台灣地區大型崩塌地之地理特性研究

A Study on Geographic Characteristics of Large-scale Landslide Areas in Taiwan Area

郭基賢(Chi-Shien Kuo) ； 楊貴三(Guey-San Yang)

《地圖 ： 中華民國地圖學會會刊》 15期 (2005/07) Pp. 103-114

https://doi.org/10.30006/JC.200507.0009

摘要

台灣位處板塊交接處，地震頻繁、地形陡峭且河流短促，再加上人爲不當開發，往往因地震或颱風帶來之豐沛雨量導致坍塌或土石流，產生災害，造成人員傷亡及財物損失。由於崩塌地具有空間差異性，其與區域地形、地質、氣候及土地利用有關，有鑑於以往的研究僅限於局部區域的細部研究且缺乏全區崩塌地資料庫，以致無法掌握台灣地區大型崩塌地之地理特性，基此本研究擬藉由數化台灣地區五萬分之一地形圖上標示之崩塌地（面積最小爲0.06公頃），並利用地理資訊系統(GIS)套疊台灣地區地質圖、斷層圖、水系、地類植被、道路及40公尺×40公尺數值地形模型(DTM)等圖形資料，以分析探討台灣地區大型崩塌地的地理特性。
經研究成果分析顯示台灣地區大型崩塌地主要分布於高度一千公尺以上及坡度30°-70°間山區，地質屬性多爲砂岩、頁岩、板岩及千枚岩層，而有高達98.5%的崩塌地發生於主要河道旁一公里以內。高度一千公尺以下地區，多發生於水系、道路及人工墾殖地附近，坡度的影響較不顯著；高度一千公尺以上地區，主要影響因素爲坡度、水文、地質及道路開發利用，因此高山地區集水區、林道、產業道路的開發值得相關政府單位審慎評估，以確保國土永續發展。而由本研究成果得知應用地形圖等相關資料來研判崩塌地的地理特性，以提供坡地災害防治參考，似乎具有良好之可行性。

關鍵字

崩塌地 ； 地理資訊系統 ； 地理特性 ； 數值地形模型

並列摘要

Taiwan is located at the connecting place of many plates. Earthquakes frequently happens, terrain is steep as well as rivers are short and intermittent. Besides, people inappropriately cultivate resulting in land collapses and mudflows after earthquake or typhoon. Casualties and lose and damage of property are tremendous. Because landslide areas are characterized by spatial differences, they are related to the area terrain, geology, climate as well as land use. The studies on landslide areas are limited in details of local area and the database of landslide areas are not established in the past. Therefore, geographic characteristics of large-scale landslide areas are not easily controlled. By digitizing marked landslide areas on topography maps of scale 1:50,000 and overlaying geology, fault, hydrographic, vegetation, transportation and DTM of 40m by 40 m layers of Taiwan area with GIS software, the geographic characteristics of large-scale landslide areas in Taiwan are analyzed in this study.
The results show that large-scale landslide areas in Taiwan area are mainly distributed at elevation over 1000 meters and gradient between 30° and 70° mountain area. The properties of geology are mostly Sandstones, Shale, Slate and Phyllite. 98.5 percent landslide areas mainly happen at 1 km within riverside. As for elevation under 1000 meters area, the situations occur at the vicinity of riverside, road and man-cultivated area. The influence of gradient is not significant. As for elevation over 1000 meters area, the major influence factors are gradient, hydrology, geology and developed use of roads. Therefore, the development of water gathering district, logging and production road are needed to be carefully evaluated by related department of government. This will make sure that land can keep developed forever. From this study, applying the information of topographic maps to evaluate the Geographic Characteristics of landslide areas seems show good feasibility and can be provided for references on disaster prevention of hillside fields.

並列關鍵字

Landslide Areas ； Geographic Information Systems ； Geographic Characteristics ； Digital Terrain Model

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