Study on the surface deformation law of buried faults based on the Okada model

Based on the elastic half-space dislocation theory (Okada model), this paper systematically investigated the characteristics and law of surface deformation fields induced by the dislocation of buried normal faults. By constructing a numerical model and systematically changing the geometric parameters of fault, the study mainly performed a quantitative analysis on the critical controlling effects of fault burial depth and dip angle on the distribution range, width, and spatial location of surface rupture zones. The study shows that the width of surface rupture zone varies nonlinearly (first increasing significantly and then flattening out) as the fault burial depth increases, indicating that beyond a critical depth, the control effect of burial depth on the amplitude of surface deformation weakens. Additionally, the rupture zones generated by lowdip-angle normal faults show a distinct displacement trend towards the foot wall, and their overall width is significantly reduced compared to high-dip-angle faults. These quantitative insights provide important theoretical foundations for accurately assessing the potential surface rupture hazards of buried faults, scientifically determining reasonable setback distances for major urban cross-fault engineering structures, and planning seismic fortification for lifeline engineering.