Threatening dynamics of landslide disaster risk in Himalaya region due to adverse climatic and anthropogenic changes: geospatial approach

Geoenvironmentally the eastern part of the Himalaya region is highly vulnerable to landslide and other natural disasters as it consists of fragmented and tectonically active geology and geomorphology, very high monsoon rainfall and subsequent runoff, rugged hilly terrain with high ranges of elevation and slope, dense drainage density etc. Other hand, the unplanned developmental activities keep going and scaling up this vulnerability and risk to landslide associated disasters. Addressing this burning issue, a geospatial technology-based case study of the Kohima district, Nagaland state (India), is presented here. Results reveal that the region is under a high rate of monsoon climate change (increasing temperature, rainfall, rainy days, rainfall events and flood events with an annual rate of 0.35%, 1.12%, 0.36%, 2.67% and 4% respectively), land use degradation (increasing built-up area, agricultural land and wasteland with 0.28%, 0.27% and 0.05% annual rate respectively, decreasing forest, shrubs and water bodies with 0.60%, 0.01% and 0.01% annual rates respectively) and demographic changes (increasing urban as well and rural population density with 0.53–2.10% and 0.55–2.14% respectively). Accumulated impacts of climate change, land use degradation and demographic changes causing an increase in socioeconomic vulnerability and risk to landslide disaster. landslide hazard zones and vulnerability zones extending with 0.77% (7.51 km2) and 0.84% (8.16 km2) annual rates respectively, subsequently the landslide risk zones categorized as a moderate, high and very high potential risk, have been spreading out with a yearly rate of 0.07% (0.65 km2), 0.13% (1.31 km2) and 0.03% (0.33 km2) respectively. It decreases the area under low and very low-risk zones by 0.17% (1.63 km2) and 0.07% (0.65 km2) annual rates respectively. Following up on these annual rates, the spatial distribution of landslide hazard, vulnerability and risk zones for the next decade (2031–2040) have also been projected, revealing alarming situations, if landslide disaster risk reduction (LDRR) measures were not implemented in timely. It is strongly believed that the proposed study will be very useful for district-level planners and administrators to implement sustainable development planning, for the scientific fraternity to enhance their research work in the field of landslide disaster management and for individuals to save their life and property.