2008/5/12四川省汶川發生地震規模Ms 8.0，震源深度10公里，肇因於龍門山斷層近300公里之逆衝斷層破裂，斷層上盤由西北向東南逆衝，斷層位移量平均約6公尺，如此大規模的地震除因為強烈地表震動與斷層破裂直接造成結構物破壞之外，而龍門山斷層西北側之上盤屬高山區，地形陡峻，淺層地質破碎，於山區水庫集水區內因強震而誘發大規模之崩塌地，將造成後續次生災害威脅。由於衛星影像解析度日益提升且成本降低，本研究以四川省北川地區為研究區，主要採用福爾摩沙二號衛星(FORMOSAT-2)與ASTER多光譜影像進行災情判釋，輔以TerraSAR雷達影像彌補雲遮及陰影區域判釋，進行災區影像變異分析及土砂災害自動判釋，期能透過遙測技術與多尺度衛星影像資訊之綜合應用，建立廣泛區域之土砂災害監測機制，文中將以多元尺度遙測分析方法，評估四川省汶川地震後強震區內，崩塌地、河道擴張、堰塞湖等各類型土砂災害之情況，並試述後續可能致災之影響區域。

An earthquake of Ms 8 struck Wenchuan County, western Sichuan, China on May 12th, 2008. This devastating earthquake was caused by Longmen Shan thrust belt with more than 300km fault rupture. The displacement of the Longmen Shan fault is 6m in average. The large ground motion of Wenchuan Earthquake did not only damage the buildings and killed more than 70,000 people, but also caused huge amount of landslides in the mountainsides. Therefore, the geohazards monitoring will be also the important issue after Wenchuan earthquake. This study area is located in the Bei-Chuan of Sichuan province. In order to evaluate the geohazards of Wenchuan Earthquake rapidly, the spectrum images of FORMOSA-II, TerraSAR, and ASTER satellites was adopted for interpreting the landslide area and the reservoirs of the landslide dam. The pair of images of ASTER satellites was adopted for producing the DEM. Furthermore, the satiability of the landslide dam was evaluated by extracting the elevation from DEM and the calculating the area of landslide dam reservoir in GIS. From the experience of this case study, using multi-scale satellite images could provide information for geohazard mitigation planning rapidly, and prevent damage and reduce loss validly.