The tendency of occurrences of slope failures in future in an area is landslides susceptibility. This tendency in eastern hills of Rara Lake was analyzed through mapping process. Bivariate statistical index method was used to produce the susceptibility of landslides. Ninety six slope failures were delineated from Google Earth imagery. The ratio of landslide densities of each individual factor classes to that of whole area gave weight values necessary to produce landslide susceptibility index (LSI). East and South facing slopes, gradients of <30o, elevation of 2000-2800 m, buffers closer to road and streams, grassland and cultivation lands, and lithology of pelitic metamorphic rocks were factor classes with positive weight values. The LSI values ranging from -7.12 to 5.45 were reclassified into five susceptibility classes. Landslide densities of 8.12 and 4.76 per km2 were observed for very high and high susceptible zones. Success rate curve, made from 35 landslides located in the field survey, showed 0.76 portion area under the curve. This gives 76% overall success rate. Higher susceptible areas are cultivated areas and grasslands, where most houses were located. Thus, knowing the landslide susceptibility of areas, necessary preparedness can be done to reduce the impacts.

Abstract. Locating landslides and determining its extent is deemed an important task in estimating loss and damage and carry out mitigation works. As landslides are recurring phenomena in the research site, Siwalik Hills of western Nepal, freely available Sentinel-2 satellite images were considered to delineate landslides. The method employed in this process was Object-Based Image Analysis carried out in eCognition software using multiresolution segmentation algorithm. Parameters taken for segmentation were a scale of 20, the shape of 0.3, and compactness of 0.5. When a threshold value of < 0.35 in NDVI was used to distinguish landslides from image objects, some non-landslide objects were also selected. These false positives were removed successively using the threshold values on different bands, band ratios, slope information, hillshade and geometrical properties of image objects. There were altogether 264 landslides detected in the study area with size ranging from 300 m2 to 1675 m2 and landslide density of approximately 2 per km2. The accuracy, when compared to reference inventory, showed correctness and completeness measuring 80.28% and 66.27% respectively. These results showed semi-automatic landslide extraction was successful and Sentinel-2 can be used for similar tasks in other areas of Siwalik.

The occurrence of landslides in mountainous areas of Nepal is recurrent phenomena and this can be disastrous if occurred within human settlements. Proper research is required to manage and reduce the risks of the disaster in places where landslides had occurred frequently. In risk assessment estimation of vulnerability is one major component. This research was aimed to generate information on the vulnerability of people in the Panchase area of central Nepal. The method of analytical hierarchy process was used to define the weightage to be assigned for 4 factors and 26 indicators used in the research. 377 households were surveyed with a questionnaire designed to collect information on those indicators. The households sampled for the survey were made sure that they were near or around the landslide affected area. The response for each indicator was converted into scores which when summed up yielded the vulnerability score. This score for each household was used to categorize households into five levels of vulnerability from very low, low, moderate, high, to very high. The numbers of households in each category were 16, 92, 191, 75, and 3 respectively. Environmental and economic indicators were inflicting higher vulnerability in this research location. Remoteness and lesser number of facilities and/or services, lower numbers of governmental offices, absence of banking and financial institutions, lesser preferences for insurances and savings, degraded natural water sources were major determinants of higher vulnerability in Panchase. These indicators should be prioritized during disaster risk management in Panchase.

The dense settlements at the eastern hills of Rara Lake are at higher risk of existing landslides. Seepage of water from the lake has increased erosion rates, exaggerating the threats to villages. People are worried due to the potential of inadvertent disaster, therefore it became necessary to estimate the vulnerability of the communities and inform concerned authorities. Setting this requirement as an objective, underlying influencing indicators were assessed. The vulnerability assessment was based on the scoring of the responses emanated from indicator-based household's survey. These scores were summed up to generate indices and also mapped with their true locations. Vulnerability scores ranged from 16.50 to 21.75 and were categorized into five classes after standardization. A moderate vulnerability was exhibited by 33.08% of households sampled. High and very high categories of vulnerability occupied 18.80% and 4.51% of households, respectively. Field observation showed solitary households built away from village clusters were highly vulnerable. Most households showed moderate vulnerability and characteristics like stones/mud-built houses, firewood as a primary fuel, decreasing forests and grasslands, increasing temperatures, and decreasing rainfall were major influencing indicators for higher vulnerability in the research area.

No abstract