The Influence of the DSM Spatial Resolution in Rockfall Simulation and Validation with In Situ Data

Abstract

Remote sensing constitutes an advantageous tool towards the landslide/rockfall susceptibility mapping by incorporating optical satellite or radar data and photogrammetric data in Geographical Information System environment. A plethora of rockfall data can be derived by gigital surface models (DSMs). This article focuses on the effect of the spatial resolution of DSMs in rockfall investigations solely. DSMs with pixel size ranging from 5 cm to 90 m were taken into account for the study of three different rockfall events occurring in Western Greece, namely, at Moira, Myloi and Platiana settlements. Elevation profiles along the rockfall bodies were created from the diverse DSMs in GIS environment. Then, these profiles were implemented into the RocFall software for 2D rockfall simulations. The produced simulations were evaluated against their spatial resolution of DSMs and were confirmed with field observations and measurements. The ultimate scope of this paper is to conclude to the most appropriate DSM for rockfall simulations via RocFall software. It is observed that DSMs with high spatial resolution depicted a detailed and realistic topography, while DSMs with coarse/low resolution flattened the surface roughness. As rockfall simulations are linked to slope profile, this observation has an impact on RocFall outcomes. According to this study the most appropriate DSM, pertaining to this type of research, is the UAV, which produces the more accurate and realistic results. These results were assessed through the use of in situ measurements taken by the real rockfall events.