A Method to Generate Initial Fault Stresses for Physics-Based Ground-Motion Prediction Consistent with Regional Seismicity

ABSTRACT Near-field ground motion is the major blind spot of seismic hazard studies, mainly because challenges in accounting for source effects. Initial stress heterogeneity an important component physics-based approaches to ground-motion prediction that represents effects through dynamic earthquake rupture modeling. We hypothesize on a fault primarily originates from past background seismicity. develop new method generate stochastic distributions as superposition residual stresses left by previous ruptures are consistent with regional size and hypocentral depth. validate our Mw 7 models suitable California obtaining satisfactory agreement empirical scaling laws equations. To avoid excessive radiation produced abrupt arrest at preset borders, we achieve spontaneous incorporating growth fracture energy function distance. Our analyses reveal particular signatures initial heterogeneity: can locally propagate supershear speed near highly stressed areas; position high-stress low-stress areas due determines how peak amplitudes polarization spatially vary along fault, slow down decrease drop. also find medium stratification zone amplifies slip consequent motion, which requires understanding interaction between site dynamics. approach advances relations features statistics seismicity, capability integrate information about seismicity into near-field prediction.