Abstract：Earthquake fault dislocation-induced ruptures of soil layers are simulated by finite element method. The study demonstrates soil rupture propagation and characteristics，and also proves the observed earthquake phenomenon that a ground surface rupture failure does not mean a penetrating rupture failure. The simulation results indicate that the soil rupture starts at interface between soil and bedrock and expands upward. Furthermore，one or two ruptures appear at ground surface and extend downward with the increase of fault dislocation，and the ruptures from bedrock and ground surface meet somewhere in soils so that a penetrating rupture from bedrock to ground surface occurs if fault dislocation is large enough. Three kinds of soil ruptures including buried rupture，non-penetrating ground surface rupture and penetrating soil rupture are presented in case of different fault dislocations and soil conditions. The obvious effects of soil thickness and properties on characteristics of soil rupture are revealed. The ground surface rupture belt is enlarged due to the increase of soil thickness if a ground surface rupture occurs，and the rupture angle is almost not affected by soil thickness and properties. The width of rupture belt of sands is smaller than that of clays，and the penetrating rupture occurs more easily for harder soil than for softer soils. In condition of reverse fault，the value of bedrock fault dislocation for initial ground surface rupture occurring is 80% or less than that for a penetrating rupture occurring，and the vertical value of bedrock fault dislocation for a penetrating rupture occurring is 5%less than that of soil thickness for soil layer with thickness less than 50 m.
