The Role of Citrus Groves in Rainfall-Triggered Landslide Hazards in Uwajima, Japan
The Role of Citrus Groves in Rainfall-Triggered Landslide Hazards in Uwajima, Japan
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DOI：
10.3390/w14132113
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发表时间：
2022-07
期刊：
影响因子：
3.4
通讯作者：
N. Lusiana;Yoshinori Shinohara
中科院分区：
文献类型：
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作者：
N. Lusiana;Yoshinori Shinohara
山体滑坡经常造成死亡和严重的经济损失。一般来说，森林由于树根的稳定作用，在降低滑坡概率方面起着重要的作用。虽然果树和森林一样是由树木组成的，但是实际的土地管理，如工人对田地的频繁践踏和对地形的压缩，与森林相比，可能会导致这些土地容易发生滑坡。果园在丘陵地区分布广泛，但对其在滑坡发生中的作用研究较少。本研究旨在填补这一空白，评估日本宇和岛市部分地区降雨引发山体滑坡的诱发条件和触发条件。由于2018年7月的强降雨事件发生了大量的山体滑坡，柑橘林占据了研究区域的50%左右。在本研究中，我们将地理数据与回归模型相结合，对丘陵地区果园的滑坡危险性进行了评估。我们开发了五个条件因子的地图：坡度、坡向、归一化植被指数（NDVI）、土地利用和地质。从坡度、坡向、NDVI和地质特征等方面分析，柑橘林滑坡面积密度大于森林。根据不同的降雨指数（1 h、3 h、12 h、24 h最大降雨量和总降雨量）和不同的土地利用方式（森林或柑橘林）以及其他4个条件因子建立了10个logistic回归模型。结果表明，在所有模型中，“柑橘林”都是显著的正系数因子，而“森林”是负系数因子。这些结果表明，研究区柑桔林发生滑坡的概率高于森林。针对不同地点、不同类型的果园和不同降雨事件进行类似研究，对于推广果园滑坡灾害分析至关重要。
Landslides often cause deaths and severe economic losses. In general, forests play an important role in reducing landslide probability because of the stabilizing effect of the tree roots. Although fruit groves consist of trees, which are similar to forests, practical land management, such as the frequent trampling of fields by laborers and compression of the terrain, may cause such land to become prone to landslides compared with forests. Fruit groves are widely distributed in hilly regions, but few studies have examined their role in landslide initiation. This study aims at filling this gap evaluating the predisposing and triggering conditions for rainfall-triggering landslides in part of Uwajima City, Japan. A large number of landslides occurred due to a heavy rainfall event in July 2018, where citrus groves occupied about 50% of the study area. In this study, we combined geodata with a regression model to assess the landslide hazard of fruit groves in hilly regions. We developed maps for five conditioning factors: slope gradient, slope aspect, normalized difference vegetation index (NDVI), land use, and geology. Based on these five maps and a landslide inventory map, we found that the landslide area density in citrus groves was larger than in forests for the categories of slope gradient, slope aspect, NDVI, and geology. Ten logistic regression models along with different rainfall indices (i.e., 1-h, 3-h, 12-h, 24-h maximum rainfall and total rainfall) and different land use (forests or citrus groves) in addition to the other four conditioning factors were produced. The result revealed that “citrus grove” was a significant factor with a positive coefficient for all models, whereas “forest” was a negative coefficient. These results suggest that citrus groves have a higher probability of landslide initiation than forests in this study area. Similar studies targeting different sites with various types of fruit groves and several rainfall events are crucial to generalize the analysis of landslide hazard in fruit groves.