Displacement Field of Dislocation in a Twophase Saturated Medium in Semi-Infinite Space

The elastic dislocation theory is an important tool to study sources of earthquakes. Using the dislocation theory of the single‐phase medium, the obtained ground deformation field is stable and constant. However, the observed ground deformation field after earthquakes is varied which may be associated with fluids in rocks. The purpose of this study is to acquire the displacement field in a two‐phase saturated medium in semi‐infinite space. Our method is utilizing the cylinder function expression of the Green function for a two‐phase saturated medium in semi‐infinite space under a concentrated force, via vector transformation of the Helmholtz equation, and then superimposing the effect field of a free surface. Combining the DD model of Nur and assumption on water in and water out, our result can explain the variations of the ground deformation field before and after earthquakes.