An integrated approach to map landslides in Chittagong Hilly Areas, Bangladesh, using Google Earth and field mapping

Abstract

This paper presents a landslide inventory map for the Chittagong Hilly Areas of Bangladesh based on Google Earth and field mapping. We developed a set of criteria to identify landslides in Google Earth and introduced a method to assess the accuracy of mapped landslides when they are recorded as points rather than polygons in the field. In total, 230 landslides (mainly occurred between 2001 and 2016) were mapped in Google Earth. Field mapping identified 548 landslides and most of them occurred during Summer 2017. In total, the inventory includes 730 landslides for Chittagong Hilly Areas from 2001 to 2017. The field validation suggests that the accuracy of mapped landslides using Google Earth varies from 69 to 88%. Field work is preferred to map detailed landslides in or near urban areas, road networks, human settlements, and other accessible areas, while Google Earth has the advantage to map landslides in inaccessible areas. The combination of these two approaches provides a means to prepare the landslide inventory for an entire area.