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Posterior Exploration of Bayesian Kinematic Finite-Fault Earthquake Source Models

Description: 

The Bayesian inversion framework for earthquake source imaging yields an ensemble of posterior models, as opposed to conventional inversion methods that produce individual optimal solutions. Yet, using Bayesian posterior solutions for predicting stress and displacement fields, and their associated uncertainty has been under-explored. Here, we quantitatively characterize the uncertainty structure and predictive observables of kinematic finite-fault earthquake rupture models from published Bayesian inversions for several large megathrust earthquakes, including 2011 Mw9.0 Tohoku, 2014 Mw8.1 Iquique, 2015 Mw8.3 Illapel, 2016 Mw7.8 Pedernales, and 2015 Mw7.8 Gorkha. These events can be grouped into distinct types according to slip patterns: tsunamigenic (Tohoku, Illapel), no trench-breaking (Iquique, Pedernales, and Gorkha), and multi-patch (Illapel) rupture scenarios. Employing homogeneous and layered elastic structures, we compute and compare surface deformation and normal and shear stress on the fault plane for each event. In all cases, surface deformation manifests itself in a transitional way with uplift occurring closer to the trench and smaller subsidence effects in the down-dip direction. Compact large vertical seafloor deformation is prominent for events with tsunamigenic slip. Distributions of significant rupture observables are usually confined to the area directly above the prescribed fault geometries. Stress change appears to be event-dependent due to variable rupture patterns across events. We will leverage posterior model ensembles to rigorously evaluate error propagation in surface displacement and stress change, address how error varies as function of distance from the trench, and evaluate scale-dependent correlation between model parameters. Future work will include computing elastodynamic ground motion and stress changes during these events.

Session: Characteristics and Mechanics of Fault Zone Rupture Processes, from Micro to Macro Scales [Poster Session]

Type: Poster

Date: 5/2/2024

Presentation Time: 08:00 AM (local time)

Presenting Author: Jose

Student Presenter: Yes

Invited Presentation: 

Authors