Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/33769
標題: 草嶺大型順向坡崩塌地形演化之研究
A Study of Terrain Evolution on Large Dip-Slope Landslide at Tsau-Lin Area
作者: CHENG, HSIN-HSING
鄭新興
關鍵字: 數值地形模型;DTM
出版社: 水土保持學系
摘要: 
Abstract
Since Taiwan is located on a global shell, mountain areas and faults usually form dipslope topography. After the bank of the valley is eroded, earthquakes and heavy rainfall can easily cause mass wasting and huge disasters. The Tsau-Lin landslide was one typical and complete case. Of all the landslides, the hundred year frequency “9/21” earthquake in 1999 in Taiwan caused dramatic collapse and landslide dams. It has attracted attention from all over the world. Fortunately, the “7/2 Flood” in 2004 relieved the potential dangers.
This study focuses on the history of Tsau-Lin dipslope with repeated wasting and geomorphologic change after 9/21 earthquake using aerophotography and remote sensing, global positioning system, geographic information system and technology overlay analysis. According to the increase of soil, water and sand accumulation of mass wasting, we are able to estimate longterm speed of slope and riverbed erosion and understand the mechanism and trend of the collapse. Utilizing the yearly graphic information, we can correctly provide an effective analysis and research of geomorphologic evolution. Based on geologic uniform variation theory, we can research the dramatic change process of the Tsau-Lin area before and after 9/21 earthquake. Through collecting information about different geomorphologic evolutions, we are capable of applying these to prevent further diasters. The results and findings are as following:
1. Shale and sand inter-bedding dipslope usually cause the most dramatic land movement and the fastest collapse. Since Taiwan's land is still young, it will cause frequent shell movement. This research uses single GPS control point to form Tsau-Ling area DEM(digital elevation model) information. The clarity of the result can fit in the need of huge landslide and collapse analysis. According to the DEM, the geomorphologic sensitive zone under frequent storms and earthquakes, the collapses represent certain evolution rules.
2. This study makes use of various historical information of Tsau-Lin mass wasting, satellite observation and geographical system to establish a complete process flowchart. It controls and monitors the characteristics of the dipslope topography, foretelling the possible future land changes and provides decision supporting of disaster prevention for the government.
3. In order to realize the historical changes of mass wasting lnad in the
Tsau-Lin area, we use map, paper map, Japan occupied stage and
topographic maps. After digitized satellite DEM analysis and
comparison, it is easy to understand the land change through calculation
geographical information system.
4. Tsau-Lin area's huge landslide caused by storms and earthquakes can be
described by the cycle evolution process as following:
5. The slope change of Tsau-Lin area, according to the recent five years' analysis and comparison, the reason of the collapse was still mainly controlled by the land type rather than the stormy type mass wasting.
6. After the 9/21 Tsau-Lin landslide, the government's effect of applying disaster support toward natural land changes was limited. This research utilizes satellite observations and global geographical information systems to establish standard models and process flowcharts in order to provide as emergency process for the possibility of future landslides.

摘 要
台灣島係由歐亞大陸板塊與菲律賓海板塊擠壓隆起而成,因地殼變動劇烈,使以沉積岩為主要地層之台灣島發生褶皺與斷層而常形成順向坡地形,在河岸基脚不斷被淘刷而形成自由端後,每遇地震與豪雨即生大規模之崩塌並造成災害,草嶺山崩乃一典型且資料完整之案例。尤其於1999年發生百年頻率之九二一大地震時草嶺再次發生大規模崩塌並造成堰塞湖,2004年之七二洪水已將其沖散而化解了其潛在危險。
本研究即針對草嶺順向坡之地形發生一崩再崩之歷史與九二一大地震後地形之演變,以航遙測影像,透過全球定位系統(GPS)之輔助及地理資訊系統(GIS)技術所建立歷年較精確而完整之系列圖資成果,藉套疊分析歷次崩塌之土石方量、堰塞湖蓄水量、泥砂量及其消長情形,以估計長年以來之邊坡及河道沖蝕速率,並瞭解其崩塌之機制與趨勢,將所獲得歷年完整之圖資,據以提供較精確及高效率之地形演化分析與研究。以地質均變學說及地形演化理論為基礎,詳細探究九二一大地震前後草嶺地區劇變之過程,進而推求歷次崩塌之地形演化相關資訊,以鑑往知來並供防災應用。茲述其主要成果如後:
一、 本研究獨採「以單一組GPS控制點推算產製之歷年各期DEM資料」,其精度符合地形分析之需求,所建立之地形演化相關圖資,可精確瞭解台灣地形之演變,除從簡要地圖、紙圖、或以日據時代所建立之台灣早期地形圖經數化後,與現今由航測製圖產生之DEM進行套疊分析比對,可輕易地瞭解地形之演變,且藉由GIS之相關功能即可進行快速分析及量化計算。
二、 台灣之山地常受地震及豪雨侵襲,於造成大山崩後其自然地形之輪廻演替之演變過程可以下式進行描述:
式中以 之後退係數b為地形演化之主要控制因素,由本研究所建立草嶺地區近百年來連續崩塌之資料,分析結果顯示砂頁岩互層之順向坡崩塌的大量土砂移動,係地形演化之主因。
三、 具砂頁岩互層地層之順向坡地形,其崩塌速率及其規模較大,常係地表活動中土砂移動最劇烈並常造成災害者,由於台灣地質年代輕、地殼活動仍然相當頻繁,且在豪雨及地震不斷的條件下,對砂頁岩互層且敏感之順向坡地形區之崩塌現象,本研究分析並獲得其演化之定則為:(一)草嶺大崩塌 自1999年因九二一大地震崩塌後其崩塌坡面之變化,經五年來逐年分析比對之結果,其崩塌特性主要仍受具砂頁岩互層地層之特性所左右。(二)自1903~2004年約百年間由於主要豪雨及地震兩種作用外力之特性不同,呈現不同之崩塌規模:豪雨型崩塌之規模較小且只有局部地層崩裂滑動;地震型崩塌則為整層崩解。
四、 九二一大地震草嶺發生大崩塌後政府及各方所採行之各項措施,由於對自然地形變遷之資訊未能全然掌握而採取更完妥之做法。本研究由所蒐集完整之崩塌歷史資料及史料記載,以航遙測、GPS及GIS等科技深入探討及分析其相關地形變遷之過程,可充分掌握順向坡之地質與地形演變之特性並預測未來地形之劇烈演變,且已建立其完整之作業模式及處理流程,其結果與經驗可提供政府往後在有類似大型崩塌發生或在山坡地發生土石災害時之防救災決策支援上應採何種因應處理之參考。
URI: http://hdl.handle.net/11455/33769
Appears in Collections:水土保持學系

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