Near-Source Ground Motions and Their Variability Derived from Dynamic Rupture Simulations Constrained by NGA-West2 GMPEs

ABSTRACT Empirical ground-motion prediction equations (GMPEs) lack a sufficient number of measurements at near-source distances. Seismologists strive to supplement the missing data by physics-based strong modeling. Here, we build database ~3000 dynamic rupture scenarios, assuming vertical strike-slip fault 36 × 20 km embedded in 1D layered elastic medium and linear slip-weakening friction with heterogeneous parameters along fault. The is built Monte Carlo procedure follow median variability Next Generation Attenuation-West2 Project GMPEs Boore et al. (2014) Joyner–Boore distances 10–80 km. synthetic events span magnitude range 5.8–6.8 have static stress drops between 5 40 MPa. These are used simulate ground motions stations within from saturate distances, their increases near compared distant ones. In database, within-event between-event extracted for employing mixed-effect model. lower than its empirical value, only weakly dependent on period, generally larger 1/4 value periods >1 s. We show that this can be reconciled considering epistemic error Mw when determining GMPEs, which not present data.