Landslide exposure analysis by utilizing big geodata in Bogor area, West Java Province of Indonesia

Landslide exposure is an adept approach to measuring the consequences of a landslide hazard on elements at risk. Landslides in the Bogor area, Province of West Java, Indonesia, have increased in number and consequences since 2015. The Bogor area also has a fairly large population that may aggravate the impact. Accordingly, this study aims to measure the landslide exposures over two substantial elements (i.e., population and land use). The actual resources for these exposed elements are available from the open-access geodata and the Google Earth Engine (GEE) platform. For the land use classification, this study employs two robust machine-learning (ML) algorithms on a GEE-based Object-based Image Analysis (OBIA), i.e., Random Forest (RF) and Gradient Tree Boosting (GTB). Moreover, the population data were retrieved from WorldPop estimates. Landslide exposures were then analyzed through an overlay between these two elements with a landslide hazard map sourced from the former study. The results show that in 2020, the Bogor area had an exposed population of 885,353 people, with Bogor Selatan District having the highest exposed population (135,475 people). Moreover, in 2021, the Bogor area had a total exposed land use reaching 347.9 km2, with built-up area having the most extensive, reaching 45.9% of the total exposed area. Here, Sukajaya District had the largest exposed land use (39.1 km2). This study is expected to reach multifaceted entities that contribute to strengthening landslide risk reduction. Through this spatial awareness of the highly exposed areas to landslides, mitigation measures can be taken accordingly.