Task E: Finite-Fault Simulations


  • To develop a database of low frequency simulated ground motions to supplement the recorded data for CENA using finite-fault models.

The Simulations Working Group will coordinate the validation and forward modeling of ground motion simulation, considering different methods. Because simulations are at the center of the project, the TI team plays a stronger role in the tasks related to the Simulations WG. The Simulations WG relies on input from the Database, Path/Source, and Geotechnical WGs.

The main use of the finite-fault simulations is to guide the development of the general double-corner model and to constrain the scaling of the low frequency behavior for earthquake events not represented in the database (e.g. large magnitudes). The Simulations WG is responsible for selecting the methods for validation and for developing the validation requirements, in collaboration with the TI team. Additional selected methods developed by USGS researchers will be validated as well and considered for use in forward simulations. The WG will also evaluate the finite-fault methods based on the validations (pass/fail). The TI team will review the WG recommendations and make the final decision as to which model(s) will be applied in the forward simulations.

The Simulations WG will coordinate the definition of the inputs for the selected finite-fault simulations. This includes the development of area-magnitude scaling relations for CENA  and the selection of models for kinematic input.

The Simulations WG will also define the cases for forward simulations (earthquake scenarios and station locations). The Simulations WG will conduct initial reviews of the simulation results to compare the results from the different finite-fault modelers, identify areas with significant differences in the ground motions, and identify the causes of the differences in the ground motions. The results of that initial review phase will be presented for discussion at a workshop. The final review of the simulations results including recommendations on which results to use will be presented following the workshop.

The suites of finite-fault simulations will be provided to the Stochastic Simulation Method tasks (F) for use in constraining the low frequency end of the source spectrum.

The results from finite-fault simulation will be made available to GMPE developers to be used as input to their models. The finite-fault simulation results will possibly also be compared to the GMPEs as a consistency check that the finite-fault effects were captured in the implemented general point-source model and carried through the GMPE development.