Fan-Surface Evidence for Debris-Flow Avulsion Controls and Probabilities, Saline Valley, California

摘要: Debris‐flow fans form by shifts of the active channel, termed avulsions. Field and experimental evidence suggest that debris‐flow avulsions may be induced depositional lobes locally plug a channel or super‐elevation bed above surrounding fan surface, analogy to fluvial fans. To understand avulsion processes, we differentiate between these controls quantifying spatial distribution lobe dimensions, along with channel‐bed super‐elevation, on nine in Saline Valley, California, USA. Channel beds are generally super‐elevated 2‐5 depths more than 7 depths, thereby substantially exceeding Depositional‐lobe thickness depth decrease distance from apex, although both highly variable across Median roughly correspond 50‐75th percentiles thicknesses, while minimum 10‐25th percentiles. In contrast, thicknesses have triggered equal local average twice as thick median thickness. The correspondence locations deposits, lack correlation leads us infer mostly caused forming plugs. Although results vary climatic tectonic setting, our findings indicate hazard assessment populated should include mapping monitoring relative typical deposit given fan.