[S-CG49] Integrative seismic and secondary hazard/risk assessment

[SCG49-P04] Hazard and Risk-Based Evaluations of Surface Fault Displacement: A Case Study of the Meishan Fault, Taiwan

*Hsun-Jen Liu^1,2, Yu-Wen Chang¹, Wen-Yu Jean¹, Yin-Nan Huang² (1.National Center for Research on Earthquake Engineering, 2.National Taiwan University)

Keywords:Surface Fault Displacement, Probabilistic Approach, Deterministic Approach, Risk Approach, Meishan Fault

In western Taiwan, several north-south transportation systems coexist with numerous active faults. Among these, the Meishan Fault, located in central-western Taiwan, trends east-west and intersects critical transportation infrastructure, including two national highways, a conventional railway, and a high-speed railway. The near-fault effects, especially permanent ground displacement, pose significant risk to these lifeline systems. Moreover, the Meishan Fault has been the source of two severe earthquakes in 1792 and 1906, each with a magnitude of 7.1. In the past two years, the surrounding regions have experienced frequent seismic activity with magnitudes ranging from 3 to 5.5. In response to these hazards, this study conducts deterministic, probabilistic, and risk approaches to evaluate surface rupture displacements along the Meishan Fault, aiming to improve the seismic performance and resilience of structures near or crossing the fault, thereby contributing to sustainable structures.

This study uses the latest fault displacement models (FDMs) from the Fault Displacement Hazard Initiative (FDHI) Project to evaluate the on-fault rupture displacement of the Meishan Fault, such as CEA23 (Chiou et al., 2023) and LA23 (Lavrentiadis and Abrahamson, 2023). The possible geometry and seismic activity parameters for the Meishan Fault are assigned according to the historical documents and in-situ investigation reports. The deterministic approach presents the on-fault rupture displacement along the normalized location. The probabilistic approach illustrates the hazard curve which presents the annual rate of the principal displacement exceeding a specific level. The risk approache collaborates with the fragility curve and presents the on-fault rupture displacement corresponding to a 1% probability of collapse in 50 years. Japanese seismologist Fusakichi Omori's documented surface fault displacement observations from the 1906 Meishan earthquake serve as a key reference for comparison with the results from deterministic, probabilistic, and risk approaches.