Effects of mass entrainment on the estimation of landslide parameters from long-period seismic inversion

Force history inverted from long-period seismic records for a landslide has been widely used to extract its physical parameters. Most previous studies have adopted the point-source constant-mass landslide model during the inversion. In this study, we quantitatively investigate the effects of mass entrainment at different locations along the sliding path during the interpretation of inversion results. To demonstrate our analysis, we carried out the long-period seismic waveform inversion for the 2003 Qianjiangping landslide to obtain its force history and subsequently estimated its movement parameters. We propose a mass entrainment model based on the conservation of kinetic energy. The predictions of our mass entrainment model are verified using the inversion results of the Qianjiangping landslide and other events. Results from our mass entrainment model suggest that when half of the sliding mass is entrained at different locations along the sliding path, the estimated masses and maximum velocities vary between 50-100% and 83.38-122.26%, respectively. In particular, when the entrainment occurred at the slow-down phase, the estimated mass is less than 60% of the total mass, which is a good approximation of the initial sliding mass. The model can provide useful constraints for quantitative interpretations of landslide force history inversions of landslides.