Copy of PhD Thesis
If you are interested to have copy of my PhD thesis entitled "Evaluation of rainfall-induced landslides from the perspectives of stability analysis, rainfall threshold and hazard in the Nepal Himalaya and Shikoku, Japan", you can order B/W or color copy of the thesis through this site.
Synopsis of the thesis
The Nepal Himalaya and Shikoku Island are facing tremendous damage to lives, property, infrastructure, and environment due to the monsoon rainfall- and typhoon rainfall-triggered landslides, respectively. In this Ph.D. research, rainfall-induced landslides of the Nepal Himalaya and Shikoku Island are evaluated in three perspectives: hydrological and slope stability modelling, rainfall threshold of landslides, and landslide hazard study. This Ph.D. is exclusively covering almost all issues of rainfall-induced landslides of the Nepal Himalaya and Shikoku Island. The hydrological and slope stability study is performed from the physically based models as per the physical-mechanical law of conservation of mass, energy, momentum and the equilibrium of forces. Thus, available GeoSlope software package and self-prepared heuristic approach were used for hydrological and slope stability modelling. For the rainfall threshold of landslides in the Nepal Himalaya and Shikoku Island, empirical relationships were developed and they were correlated with global rainfall threshold of landslides. Statistical and deterministic hazard modelling has been done to perform rainfall-induced landslides hazard evaluation in the Nepal Himalaya and Shikoku Island.
Applications of hydrological and stability model in the ideal terrains of the Lesser Himalaya of Nepal and north east Shikoku suggested that soil characteristics, low internal friction angle of fines in soil, the presence of clay minerals, bedrock hydrology, and human intervention were the main contributing parameters for slope failures. The clay mineralogy of slope materials is also a contributing factor for rainfall-triggered landslides in both Shikoku and the Nepal Himalaya. In northeast Shikoku of western Japan, typhoon rainfall of one or two days is always responsible for shallow slope failures. When rainfall threshold of landslides is considered for research, in total 677 landslides occurring from 1951 to 2006 were studied to analyze rainfall thresholds of landslide in the Nepal Himalaya. Out of the 677 landslides, however, only 193 associated with rainfall data were analyzed to yield a threshold relationship between rainfall intensity, rainfall duration, and landslide initiation. The threshold relationship fitted to the lower boundary of the field defined by landslide-triggering rainfall events is I = 73.90 D-0.79 (I = rainfall intensity in mm/hr and D = duration in hours), revealed that when the daily precipitation exceeds 144 mm, the risk of landslides on Himalayan mountain slopes is high. Normalized rainfall intensity–duration relationships and landslide initiation-thresholds were also established from the data after normalizing rainfall-intensity data with respect to mean annual precipitation (MAP) as an index in which NI = 1.10 D-0.59 (NI = normalized intensity (h-1) and D = duration in hours). When various threshold curves for rainfall-triggering landslides proposed by different researcher are compared with 2004 landslide data of Shikoku, curve proposed by Larsen and Simon (1993) for Puerto Rico (humid-tropical region) and threshold lines discovered in this Ph.D. research for the Nepal Himalaya are more or less ensue the data of average rainfall intensity during failure in Shikoku due to 2004 extreme rainfall events.
In this PhD research both statistical and deterministic landslide hazard modelling was employed in the small catchments of Shikoku and the Lesser Himalaya of Nepal. For statistical modelling, the weights-of-evidence modelling and information value method were applied, within a geographical information system (GIS), to derive landslide susceptibility maps of two small catchments of Shikoku, Japan and the ideal Lesser Himalayan terrain of Nepal. The success rates were estimated to evaluate the accuracy of landslide susceptibility and hazard maps and it is found that the models are useful in landslide susceptibility and hazard mapping even in small catchment scale. The Digital Elevation Model (DEM)-based deterministic distributed analysis in GIS was carried out to calculate the probability of slope failure in an ideal terrain of the Nepal Himalaya. When normally distributed failure probability value were checked against existing landslides, it was found that more than 50% of the pixels of existing landslides coincided with a high calculated probability of failure. Although the deterministic distributed analysis has certain drawbacks, as described by previous researchers, this study concluded that the calculated failure probability could be utilized to predict the probability of slope failure in Himalayan terrain during extreme rainfall events.
Taking the reference of two rainfall thresholds relationships established in this PhD research, two models of early warning systems (RIEWS and N-RIEWS) for Nepal are also proposed. A test application of these prototype models has been also applied in four past landslide events and shows acceptable accuracy.
Lastly, the findings of regional issues of rainfall-induced landslides provided in this thesis will be very useful to reduce lost of lives and properties due to landslides in the Nepal Himalaya and Shikoku, Japan.
If you are interested to have copy of this thesis, please place your order below. The price include postal charge. You will receive a loose set of thesis (not binding form). You can make binding as per your need or suitable to your bookshelf.
1. Color copy, price US$ 149.00 only, including postal charge.
2. B/W or monochrome copy, price US$ 82.00 only, including postal charge.
