Why do earthquake happen at plate boundaries?
Earthquakes can occur anywhere, but usually occur along tectonic plate boundaries which are by definition faults in the Earth’s lithosphere. Plates are independently moving slabs of hard rock that pull apart from each other (divergent fault), grind past each other (transform fault), and push into each other (convergent fault). All three types of plate boundaries can produce earthquakes as the lithospheric plates either fracture from stress or the stress from grinding or collision is released when rock from either side of the fault snaps into a new position.
