As plates move, they bend and stretch the rocks of the . When the rocks reach their limit, they . As a result huge cracks in the crust called form at and below the . Different faults are produced by different kinds of plate . Normal faults are created along boundaries. Strike-slip faults are produced at boundaries, and convergent boundaries create faults. The broken faults scrape against each other, gradually moving. They can move slowly, a year, or suddenly. These sudden movements shake the and release large amounts of . This is the beginning of a(n) .