Monitoring the Preonzo Rock Slope Instability Using Resonance Mode Analysis

Reliable monitoring of unstable rock slopes is a prerequisite for successful mitigation landslide hazards. However, most state-of-the art techniques rely on measuring the local surface displacement in potential release area. In contrast, recording ambient vibration data allows analyzing structural dynamic parameters slope, such as resonance frequency, polarization vibration, and energy dissipation. These can be linked to properties instability, example, stiffness fracture network orientation. We developed processing method continuous seismic based enhanced frequency domain decomposition modal analysis applied it slope Preonzo Switzerland (∼140,000 m3). Four years recorded at two permanent seismometers instability were analyzed, providing damping ratio, normal mode shapes fundamental (∼3.5 Hz) first higher (∼4.2 vibrational mode. found that reliably used monitor response an slope. observed annual changes all with ratio varying between 6.0% 9.7% The appear primarily driven by temperature only secondarily opening closing fractures. No large failure was registered during observation period. provide baseline model ongoing recognize before future collapse. setup proposed builds complementary system displacement-based surveying.