A novel approach to measuring pore fluid sediment concentrations of debris flows in a volcanic torrent

Pore fluid in a debris flow is not fully understood, despite its contribution to the fluidity of flow. To observe sediment concentrations pore fluids flows, we established novel monitoring system volcanic catchment, southern Japan. An observation culvert, 1.0 m width, 1.5 height and 2.0 length, was placed along stream bank. intake covered by grating equipped on side culvert so that only flows led inside. Measurements dielectric permittivities were conducted within used for calculation fluid. The successfully measured natural flows. preliminary revealed volumetric concentration varied from approximately 5 69 %, which slightly smaller or similar those entire Successive occurrences caused decreases with each surge.