Analysis of ground deformation of viscoelastic half-space

In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movement. Large faults within the Earth's crust result from the action of plate tectonic forces, with the largest forming the boundaries between the plates, such as subduction zones or transform faults. According to elastic rebound theory, the tectonic earthquakes are caused by sudden release of elastic strain energy stored in the strain rock mosses in some regions of the earth in the lithosphere by fracture or fault movement produced by sudden relative displacement of neighbouring portions of the earth's crust. This relative movement occurs when the accumulated stresses become sufficiently large to overcome the local cohesive strength of the rock and /or the frictional forces which keep the faults in the locked state. A fault movement usually leads to a partial or full release of the accumulated stress. Repeated fault movements occur in the case of some active seismic faults separated by aseismic intervals of various durations.