2021/01/11 by Vincent Bachelet, A. Mangeney, Bachelet, Vincent +10
Earth and Planetary Sciences · Engineering · Environmental Science · Physics and Astronomy · #FOS: Physical sciences #Granular flow and fluidized beds #Landslides and related hazards #Seismic Waves and Analysis #Soft Condensed Matter (cond-mat.soft) #cond-mat.soft
paper · pdf · doi:10.48550/arxiv.2101.04161
Preprint, submitted to Journal of Geophysical Research - Earth Surface. 51 pages, 18 figures
arxiv created 2021/01/11 · openalex publication_date 2021/01/11 · arxiv updated 2021/01/13 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The seismic waves emitted during granular flows are generated by different sources: high frequencies by inter-particle shocks and low frequencies by global motion and large scale deformation. To unravel these different mechanisms, an experimental study has been performed on the seismic waves emitted by dry quasi steady granular flows. The emitted seismic waves were recorded using shock accelerometers and the flow dynamics were captured with a fast camera. The mechanical characteristics of the particle shocks were analyzed, along with the duration between shocks and the correlations in the particle motion. The high-frequency seismic waves (1-50 kHz) were found to originate from particle shocks and waves trapped in the flowing layer. The low-frequency waves (20-60 Hz) were generated by the oscillations of the particles along their trajectories, i.e. from cycles of dilation/compression during the shear. The profiles of granular temperature (i.e. the square of particle velocity fluctuations) and average velocity were measured and related to the average properties of the flow as well as to the slope angle and flow thickness. These profiles were then used in a simple steady granular flow model to predict the radiated seismic energy and the energetic efficiency, i.e. the fraction of the flow potential energy converted to seismic energy. Scaling laws relating the seismic power, the shear strain rate and the inertial number were derived. In particular, the emitted seismic power is proportional to the granular temperature, which is also related to the mean flow velocity.