Development of a PFDHA Framework for Taiwan: Comparative Assessment of Models using Recent Surface Ruptures and Hazard Mapping

Taiwan is situated in a highly active tectonic zone where dense active faults pose significant risks of permanent ground deformation to critical infrastructure, particularly reservoirs and dams located in the near-fault domain. While Probabilistic Seismic Hazard Analysis (PSHA) regarding ground motion is well-established in Taiwan, a systematic framework for Probabilistic Fault Displacement Hazard Analysis (PFDHA) remains to be developed. This study aims to establish a PFDHA framework tailored to Taiwan's geological setting by evaluating the applicability of existing international empirical models against local observation data and generating the first Fault Displacement Hazard Map for the region.

To select the most appropriate prediction models for Taiwan, we analyzed high-resolution surface rupture data from two significant recent events: the 2018 Mw 6.4 Hualien earthquake and the 2022 Mw 6.9 Chihshang (Taitung) earthquake. We compared these observations against a suite of international empirical prediction equations, ranging from established models (e.g., Petersen et al., 2011) to the most recent developments (e.g., Lavrentiadis et al., 2023; Kuehn et al., 2024; Visini et al., 2025; Chiou et al., 2025). Through statistical analysis, we evaluated the goodness-of-fit of these models across different fault types and magnitudes to identify those that best capture the rupture characteristics of Taiwan's complex fault systems.

Based on the model comparison results, we utilized the OpenQuake engine to compute a preliminary island-wide Fault Displacement Hazard Map for Taiwan. Furthermore, we conducted a site-specific PFDHA for a reservoir located adjacent to an active fault, deriving displacement hazard curves for engineering applications. This study highlights the comparative performance of cutting-edge international models in the Taiwan region and provides a crucial empirical foundation for future infrastructure design and risk mitigation in areas prone to fault displacement.