A Slippery Slope: Evaluating the Causal Factors of the Mramor Landslide (Southern Serbia)

Abstract

This research aims to depict the characteristics and causal factors influencing the Mramor creep landslide, typically found in Neogene formations in southern Serbia, especially along the left bank of the South Morava River. Given that this particular landslide has been active for more than 70 years and covers an area of approximately 1 km², it directly impacts the lives of inhabitants in the settlement of Mramor, which is part of the broader area of the city of Niš. Additionally, it affects surrounding infrastructure. Our investigation is focused on the main causal factors, recognizing that continuous landslide events involve complex components, including climatological characteristics, properties of the geological substrate, and human activities that have contributed to significant landscape changes and the acceleration of terrain instability. For this analysis, daily precipitation and air temperature datasets from the European Climate Assessment and Dataset (ECA&D) for the Niš meteorological station for the period 1950-2019 were used. Selected meteorological parameters were employed to calculate rainfall erosivity indices (indicators of soil loss risk) such as the Precipitation Concentration Index (PCI), Modified Fournier Index (MFI), Rainfall Erosivity (RE), and Erosivity Density (ED) over the investigated period. Additionally, the Standardized Precipitation Index (SPI) and Lang aridity index (AILang) were obtained to evaluate the relation of air temperature, precipitation, and possible groundwater conditions and their influence on landslide dynamics. The Mann–Kendall (MK) trend test was applied to identify potential rising and/or declining trends in both meteorological parameters and calculated indices. Online news reports of pluvial flooding and landslide occurrences were used to quality assures daily rainfall outliers and compares extreme precipitation events (exceeded rainfall erosivity thresholds) with pluvial aggressivity/climate change indices/indicators. This was achieved by examining online news reports and academic literature during the period 2000-2019 using research-related keywords. To examine the relationship between the obtained index values and the potential rainfall erosivity causal climate driver, the North Atlantic Oscillation (NAO), Pearson (r) and Spearman correlation (ρ) with confidence levels of 0.1, 0.01, and 0.05 were utilized. The authors also implemented advanced numerical, Geographic Information Systems (GIS), modified Analytic Hierarchy Process (M–AHP), and remote-sensing techniques to monitor and assess temporal changes in topographical features and landslide events at the local level. It can be noted that the Mramor landslide serves as a compelling case study for examining the intricate interplay between geological processes, environmental factors, and human activities in landslide-prone areas in southern Serbia. The initial results from the research offer insight into the broader implications of the Mramor landslide and underscore the significance of ongoing research and monitoring in the field of hydro-meteorological hazards and risk management. In this way, the obtained results related to the interplay of causal landslide factors can inform future strategies for disaster preparedness and sustainable land management in the region, with implications for mitigation strategies at local to regional scales.