以不同地形資訊探討草嶺地區地形之變遷

A Study on Landform Changes of the Tsaoling Landslide Area by a 60-year Map Comparison from 1930s to 1990s

鄭新興(Hsin-Hsing Cheng) ； 陳文福(Wen-Fu Chen) ； 蔡喬文(Chiao-Wen Tsai)

《臺灣地理資訊學刊》 1期 (2004/10) Pp. 63-78

https://doi.org/10.29790/JTGIS.200410.0005

摘要

草嶺曾發生過四次大規模之崩塌，尤其1999年9月21日之集集大地震，所引發第四次崩山之規模最大，其大量崩落土石阻斷了清水溪之水流，再次形成堰塞湖（新草嶺潭）由於堰塞湖常因潰壩而造成下游地區嚴重災害，故也曾造成一陣恐慌。倘能對其早期至今之地形變化進行了解，並對早期紙圖與現有數值地形圖之不同地形資訊加以比較，必能有益於對其現況之處理及未來再崩塌時處理決策訂定之參考。
本研究以臺灣地形圖（1930年）、1998年及1999年航空像片，分別製作成數值高程模型(DEM)，進行自1930年至1998年共68年間的地形變遷分析，以有助於對崩塌區更原始地形之了解。由早期紙圖經過平面校正後發現未變化區域之地形走向大致符合1998年之正射影像，且1998年比1930年的崩塌區多增三處，係爲1941年與1979年兩次崩塌所造成；且河道由左岸向右岸偏移約360m，河道明顯向右岸順向坡之基腳持續侵蝕，岩層下端受到掘鑿作用失去支撐而形成自由端，岩層邊坡經雨水之浸潤與地震持續之搖撼而失去平衡，造成堀畓山持續崩至倒交山。由於早期紙圖之製圖過程與現代航測製圖方式不同，所產生誤差之原因甚多，必須經過誤差檢定與校正，方可做更精確的量化分析。

關鍵字

草嶺 ； 臺灣地形圖 ； 堀畓山 ； 地形變遷 ； 數值高程模型

並列摘要

The Tsaoling Landslide Area has had four serious collapses in history. Above all, the scale of the Chi-Chi Earthquake that occurred on September 21-tb of 1999 caused the fourth collapse to be the biggest down cover earth mass and stone blocking the Ching-Shui Stream and forming the New Tsaoling Lake. Since the barrier level of the lake may breach due to breaking down calamity and panic may occur down stream. If we compare the Maps from 1930 to 1990 and investigate the landform change, it will help us create a better policy to treat mass collapses.
This study has gathered maps for a period of over 60 years between 1930 and 1996 to build a DEM dataset that will allow an analysis of the Tsaoling Landslide Area landform change and a better understanding of the present-day and earlier landform characteristics. After plane-proof reading the area, we discovered that the unchanged area of the fanner map is similar to the landform of 1998. The three sites of newly collapsed of 1988 after 1930 was inferred from the collapsed al 1941 and 1979. The location of the river moved approximately by 360m from the left bank to the right bank, and the bottom of the consequent slope of the rock stratum in the right bank was eroded. It has formed a free end of rock stratum in Kuh-Lum Mountain and after the water eroded the rock stratum was unbalanced and then caused a landslide triggered by rains and quakes. Due to some errors on two different occasions, plane and elevation check and adjustment must be introduced to perform a precise analysis.

並列關鍵字

Tsaoling ； Taiwan terrain map ； Kuh-Lum Mountain ； landform changes ； digital elevation modeling

參考文獻

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