Imagine that you are looking at pictures sent back of a newly discovered planet. You are specifically looking for evidence of plate tectonics. What topographic features would you look for and why?
Topographic features revealing mountain ranges and deep valleys as well as volcanic activity would be indicators of plate tectonics, because these formations are consistent with plate existence.
Plate tectonics will invariably result in the formation of mountain ranges when the edges of the plates collide and one is pushed upward above the other. At the other end of the plate there may be a large void or valley that may be filled with water. Some of the plate may be dissolved back into the mantle of the planet in a process called subduction.
Volcanic activity is a indicator of plate tectonics, because the spaces between the plates provide molten rock (called magma) from the center of the planet a route to reach the planet's surface, along with its associated heat and gases.
The result could be hot springs or gysers where water is present, continuous magma flows, volcanic eruption, or the formation of a volcano.
These features will show up as topographic features in the pictures.
What will not show up are the earth quakes related to the motion of the plates and the volcanic activity.
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