The Role of Water and Weathering Processes in Landslides in Hungarian Loess Sediments

Abstract

Loess-paleosol bluffs can be unstable, but in the course of urbanization, houses may be built in such locations to take advantage of the view. One factor affecting the stability of such bluffs is water, the role of which in mass movements is well established. In this study, the connection of mass movements to meteorological conditions, such as rainfall and subsequent water level changes, was researched using new statistical methods. The periodicity of the water level of the Danube was analyzed using wavelet spectrum analyses, while changepoint analysis was used to determine variations in the quantity of precipitation. These results were compared to the chronology of six mass movements in Kulcs, Hungary. This study also focused on the changes in geochemical properties of loess in different weather conditions (dry periods, wet periods, and flooding). The results showed that only two mass movements were connected to hydrological conditions, and in the other case human activity and geochemical changes may have been factors. The results of geochemical models created using PHREEQC showed calcite and kaolinite precipitation, and albite and dolomite dissolution as the main mineral changes over the course of a year. Albite was found to dissolve only in wet periods, and kaolinite precipitation was significant during flood periods.