Study of the spatial distribution and the temporal trend of landslide disasters that occurred in the Nepal Himalayas from 2011 to 2020

Landslide disasters in Nepal are widely reported to have increased in the last decade, but there has been limited on trends in landslide occurrence in Nepal from 2011 to 2020. This study presents the spatio-temporal distribution and trends of landslide disasters in the Nepal Himalayas and identifies landslide-prone areas. Landslide disaster data was collected to assess annual variations, investigate the relation between rainfall and landslides, describe the landslide distribution pattern, conduct statistical analysis, and predict landslide causes and triggering factors. The dataset suggests that the overall trend in landslide disasters in Nepal from 2011 to 2020 is increasing, with a high level of variability in the number of landslide disasters from year to year, depending on several factors. Results show that landslide events were clustered in space and time, with 93.26% of total landslides occurring in the rainy season. The average density of landslide disasters in 2011 was 0.85 events per 1000 km 2 and increased to 3.34 in 2020. The effect of earthquake preconditioning was observed as the landslide disaster rate has been elevated since the 2015 Gorkha earthquake with systematic shifting of locations over time. Power-law relationships fit well for the cumulative frequency distribution of daily landslide disasters and the probability density of time interval between landslides. The gap between landslide events was observed as 1–170 days. Moreover, trend analysis has shown an increasing trend of landslide disasters both seasonally and annually.