Soil frequency assessment in the eroded cliffs of Mendoza River terraces, Argentina: Implications for the landslide hazard and urban planning

This paper provides an in-depth examination of the natural soil frequencies in cliffs on the northern and southern terraces of the Mendoza River in Mendoza province, Argentina (32°S), where slope instability events have been recorded. However, in the last five years, there has been a booming and worrying trend of unregulated urbanization, with buildings being constructed just a few meters from the cliff edges. This critical situation increases the area's vulnerability to slope instability. The cliffs are potentially unstable due to low-intensity earthquakes and soil saturation. The study passively monitor the terrane by soil frequencies to delineate safe or stable zones, thus reducing exposure and the consequent risk of landsliding. We used the H/V spectral ratio method to determine the dominant soil frequencies. We did this by measuring ambient vibrations using digital accelerometers. The results were interpreted in the context of the geological characterization of the eroded cliffs along the Mendoza River terraces. Additionally, the directional variation of the frequencies was analyzed. The findings reveal frequency anomalies indicating landslide hazards in areas close to cliffs where previous collapses and landslides have been recorded. These results demonstrate the significant hazard associated with slope instability, supporting the adoption of regulatory and preventive measures in land use planning for the study area.