Numerical modeling of ground deformation and source mechanism related to co-seismic change in gravitational potential

Abstract

Abstract The release of gravitational potential energy is implicit in ground surface deformation, as was seen in the 1954 Fairview Peak, 1964 Alaska and 1976 Tangshan earthquakes where more energy was released by surface subsidence than was radiated as seismic waves. Based on the numerical results of dip and thrust faulting driven by either gravitational tectonic stress alone or additional external forces, the elastic stress accumulation process in the front of the fault tip is required, as is usual, prior to any faulting slip, but the energy release would be mainly derived from the downward movement of the hanging wall of a normal fault or the footwall of a thrust fault. In other words, there will be a decrease in gravitational potential energy in the upper part of the subsiding wall to generate seismic waves, and an increase in elastic strain energy in the lower part either to cause after shocks or to bring about cessation of further fault movement. In addition, by geodetic surveying along a fault prior to an earthquake opportunities exist to judge the nature of the tectonic force and the damage zonation.