17:15 〜 19:15
[MIS01-P02] Flow Transformation in Submarine Sediment Gravity Flows: Experimental Analysis Using a Flume System
キーワード：混濁流、土石流
Submarine sediment gravity flows, such as debris flows and turbidity currents, play a crucial role in deep-sea sediment transport and reservoir formation. In recent years, it has become clear that these two types of flow transform into each other in response to changes in concentration and clay content. This flow transformation could explain the characteristics of changes in the shape and grain size of sandy deposits on the deep seafloor. Therefore, this study aims to reproduce and analyze the transformation mechanisms between debris flows and turbidity currents through flume experiments. This study conducted experiments to clarify under what conditions this flow transformation occurs and how the characteristics of the resulting sediment change. In the experiments, the velocity distribution of the flow is measured using Particle Image Velocimetry (PIV) of the videos taken by the high-speed camera, while sediment samples are collected and analyzed using Scanning Electron Microscopy (SEM) to examine the spatial distribution of clay content. The results of the PIV analysis clearly exhibited the areas that behave as laminar flow and turbulent flow within the flow. These areas correspond to where debris flows and turbidity currents are flowing. Furthermore, we observed rapid changes in sediment textures and geometry, with clay content variation as a result of flow transformation. Understanding these changes is useful for reconstructing the flow process from actual deposits, and for inferring the geometry and physical properties of strata in previously unobserved areas. This relationship is expected to provide insights into potential reservoir distribution.