分析結果顯示，台北中小地震與設計地震的代表規模分別為Mw = 6.75與Mw = 6.95，較規範提供之Mw = 7.1與Mw = 7.3略低，高雄則分別為Mw = 6.85與Mw = 6.55~6.85，亦低於規範值。液化安全係數分析顯示，若採用本研究推估之地震規模，台北與高雄地區安全係數分別較規範提高約1.09~1.16倍，顯示現行規範在地震規模設定上具保守傾向。 ;This study aims to evaluate the appropriateness of the earthquake magnitudes adopted for soil liquefaction potential assessment in the “Seismic Design Specifications and Commentary of Buildings”. The research methodology is based on Probabilistic Seismic Hazard Analysis (PSHA), utilizing deaggregation to determine the earthquake magnitudes that contribute most significantly to seismic hazard under medium-small earthquakes (30-year return period) and design earthquakes (475-year return period). The study focuses on two regions, Taipei and Kaohsiung, incorporating seven sets of Ground Motion Prediction Equations (GMPEs) and three cutoff magnitude thresholds for sensitivity analyses. Additionally, the HBF method is employed to calculate the liquefaction safety factors.
The results indicate that the representative earthquake magnitudes for Taipei are Mw = 6.75 for medium-small earthquakes and Mw = 6.95 for design earthquakes, which are slightly lower than the specification values of Mw = 7.1 and Mw = 7.3. In Kaohsiung, the representative magnitudes are Mw = 6.85 and Mw = 6.55~6.85, also lower than the specification values. Liquefaction safety factor analysis reveals that adopting the magnitudes obtained in this study would increase the safety factors by approximately 1.09 to 1.16 times compared to those based on the current code, suggesting that the existing specifications adopt a conservative approach to earthquake magnitude settings.
