Bayesian inference of earthquake source parameters: kinematic and dynamic finite fault models

• Applicant: Dr. Alice-Agnes Gabriel
• Subject Area: Geophysics
• Term: from 2018 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 391058966

Proper understanding of geophysical processes controlling earthquake rupture propagation is a key point in earthquake hazard mitigation. Slip inversions provide details on rupture propagation by modeling seismic records. However, they are inherently non-unique requiring regularization and typically lacking proper uncertainty estimation. We aim at i) utilizing dynamic rupture modeling to regularize the solution and ii) use a Bayesian approach to capture correctly the uncertainty of the retrieved parameters. To further improve our knowledge about the physical processes affecting the rupture, we will extend the models from finite source inversions to more realistic conditions utilizing the SeisSol software package. This enhanced approach will be applied primarily to selected M~6 events with distinct behaviors in their rupture propagation that are challenging to explain in terms of rheological complexity (segment jumps, large shallow slip, on-fault frictional barriers), and possibly also to a few well-recorded significant (M>6) earthquakes that would occur worldwide during the research period. The proposed research will require the development of new codes for mathematical modeling of the earthquake fault rupture process, modification of existing frameworks and utilization of high-performance computing infrastructure. For the development of kinematic and dynamic slip inversions in the Bayesian framework we will extend kinematic earthquake source inversion codes of the Charles University in Prague (CUP) and develop new ones for dynamic source inversions. To constrain earthquake source processes from observations, we will extend the inferred earthquake source models to large-scale (high-resolution) dynamic rupture scenarios of selected real events. To this aim, we will utilize the SeisSol software package developed at the Ludwig-Maximilians-University Munich (LMU) which allows to incorporate complex, natural fault zones. This proposal for bilateral funding aims to complement expertise of two young researchers in earthquake source physics and ground motion modeling. Combination of expertise of the researchers of the two groups will permit to go beyond standard kinematic source inversions and beyond scenario-based forward dynamic rupture simulations towards the development of fully dynamic finite-extent source models, to perform physically consistent, finite-extent source inversions including evaluation of parameter uncertainties by means of Bayesian inference. The newly developed codes, combining cutting-edge methods for solving the forward and inverse problem, will make use of modern and future high-performance computing infrastructure and will be made fully available to the seismological community worldwide.

• DFG Programme: Research Grants
• International Connection: Czech Republic
• Partner Organisation: Czech Science Foundation
• Cooperation Partner: Professor Dr. Frantisek Gallovic