| 摘要: | 本研究中利用擴充均質地震目錄（homogeneous catalog）與三個孕震震源模型（包括隱沒帶、區域震源、活動斷層）與阿爾巴尼亞（Albania）機率性地震危害度評估重新分析。此種均質地震目錄的分析方法，是之前的研究中未曾考慮的。此擴充地震目錄涵蓋36.0°N46.0°N和16.0°E24.0°E之研究區域，時間尺度上則涵蓋122年從1900年至2022年的地震事件（共計17679次規模大於3.5的地震）。在此架構下，三個孕震震源模型共包括63個區域震源、275條活動斷層，以及兩個隱沒帶系統。此兩個隱沒帶系統分別為海倫島弧（Hellenic Arc）與卡拉布里亞島弧（Calabrian Arc）。本研究的主要特點在於納入擴充地震目錄與隱沒帶震源模型，並基於資料驅動的方法選取地震動模型（GMMs），其中包含最新的全球地震動模型。地震危害度分佈圖以地表加速度峰值（PGA）和譜加速度（SA）的形式呈現，並考慮對應50年內10%和2%的超越概率（PoE），即回歸期為475年和2475年。本研究之結果是根據歐洲耐震規範Eurocode8（EC8）所設定之標準參考場地條件，考慮以上部30公尺土壤層的平均剪力波波速度（Vs30）大於800 m/s，並利用Vs30地圖對地震動放大場址分類。此研究分析阿爾巴尼亞八個城市的地震危害度曲線圖與均布危害度反應譜，並以解構分析判斷不同孕震模型、地震規模與距離之關係、地振動之不確定性對這些選定城市的危害度貢獻。結果顯示，位於阿爾巴尼亞西部沿海的城市，包含杜勒斯（Durres）、非爾（Fier）、夫羅勒（Vlora）和薩蘭達（Saranda），以及首都地拉那（Tirana），面臨高的地震危害度。此研究中所呈現的危害度分佈圖與前人研究之區域性尺度分佈圖結果相當。危害度分佈圖可作為建立新的國家尺度之孕震構造分區的參考指標，並納入城市規劃與災害之準備，也可作為未來地震風險研究的輸入。這也意味著相關主管部門應考慮此研究之結果，在更可靠和現實的基礎上改進現有的設計規範，以提高國家建築的安全水平。;In this study, the probabilistic seismic hazard assessment for Albania was obtained by
implementing the extended homogeneous catalog and three source models, including the subduction zone (along with area sources and active faults), which has not been considered in prior studies. Albania’s earthquake catalog is expanded, covering a study area bounded by 36.0◦–46.0◦N latitude and 16.0◦–24.0◦E longitude for the 122 years time period from 1900 to 2022 (counting 17,679 earthquakes with magnitude ≥ 3.5). The three main seismogenic source models consist of 63 area sources, 275 active faults, and two subduction systems represented by the Hellenic and Calabrian Arcs. The main features of this analysis are the inclusion of the extended catalog, implementation of subduction sources, and the data-driven approach on selecting the ground motion models (GMMs), which includes recent global models. The ground motion hazard maps are presented in terms of peak ground acceleration (PGA) and spectral acceleration (SA), for 10% and 2% probability of exceedance (PoE) in 50 years, corresponding to 475 and 2475 years return period. The results are carried out for rock conditions with average velocity in the upper 30 m of soil section Vs30≥800 m/s, the standard reference site conditions used by the European seismic code EC8 (Eurocode 8 (CEN, 2004)), and counting the ground motion amplification site classes based on Vs30 map (Wald & Allen, 2007). Hazard curves and uniform hazard spectra are estimated for eight cities in Albania, while the disaggregation analysis is conducted to determine the contribution of each seismic source, and magnitude-distance including the range of ground motion uncertainties (epsilon) to the hazard for those eight selected cities. The findings underscore high seismic hazard in cities situated along the western coast of Albania, including Durres, Fier, Vlora, and Saranda, as well as the capital city, Tirana. The hazard maps obtained are comparable with the results on a regional scale. The hazard maps can be a reference indicator to establish a new regulatory national seismic zonation, to be considered for urban planning and disaster preparedness, and be used as an input for future seismic risk studies. This implies that the competent authorities should take into consideration the obtained results to improve the existing design code on a more reliable and realistic basis in order to increase the safety level of construction in the country. |
