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Developing a Data-centric Workflow for Seismic Source Model Construction and Testing

Description: 

Constructing and calibrating seismic source models for Probabilistic Seismic Hazard Assessment involves integrating disparate datasets into a cohesive whole, amidst substantial incompleteness and uncertainty in most observations. To build seismic source models repeatably, efficiently and with a maximal amount of data, the Global Earthquake Model Foundation has developed an evolving workflow based on open-source tools for modeling crustal fault networks, subduction zones, and distributed seismicity.

Initial fault network characterization is conducted using Oiler, a tectonic block modeling code. Oiler inverts geodetic velocity and geologic slip rate data to estimate fault slip rates and partial coupling at subduction zones. Subfault to multifault ruptures in the fault network are generated using Fermi through graph-theoretic methods, with occurrence rates calculated from fault slip rates and magnitude-frequency distribution (MFD) constraints through a choice of solvers. Shallow off-fault seismicity is modelled by zonal gridded point sources with occurrence rates smoothed according to past seismicity. Subduction zone interfaces and slab sources are modeled separately. The interface is represented by a nonplanar fault surface, accommodating floating ruptures conforming to the MFD derived from the seismic catalog and tectonic convergence rate. The subducted slab is modeled through gridded finite ruptures. Model components derived from instrumental seismicity rely on a homogenized seismic catalog classified to the main tectonic domains by event proximity to surfaces delineating the domains. The model's fidelity to seismicity data is evaluated using Hamlet (Hazard Model Evaluation and Testing), which conducts sanity checks and statistical analyses, comparing simulated seismic catalogs to observed data for the whole model domain, or spatial subdomains, individual logic tree branches, or source typologies. Hamlet can also address the goodness of fit of each epistemic uncertainty hypothesis expressed via the source model logic tree. We present use cases of these tools in models of different sizes and regions.

Session: Regional-Scale Hazard, Risk and Loss Assessments - II

Type: Oral

Date: 5/2/2024

Presentation Time: 02:15 PM (local time)

Presenting Author: Richard

Student Presenter: No

Invited Presentation: 

Authors