Constraining Frictional Properties on Fault by Dynamic Rupture Simulations and Near‐Field Observations

Abstract

AbstractFrictional properties of seismogenic faults play critical roles in earthquake generation and rupture propagation. Although laboratory measurements have well revealed the frictional parameters of a variety of rock samples, those on seismogenic faults remain difficult to determine due to the strong trade‐off between critical slip‐weakening distance (d0) and strength drop. Here we conduct dynamic rupture simulations to determine the frictional parameters on the fault where the 2015 Mw7.8 Nepal earthquake occurred, with constraints from near‐field seismic and geodetic observations, and kinematic source models. By utilizing different trade‐off patterns of source parameters and multiple observations for the first time, we can determine the frictional parameters of the seismogenic fault. The best fit dynamic model yields a d0value of ~0.6 m, in contrast to the previous kinematical estimation of ~5 m (Galetzka et al., 2015, https://doi.org/10.1126/science.aac6383). The average fracture energy of this event is J/m2. Such approach can be used to determine the frictional parameters on seismogenic faults, which could serve for seismic hazard assessment by predicting ground motion from dynamic rupture simulations.