集水區內土地開發利用或自然災害的發生都可能造成土石流之災害，為了有效管理因土石流所造成人民生命財產之損失，對於土石流的來源集水區內崩塌地之分布範圍、面積大小與其出現頻率等特性有必要進行深入的研究。崩塌地發生主要和自然災害、人為開發所引發之崩塌與自然因素造成之崩塌密切相關，其中崩塌地面積大小與出現頻率在特定的面積範圍內遵循著冪次關係(Power law)，但在臺灣與紐西蘭地區的崩塌地並不完全遵循此一特性關係，而是在測量單位範圍內(崩塌地面積介於100-10(5次方)平方公尺)存在兩個冪次關係，可能的原因是由於小規模的崩塌記錄(<1,000平方公尺)受限於先前研究使用航照圖的精確度(比例尺1:25,000)使小規模的記錄有較大的誤差，所以記錄偏少，另外大規模的崩塌則可能是由數個規模較小的崩塌組成而記錄偏高。本研究針對受人為破壞較少的花蓮萬里溪、馬太鞍溪兩條溪流之集水區及其周邊地區進行崩塌地面積與其出現頻率關係之調查，利用精確度較高的航照圖(山地，1:10,000；平地，1:5,000)與Spot6.25公尺解析度之融合色衛星影像，藉由衛星影像處理與地理資訊系統軟體、航照圖判讀以及野外調查來較精確的辨認小規模的崩塌，結果顯示崩塌地面積的大小與其出現的頻率在200-10平方公尺面積範圍內遵循著冪次關係，小於200平方公尺之崩塌地受限於資料之解析度有待進一步的研究。研究結果也顯示利用電腦衛星影像辨認之功能可以降低人工肉眼辨認崩塌地之誤差且大幅縮短崩塌地辨認所需之時間，此一方式對集水區內土地的永續利用將有莫大的助益。

The change of land use and the occurrence of natural hazards, such as typhoons and earthquakes, in river catchments might resu1t in a significant increase in suspended sediment loads. This increase may further affect the cost of water treatment and of maintaining the designed life span of a dam, and may trigger flood or mud/debris flow. The change of river suspended sediment loads is not only caused by fluctuations of river discharges but also by the sources of mud/debris, which are provided by landslides occurring in its catchment area. An understanding of the characteristics of these landslides is crucial for a sustainable catchment management. One of the most important characteristics of landslides is: landslide size distribution, which generally exhibits power-law scaling over a limited scale range (100-10(5次方)square meters), but landslide data sets from Taiwan and New Zealand do not fit a simple power law but exhibit two scaling regimes. This may be due to the limitation of the map resolution of previous studies (aerial photography, 1:25,000) and resu1t in the under sampling of smaller landslides(<1,000 square meters); higher resolution landslide maps wi11 therefore be required. On the other hand, the occurrence of extreme landslide events has been more than researchers expected; this may be the resu1t of mistaking some neighboring smaller landslides for a larger landslide. This project focuses on landslides in less human disturbed Wan-Li-Xi and Ma-Tei-An-Xi river catchments and their neighboring area in Hualien, Taiwan using higher resolution landslide maps (aerial photography, 1:10,000) and spot 6.25m resolution merged satellite images. With the aid of satellite image processing and GIS software and field investigations, smaller landslides could be further identified and studied. The resu1t shows a power-law scaling over a limited scale range of 200-105 square meters landslide areas of more than 30 thousand computer recognized landslides and a better result of using satellite image classification method is hypothesized.