Extended Finite-Fault Ground Motion Modeling Framework: Sensitivity Analysis of Number of Sub-Faults
Description:
Ground motion stochastic simulations are essential for various engineering applications, specifically in seismic hazard assessment and calibration of ground motion models (GMMs). Such simulations are often employed for the purpose of augmenting regions with deficit earthquake datasets. Also, these simulations are often affected by various seismological parameters of source, path and site. Thus, the present study optimizes the seismological parameters stress drop (source) and kappa (site) and performs sensitivity analysis of the number of sub-faults. For the calibration of parameters and sensitivity analysis, a subset of the NGA West2 database (particularly for the California region) is employed. We utilized a total of 600 events and 4,615 records for Moment magnitude (Mw) > 3 and Joyner Boore distance (RJB) < 100 km. The optimal value of stress drop and kappa was determined using grid search procedure. Our observations indicate that as the number of sub-faults within simulations increases, the optimized stress drop value tends to decrease. Further, increasing the number of sub-faults was found to have a negligible effect on the residuals (i.e. log(PSAobs/PSAsim)), only adding to the computational burden and complexity. Thus, our study suggests use of one sub-fault for similar simulations. We also performed comparison with NGA-West2 GMMs (Abrahamson et al., 2014; Boore et al., 2014; Campbell and Bozorgnia, 2014; Chiou and Youngs, 2014; Idriss, 2014) and found consistent results with the GMSS2.0 simulations for different numbers of sub-faults. Thus our findings provide valuable insights to improve the GMMs by optimizing stress drop, kappa and reducing the computational resource and time.
Session: Physics-Based Ground Motion Modeling [Poster Session]
Type: Poster
Date: 5/3/2024
Presentation Time: 08:00 AM (local time)
Presenting Author: Omkar
Student Presenter: Yes
Invited Presentation:
Authors
Omkar Singh Presenting Author Corresponding Author omkar.singh@iitgn.ac.in Indian Institute of Technology Gandhinagar |
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Extended Finite-Fault Ground Motion Modeling Framework: Sensitivity Analysis of Number of Sub-Faults
Session
Physics-Based Ground Motion Modeling