On the use of seismic noise studies for landslide rock block hazard assessment

As emphasized by Pazzi et al. 1 , robust constraints on rock-mass volume are essential for landslide hazard assessment. However, such estimates are inherently challenging due to (i) complex geometries, (ii) heterogeneous material properties, and (iii) poorly constrained boundary conditions, particularly at depth. To address this, Pazzi et al. 1 propose estimating rock-block volumes—at least their order of magnitude—from their fundamental eigenfrequency ( f 0 ) in a lateral spread and block-slide setting on Malta Island. Each block’s fundamental frequency is obtained from the peak of the Horizontal-to-Vertical Spectral Ratio (HVSR) curve ( f H V ), and the volume is inferred using an abacus derived from numerical simulations of base-embedded, parallelepiped blocks, assuming that the cross-sectional area is independently constrained.