Fast estimation of landslide blocks’ volume from seismic noise measurements

Rock mass volume estimation is crucial for assessing landslide hazard, but it is often challenging. Seismic ambient noise data and polarisation analysis can be used to identify the eigenfrequencies of the blocks, which are in turn related to their volume. The aim of this work is to propose a procedure to build an eigenfrequency-volume abacus to estimate the order of magnitude of blocks’ volumes from the extracted resonance frequencies independently estimating the blocks’ area. The resonance frequency is extracted from seismic noise measurements analysed using the Horizontal-to-Vertical Spectral Ratio technique. The abacus is developed here by means of numerical simulations and field data, acquired over lateral spreads and block slides on Malta Island, where independent direct estimates of the blocks’ volume are available. These were used to validate the proposed methodology in two test sites. The volume of landslide rock blocks can be estimated from seismic noise measurements identifying their vibration signal, knowing the blocks’ area, and using an adequate abacus.