Integrated geochemical, geoelectrical, and UAV-based methods for analyzing the Güzelyalı landslide (Çanakkale, Türkiye)

The number of reactivations increased in the Güzelyalı-Erenköy landslide area after 2013 in Çanakkale, Türkiye, where historical landslide activity has been recorded since 1875. This area is home to numerous summer residences and experiences ongoing slow-moving landslide activity along a 400-m-long slope, extending from the heavily trafficked Çanakkale-İzmir highway to the coastline. In this study, the nature of the reactivations was evaluated by considering the conditioning and triggering factors that contributed to the landslide. The evaluation was based on geochemical analyses, field observations, geoelectric measurements, and unmanned aerial vehicle (UAV) data. The results revealed that the sliding occurred along a moist slip surface, rich in various clay minerals such as illite, montmorillonite, and vermiculite, at a depth of approximately 4.5 m, as determined by ERT (Electrical Resistivity Tomography). Vertical movements within the landslide area, including rises and subsidences, accounted for changes of up to 0.1 m between 2013 and 2023. Chemical Index of Weathering (CIW), Chemical Index of Alteration (CIA), and Plagioclase Index of Alteration (PIA) calculations obtained from the X-ray fluorescence (XRF) spectroscopy analysis indicate that the sliding surface is subjected to strong weathering, and these values are compatible with the X-Ray diffraction (XRD) data.