3:30 PM - 5:00 PM
[HDS09-P06] Strong motion prediction incorporating detailed geometry of active faults: Application to Byobuyama-Enasan and Sanageyama fault zone
Keywords:strong motion prediction, active faults, seismic hazard evaluation
Detailed information of active-fault survey results contributes to improvement of the accuracy of near-fault strong-motion prediction, including displacement distribution. We are working on incorporating the detailed geometry of active faults to strong-motion prediction models through the collaboration between active-fault and strong-motion research groups.
In this presentation, we report the tentative results of strong-motion prediction incorporating the detailed geometry of active faults, which is a part of the work supported by the MEXT “Comprehensive Research Project for the Byobuyama - Enasan and Sanageyama Fault Zone”.
In this work, the fault model for strong-motion prediction is divided into two parts: “deeper part” within the seismogenic zone and “shallower part” that is in between the seismogenic zone and the ground surface. For the deeper part of the fault model, the location and rectangular-shaped geometry is set by referring to the fault survey results, and its rupture parameters are modeled in the framework of the characterized source model of the “strong-motion prediction recipe” (HERP 2020). For the shallower part of the model, active fault trace data obtained from tectonic geomorphological survey was used to model the geometry. The trace dataset was first approximated by segments of 100 – 500 m length, and then connected with the top of the deeper part of fault. The entire fault model was discretized into 100 m-interval point sources.
Using the fault model, we computed broadband strong motion for the Byobuyama - Enasan and Sanageyama fault zone in the central Japan by a hybrid approach of 3-D finite-difference method (> 1 s) and the stochastic Green’s function method (< 1 s) using a detailed 3-D velocity structure model around the fault zone (Senna et al., JpGU2023). Continuous collaboration is needed to further investigate the appropriate fault models incorporating detailed active fault information including slip and slip-rate distribution.
Acknowledgements: This research was supported by the MEXT “Comprehensive Research Project for the Byobuyama - Enasan and Sanageyama Fault Zone”.
In this presentation, we report the tentative results of strong-motion prediction incorporating the detailed geometry of active faults, which is a part of the work supported by the MEXT “Comprehensive Research Project for the Byobuyama - Enasan and Sanageyama Fault Zone”.
In this work, the fault model for strong-motion prediction is divided into two parts: “deeper part” within the seismogenic zone and “shallower part” that is in between the seismogenic zone and the ground surface. For the deeper part of the fault model, the location and rectangular-shaped geometry is set by referring to the fault survey results, and its rupture parameters are modeled in the framework of the characterized source model of the “strong-motion prediction recipe” (HERP 2020). For the shallower part of the model, active fault trace data obtained from tectonic geomorphological survey was used to model the geometry. The trace dataset was first approximated by segments of 100 – 500 m length, and then connected with the top of the deeper part of fault. The entire fault model was discretized into 100 m-interval point sources.
Using the fault model, we computed broadband strong motion for the Byobuyama - Enasan and Sanageyama fault zone in the central Japan by a hybrid approach of 3-D finite-difference method (> 1 s) and the stochastic Green’s function method (< 1 s) using a detailed 3-D velocity structure model around the fault zone (Senna et al., JpGU2023). Continuous collaboration is needed to further investigate the appropriate fault models incorporating detailed active fault information including slip and slip-rate distribution.
Acknowledgements: This research was supported by the MEXT “Comprehensive Research Project for the Byobuyama - Enasan and Sanageyama Fault Zone”.