地震引致之山崩條件式機率預測模式-以集集地震為例

Abstract

臺灣位處於地殼變動激烈之處，因為地勢陡峭加上人口密集，災害性之山崩經常發生，對人民生命財產造成威脅，政府也每每投入大量人力物力於災區中，造成財政上的困難。故若能有效預測地震引致山崩可能發生地區，將能提供決策者關於規劃土地利用及災區重建之參考。本研究擬以條件式機率統計方法建構一套山崩潛勢分析模式，以各種影響因子組合之山崩潛勢分析成效決定山崩預測之影響因子組合，並建立山崩預測模式，繪製山崩預測圖，期能對防災計畫、土地利用計畫之擬定有所助益。 本研究使用條件式機率統計方法，採用921集集大地震之地震資料與崩塌圖層，並收集處理研究區域之地理空間資料，配合自行以Visual Basic撰寫之應用程式與地理資訊系統軟體ArcView，建構山崩潛勢模式及山崩預測模式，並使用實際崩塌範圍與潛勢分析及預測分析進行驗證，對於解釋模式成效之優劣更具物理意義。 彙整研究區域內山崩潛勢分析與山崩預測之結果，顯示以坡度、坡向及地質即可建立成效良好之山崩預測模式，其山崩預測圖面上，大部分及較大面積的崩塌區域皆可被涵蓋或鄰近於高山崩發生可能性之區域，亦證明山崩預測成效指標等模式驗證方式之適用性。

Taiwan locates in the circum-pacific seismic zone with frequent earthquake activities, which could induce the hazardous landslides. An effective landslide prediction map could provide an important reference for policymaking for land use regulation and drafting of mitigation measures of potential disastrous area. The geographic information system database of the research area was constructed by colleting geology and geomorphology data and the landslide scars triggered by Chi-Chi earthquake of research area. Furthermore, the Conditional Probability method was utilized to construct landslide potential model and prediction model. Based on the results of landslide potential analysis, the best factor combination for landslide prediction analysis was determined. Verification of results from the landslide potential and prediction analysis was performed using landslide scars of research area, and success rate of analysis could be quantified. The results of landslide prediction analysis indicate that using the aspect, slope and geology factors, could properly build up a distinguishing landslide prediction model. The landslide scars in the landslide prediction map coincide well with the high landslide probability area. Furthermore, the results of comparisons also prove the suitability of verification method used in this research.