C H A P TER 99 both sudden and gradual

both sudden and gradual changes to Earth’s crust. Moving plates interact at divergent, convergent, and transform fault boundaries. Earthquakes are caused by the sudden movement of plates at plate boundaries. Volcanoes can erupt at plate boundaries or at hot spots. KEY IDEAS • C H A P T E R 99 • As you have learned, Earth’s surface is ... ................
................