instead of having 20 to 30 plates, may have 100 small ones. That way, I don't have a handful of large oceans or large continents but a huge number of smaller Greenland to Hawaii sized island chains with dozens of large Mediterranean-sized seas. Is there some aspect of planetary tectonics that would explain why there would be more numerous but smaller plates? Thanks.