TOWARDS A NOVEL ROBUST SLIP INVERSION FRAMEWORK ON NON-PLANAR 3D FAULTS: APPLICATION TO THE ILLAPEL 2015 EARTHQUAKE
As part of the ongoing FONDECYT-ANID (Chile) 1231684 QUEST project (Quantification of Uncertainty and ESTimation of fault slip using non-planar faults and the EPIC), we are developing a novel inversion framework for the kinematic characterization of earthquake rupture on realistic, non-planar three-dimensional fault geometries. The methodology employs a triangulated fault mesh and a continuous space-time slip representation using tent basis functions, allowing for improved resolution of complex rupture patterns.
A central innovation is the integration of the EPIC (Equal Posterior Information Condition) regularization scheme, which applies spatially and temporally adaptive smoothing based on the sensitivity of the data. This approach reduces inversion artifacts, enhances model stability, and improves the physical interpretability of the inferred rupture process. In parallel, we have developed MUSE (Multiscale Slip Estimation), an alternative approach that captures the spatial variability of data sensitivity by adaptively selecting the local scale of representation from a dictionary of basis functions. Additionally, epistemic uncertainties related to fault geometry and elastic structure are explicitly incorporated into the forward modeling framework.
We apply the methodology to synthetic and observed datasets. Current efforts focus on applying this framework to the 2015 Mw 8.4 Illapel earthquake, aiming to produce a physically consistent and uncertainty-aware rupture model of this key megathrust event in central Chile.