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Topic 2 - Propagation of Debris Flows

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Topic 2 - Propagation of Debris Flows
The basal incorporation of material, also called entrainment, is a common characteristic of debris flow dynamics. The volume of a debris flow can considerably increase when compared to the initial volume, due to the erosion of material produced along the travel path. This study is a preliminary attempt to establish a simple geomorphologic approach for the calculation of volume to be entrained in a torrent, if a granular debrisflow event would occur. The methodology presented has been developed using data o
Topic 2 - Propagation of Debris Flows
Recently, Berzi & Jenkins (2008a, b) proposed a simple theory based on a linear rheology for the particle interactions, turbulent shearing of the fluid, buoyancy, and drag. They provided a complete analytical description of the steady, uniform flow of a granularfluid mixture over either an erodible or a rigid bed contained between frictional sidewalls. They also used the theory to solve for the propagation of a granular-fluid wave moving at constant velocity over a rigid bed. Here, we extend this theory to
Topic 2 - Propagation of Debris Flows
To better understand controls on debris-flow entrainment and travel distance, we examined topographic and drainage network characteristics of initiation locations in two separate debris-flow prone areas located 700 km apart along the west coast of the U.S. One area was located in northern California, the other in southern Oregon. In both areas, debris flows mobilized from slides during large storms, but, when stratified by number of contributing initiation locations, median debris-flow travel distances in O
Topic 2 - Propagation of Debris Flows
Debris Flows in nature, for example at Jiangjia Ravine, were often observed moving in the form of intermittent surges which is considered as a kind of wave that is termed as roll wave in this paper. Spatial and temporal characteristics of the roll waves at Jiangjia, as well as their separation and superposition were described in details. First-arrived waves were observed to smooth rough bed at the gentle middle reach and produce a residual layer on which a sequent wave can move with steady profile and high
Topic 2 - Propagation of Debris Flows
We replicate the propagation of the Val Rossiga debris flow (November 2002, Central Italian Alps), a 90,000 m3 event triggered by a rapid retrogressive landslide with high water content. The rheological model combines in a linear sum the viscoplastic terms of the Bingham model and a quadratic inertial term. The model requires as input data the bulked hydrograph and the empirical coefficients which describe the exponential dependence of the rheological parameters (i.e. Bingham viscosity and yield stress) on
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