Landslide Susceptibility Mapping along Bhalubang–Shiwapur Area of Mid-Western Nepal Using Frequency Ratio and Conditional Probability Models   总被引：3，自引：3，他引：0  

Amar Deep Regmi  Kohki Yoshida  Hamid Reza Pourghasemi  Megh Raj DhitaL  Biswajeet Pradhan 《山地科学学报》2014,11(5):1266-1285

Roads constructed in fragile Siwaliks are prone to large number of instabilities. Bhalubang–Shiwapur section of Mahendra Highway lying in Western Nepal is one of them. To understand the landslide causative factor and to predict future occurrence of the landslides, landslide susceptibility mapping(LSM) of this region was carried out using frequency ratio(FR) and weights-of-evidence(W of E) models. These models are easy to apply and give good results. For this, landslide inventory map of the area was prepared based on the aerial photo interpretation, from previously published/unpublished reposts, and detailed field survey using GPS. About 332 landslides were identified and mapped, among which 226(70%) were randomly selected for model training and the remaining 106(30%) were used for validation purpose. A spatial database was constructed from topographic, geological, and land cover maps. The reclassified maps based on the weight values of frequency ratio and weights-of-evidence were applied to get final susceptibility maps. The resultant landslide susceptibility maps were verified andcompared with the training data, as well as with the validation data. From the analysis, it is seen that both the models were equally capable of predicting landslide susceptibility of the region(W of E model(success rate = 83.39%, prediction rate = 79.59%); FR model(success rate = 83.31%, prediction rate = 78.58%)). In addition, it was observed that the distance from highway and lithology, followed by distance from drainage, slope curvature, and slope gradient played major role in the formation of landsides. The landslide susceptibility maps thus produced can serve as basic tools for planners and engineers to carry out further development works in this landslide prone area.  相似文献   

Projected climate change impacts on vegetation distribution over Kashmir Himalayas   总被引：1，自引：0，他引：1  

Irfan Rashid  Shakil Ahmad Romshoo  Rajiv Kumar Chaturvedi  N. H. Ravindranath  Raman Sukumar  Mathangi Jayaraman  Thatiparthi Vijaya Lakshmi  Jagmohan Sharma 《Climatic change》2015,132(4):601-613

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Weathering and mineralogical variation in gneissic rocks and their effect in Sangrumba Landslide,East Nepal     

Amar Deep Regmi  Kohki Yoshida  Megh Raj Dhital  Biswajeet Pradhan 《Environmental Earth Sciences》2014,71(6):2711-2727

Sangrumba landslide is one of the largest and the most active landslides in Nepal Himalaya. Geologically the landslide belongs to the Higher Himalaya and consists of Pre-Cambrian biotite–garnet and sillimanite gneiss with some quartzite. The present paper aims at describing various degrees of rock weathering and their effect in Sangrumba landslide. Field study followed by mineralogical, geochemical and geotechnical analyses of the collected rock and soil samples from the landslide zone were used in characterizing weathering degree. The gneisses are intensely weathered while quartzite is unweathered. Petrographical and X-ray diffraction analyses showed that the rocks in the landslide zone had undergone weathering process with the formation of different types of clay minerals as kaolinite, vermiculite, smectite and chlorite. This was further confirmed by the Scan Electron Microscope and Energy Dispersive X-ray analyses. These clay minerals drastically reduced the rock strength facilitating the extensive failure of the Sangrumba landslide. The major and trace element composition of the rock and soil samples was calculated from the XRF analyses. The geochemical analyses and weathering indexes of rocks showed that they are significantly weathered and had a major influence in the formation of the Sangrumba landslide. In addition, mechanical strength measurement of rock/soil showed that the strength drastically decreases as the weathering intensity increases. Rainfall followed by the rock type are the most dominant parameters influencing the weathering process which leads to the formation of large landslide as the present one. These findings can be used in other areas with similar geological and topographical conditions.  相似文献   

Slope aspect effects of loess slides and its spatial differentiation in different geomorphologic types   总被引：1，自引：0，他引：1  

Haijun Qiu  Amar Deep Regmi  Peng Cui  Sheng Hu  Yanmin Wang  Yi He 《Arabian Journal of Geosciences》2017,10(15):344

Several researchers have evaluated landslide susceptibility using various factors, and only few have focused on only one landslide impacting factor in detail, especially its response to geomorphologic evolution. Slope aspect is one of the key conditioning factors for landslide susceptibility assessment in fine-scale studies. To elucidate the slope aspect effect of loess slides and its spatial differentiation, we selected three study areas with different geomorphologic settings in the Chinese Loess Plateau, and developed landslide inventory through the interpretation of remote sensing images and intensive field survey. By using GIS and statistical approach, including extreme ratio and coefficient of variation, we characterized the distribution of loess slides in different slope aspects and compared their spatial differentiation. The results showed that the slope aspect has a significant influence on the spatial distribution of loess slides. The number and area of loess slide is higher in south-facing slope in all the three counties. Moreover, the slope aspect effects on loess slides were mediated by the geomorphologic types. The more mature the development of geomorphology, the more obvious is the slope aspect effect on the landslide. This study is very important for the study on geomorphologic evolution of Loess Plateau.  相似文献