Module 3 of 5 · Text
Where do volcanoes and earthquakes occur?
The crust is broken into plates
-The lithosphere (crust and upper mantle) is broken into 14 major plates and 32 much smaller plates
-Where these plates meet are known as plate margins
Convection currents in the mantle cause the plates to move
Hot mantle is thought to rise, cool and sink again in a circular motion
But some scientists have other theories
-Slab-pull - the weight of the denser plate sinking into the mantle at ocean trenches. This pulls the rest of the plate along
-ridge-pull - as oceanic ridges build up the weight of the ridge pushes the plates apart
-The lithosphere (crust and upper mantle) is broken into 14 major plates and 32 much smaller plates
-Where these plates meet are known as plate margins
Convection currents in the mantle cause the plates to move
Hot mantle is thought to rise, cool and sink again in a circular motion
But some scientists have other theories
-Slab-pull - the weight of the denser plate sinking into the mantle at ocean trenches. This pulls the rest of the plate along
-ridge-pull - as oceanic ridges build up the weight of the ridge pushes the plates apart