宜蘭縣大同鄉土地利用與坡地崩塌之風險分析

THE RISK ANALYSIS ON THE LANDUSE TYPES AND LANDSLIDES IN TATONG TOWN OF YILAN

李承玫(CHENG-MEI LI) ； 林雪美(HSUEH-MEI LIN)

《工程環境會刊》 39期 (2019/12) Pp. 119-147

https://doi.org/10.6562/JEE.201912_(39).0005

摘要

坡地崩塌為臺灣常見的塊體運動現象，本研究以國土測繪中心的全國土地利用類型資料做為人類成災的承災體特性，而自然條件為該地的孕災環境特性，計算兩者交互作用下產生的災害風險值。宜蘭縣大同鄉土地利用對坡地崩塌的影響，是為「人」對「地」的影響，本研究首先進行因子的篩選，得出土地利用類型、農作距離、道路距離等三項具影響力的因子；接著為「地」對「地」的作用，即自然條件對坡地崩塌的影響，篩選出高程、坡度、坡向、地質、河道距離、一日最大降雨分級和年總雨量等七項因子。前兩個步驟皆著重於「因子」對於「地」的影響評估，目的在於找出可以解釋造成坡地崩塌的影響因子；為了評估其影響力的大小以得出災害風險值，再將篩選得出的土地利用因子與自然條件因子結合，最後將此十項因子合併進行單因子檢驗和羅吉斯迴歸的統計分析，刪除年總雨量和坡向兩者不具解釋力的因子後，則得出解釋力68.3%的模型。本研究藉由統計方法計算大同鄉土地利用與坡地崩塌的風險值後，繪製出大同鄉的災害風險地圖。再以野外考察和居民訪談做防災風險地圖的修正及風險管理的探討，希冀用以達到區域的減災效果。

關鍵字

土地利用類型 ； 坡地崩塌 ； 風險值

並列摘要

Landslide is a common phenomenon in Taiwan. The study defines landuse type data which is from National Land Surveying and Mapping Center as one of the condition of hazard. When landuse types interact with the physical factors of any environment background could yield hazard, and the susceptibility value could be generated. Human-land relationship is the structure in the study. To begin with, the impact of ＂human to land＂ was evaluated by the landuse types to landslide in Tatong town of Iliang. In this procedure, we selected factors by collinearity diagnosis which helps to discover and eliminate multicollinearities. 3 influential factors were obtained, that is landuse types, crop distance and road distance. Secondly, the impact of ＂land to land＂ was assessed by physical factors to landslides, and we acquired 7 influential factors, that is DTM, slope, aspect, geology, river distance, 24 hours maximum precipitation and annual rainfall by collinearity diagnosis as the same. These two steps focus on the evaluation of ＂factors to land＂, and the aim is to find the causal factors which could precisely explain the reason why makes landslide. Moreover, we have to combine the landuse factors and physical factors so that could generate hazard. And then put these 10 factors into univariate tests of association and Logistic regression, after deleted the aspect and annual rainfall factors which is uninterpretable, the 68.3% explanation model was obtained. The study uses statistics methods to demonstrate the susceptibility of landuse type and landslide, by this we could create hazard susceptibility maps in Tatong town. In order to utilize the risk value and risk maps practically.

並列關鍵字

Landuse type ； Landslide ； Risk value