[H-DS07] 地すべりおよび関連現象

[HDS07-16] Relations between the macroscopic dynamics of granular flows and the generated seismic signals: Insights from laboratory flume experiments

*Wei Li¹、Dongpo Wang²、Issei Doi³、Gonghui Wang³ (1.School of Highway, Chang’an University, Xi’an, China、2.State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu, China、3.Disaster Prevention Research Institute, Kyoto University, Uji, Japan)

キーワード：granular flows, seismic signals, flow dynamics, basal forces, rheological properties

Seismic signals produced by geophysical flows such as landslides can be captured by seismic monitoring systems. By thoroughly examining these signals, we can gain valuable insights into the dynamic behavior and properties of natural flows. However, achieving this requires establishing clear and quantitative relations between the characteristics of the flow and the features of the generated seismic signals. Here, a series of laboratory flume experiments with varying flow masses and particle sizes were to investigate the granular flow dynamics and its seismic signatures, and the relationship between them was discussed. Our results show that as the flow moves downstream, it becomes thinner and faster. The flow mass has a significant influence on the mean basal forces, while the particle size plays a more critical role in the generation of basal force fluctuations, and the mean forces and the fluctuating forces are significantly positively correlated. Basal force fluctuations and seismic signals are strongly nonlinearly related to the bulk flow properties such as flow velocity, height, density, indicating that thicker, denser and faster flows generate stronger basal force fluctuations and more intense seismic signals. However, particle size significantly influences this relationship. We also demonstrate that the inertial number, characterizing the rheological properties of granular flows, can unify basal force fluctuations and seismic signals across different particle sizes, exhibiting a negative correlation on the temporal scale. This may imply that the macroscopic rheological descriptions can be leveraged into the development of seismic signal models.