Earthquakes

[rov1200]

Why do the tectonic plates often lie along coastal strips? Take South America starting from Chile and up via San Francisco in the US.

[beso]

Seismically active costal locations are subduction zones. The oceanic plate is sliding under the edge of the lower density continental plate.

[rov1200]

Thanks for that info. I am now able to look up subduction zones to give me more information.

[jno]

one slides under the other and is therefore more likely to end up covered in water, I suppose. I'm not sure the planet itself cares whether certain areas are covered in water or not - if the planet was dry, the borders of the plates would be too. But since water exists on the earth's surface, it covers the lower plates ratehr than the higher ones.