Derivation of earthquake-induced landslide distribution using aerial photogrammetry: the January 24, 2020, Elazig (Turkey) earthquake

Abstract

On January 24, 2020, an earthquake with the Mw of 6.8 occurred on the East Anatolian Fault Zone in Elazig Province, Turkey, and triggered many landslides. Even though Turkey is in a high seismic zone and has highly susceptible areas to landslides, event-based inventories of landslides triggered by earthquakes have not yet been published in the international literature. The purpose of the present study is to compile the landslide inventory triggered by the Elazig earthquake. A novel approach involved change detection analyses was applied by using high-resolution 3D digital surface models (DSMs) obtained from pre- and post-earthquake aerial photos. In the study, a total of 328 landslides sized between 133 m2 and 3 × 106 m2 were mapped by visual interpretations. The rollover effect and fractal dimension of the failures were obtained as 3600 m2 and –1.48, respectively. The total landslide area including new active zones developed after 2018 within the existing mass was calculated as approximately 8 × 106 m2. According to the volumetric change analyses, the displacements were between –17.66 m and 14.11 m. It is evident that using photogrammetric methods to produce very high-resolution DSMs enables precise determination of landslide activity after an earthquake and increases the quality of the inventory. Consequently, application of the surface comparison methods immediately after large earthquakes provides great benefits in obtaining new landslide data open up important possibilities for a better understanding of the mechanism of landslides triggered by earthquakes, thus minimizing losses sourced from them.