Earth's lithosphere is broken into ~15 major plates riding on the slowly flowing mantle
(a few cm/yr — fingernail speed).GPS confirms the motions. Three boundary types do almost all the work:
divergent (plates apart — new crust, shallow quakes, ridges & rifts), convergent (one plate sinks
or two crumple — trenches, volcanic arcs, the deepest earthquakes, the tallest mountains), and
transform (plates sliding past — shallow, violent strike-slip quakes like San Francisco 1906).
The magnetic stripes in the divergent view are real: as lava cools through the Curie point it
freezes the Earth's magnetic field direction — flipped many times in history — giving stripe pairs that proved
seafloor spreading in the 1960s. Ring of Fire = subduction zones around the Pacific.