A New Kinematic Rupture Generation Technique and Its Application

Summary We present a novel method for generating kinematic rupture models for near-source broadband ground motion simulations. Our approach constructs realistic rupture-parameter distributions for slip, rupture velocity and rise time using Von Karman (VK) fields. To more realistically model the slip pattern, we propose rescaling the VK field to follow a truncated exponential distribution rather than a Gaussian, following previous findings on inversion results. For rupture propagation, we initiate the rupture from slip-constrained hypocenter locations, which is crucial for accurately capturing directivity effects. Finally, to characterize the local slip-rate evolution at each computational point on the fault, we propose to employ the regularized Yoffe functions to which small-scale variations are added using 1D VK-fields whose properties are constrained from a database of dynamic rupture simulations. The statistical properties of these fields are calibrated using a database of dynamic rupture simulations, ensuring appropriate high frequency radiation from the generated rupture. Our rupture generator produces kinematic source descriptions to simulate ground motions that successfully reproduce the mean and standard deviation from ground motion models (GMM) for Mw 6.0-7.0 earthquakes. Additionally, our generator allows for the integration of low-frequency source inversions and complements the high frequency radiation of a seismic rupture with physics-constrained stochastic variations. Our broadband pseudo-dynamic kinematic rupture generator facilitates and possibly improves the simulation of realistic high-frequency ground motions to advance seismic hazard analysis.