Broadband dynamic rupture modeling with fractal fault roughness,
frictional heterogeneity, viscoelasticity and topography: the 2016 Mw
6.2 Amatrice, Italy earthquake
Abstract
Advances in physics-based earthquake simulations, utilizing
high-performance computing, have been exploited to better understand the
generation and characteristics of the high-frequency seismic wavefield.
However, direct comparison to ground motion observations of a specific
earthquake is challenging. We here propose a new approach to simulate
data-fused broadband ground motion synthetics using 3D dynamic rupture
modeling of the 2016 Mw6.2 Amatrice, Italy earthquake. We augment a
smooth, best-fitting model from Bayesian dynamic rupture source
inversion of strong-motion data (<1 Hz) with fractal fault
roughness, frictional heterogeneities, viscoelastic attenuation, and
topography. The required consistency at long periods allows us to
quantify the role of dynamic source heterogeneities, such as the 3D
roughness drag, from observational broadband seismic waveforms. We
demonstrate that 3D data-constrained fully dynamic rupture synthetics
show good agreement with various observed ground-motion metrics up to
~5 Hz and are an important avenue towards non-ergodic,
physics-based seismic hazard assessment.