Tectonic Earthquakes Most earthquakes occur at plate margins due to tension, compression or shearing forces. Rocks at plate margins are in constant motion and are being pushed, pulled, bent, twisted and folded
Brittle deformation = the permanent change that occurs in a solid material due to the growth of fractures and/or sliding on fractures. A fracture is a surface of discontinuity (includes cracks, joints and faults). Faults result from shear stresses, and joints result from tensile stresses:
The change in volume or shape of an object that results from stress is called strain. The response of rocks to stress can be divided into - elastic response: rock returns to original shape - ductile or plastic response: permanent deformation without fracture; occurs above the so-called elastic limit
地球内部过程 Tsunamis海啸 and Coastal Flooding Coastal areas, especially around the Pacific Ocean basin where so many large earthquakes occur, may also be vulnerable易于to tsunamis