Digital Landslide Risk Mapping and Landslide Database for Bhutan Through Mobile App for Bhutan

Bhutan experiences frequent landslides during the monsoon season. Although there are a few studies, they do not cover the entire country. Additionally, these maps are published in hard copy, making them less accessible for reference. There is also no comprehensive landslide database in Bhutan. Thus, the purpose of the study is to develop a digital landslide risk map of Bhutan and create a database through a mobile app known as Bhutan Landslide Information (BLI). The landslide map was produced using twelve influencing factors and a landslide inventory collected through field visits and from relevant offices. A total of 2,324 landslide locations were documented, with 70% (1,620) used for training and 30% (704) for testing. The analysis was conducted using logistic regression. Tolerance (TOL) and Variance Inflation Factor (VIF) were used to diagnose redundant factors. Analysis showed all factors had a VIF less than 5 and tolerance above 0.1, indicating none of the independent factors were redundant. According to the logistic regression model, Land Use Land Cover (LULC) had the highest coefficient of 0.8027, making it the most influential factor for landslide events. Accuracy and Area Under the Curve (AUC) validate generated landslide risk map. The values of accuracy and AUC are 0.8852 and 0.9457, respectively. The landslide map was then exported to QGIS2Web to be made available online and incorporated into the BLI mobile app. Users can locate and view the landslide risk zone. Additionally, a landslide database was developed, allowing users to take photographs of landslide events through the BLI app. The app automatically records the landslide location (latitude and longitude) and the time the photograph was taken. Users can download the landslide database as a CSV file for research and decision-making purposes.