Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Identifying post-earthquake debris flow hazard using Massflow
Abstract Catastrophic debris flows are common after large earthquakes and pose a significant risk for recovering communities. The depositional volume of these large debris flows is often much greater than the initiation volume, suggesting that bulking of the flow plays an important role in determining their volume, speed, and runout distance. Observations from recent earthquakes have driven progress in understanding the relationship between triggering rainfall events and the timing of post-earthquake debris flows. However, we lack an adequate mechanism for quantifying bulking and applying it within a hazard context. Here we apply a 2D dynamic debris flow model (Massflow) that incorporates a process-based expression of basal entrainment to understand how debris flow bulking may occur within post-earthquake catchments and develop hazard maps. Focussing on catchments in the epicentral area of the 2008 Mw 7.9 Wenchuan Earthquake, we first parameterised the model based on a large debris flow that occurred within the Hongchun catchment, before applying the calibrated model to adjoining catchments. A model sensitivity analysis identified three main controls on debris flow bulking; the saturation level of entrainable material along the flow pathway, and the size and position of initial mass failures. The model demonstrates that the difference between small and very large debris flows occur across a narrow range of pore-water ratios (λ). Below λ = 0.65 flows falter at the base of hillslopes and come to rest in the valley bottom, above λ = 0.70 they build sufficient mass and momentum to sustain channelised flow and transport large volumes of material beyond the valley confines. Finally, we applied the model across different catchments to develop hazard maps that demonstrate the utility of Massflow in post-earthquake planning within the Wenchuan epicentral region.
Highlights Focussing on the Wenchuan region in China, we apply a 2D dynamic debris flow model (Massflow) We use Massflow's process-based expression of basal entrainment to examine debris flow bulking We find a narrow range of pore-water ratios (λ) mark the difference between small and large debris flows Finally, we applied the model across different catchments to develop hazard maps
Identifying post-earthquake debris flow hazard using Massflow
Abstract Catastrophic debris flows are common after large earthquakes and pose a significant risk for recovering communities. The depositional volume of these large debris flows is often much greater than the initiation volume, suggesting that bulking of the flow plays an important role in determining their volume, speed, and runout distance. Observations from recent earthquakes have driven progress in understanding the relationship between triggering rainfall events and the timing of post-earthquake debris flows. However, we lack an adequate mechanism for quantifying bulking and applying it within a hazard context. Here we apply a 2D dynamic debris flow model (Massflow) that incorporates a process-based expression of basal entrainment to understand how debris flow bulking may occur within post-earthquake catchments and develop hazard maps. Focussing on catchments in the epicentral area of the 2008 Mw 7.9 Wenchuan Earthquake, we first parameterised the model based on a large debris flow that occurred within the Hongchun catchment, before applying the calibrated model to adjoining catchments. A model sensitivity analysis identified three main controls on debris flow bulking; the saturation level of entrainable material along the flow pathway, and the size and position of initial mass failures. The model demonstrates that the difference between small and very large debris flows occur across a narrow range of pore-water ratios (λ). Below λ = 0.65 flows falter at the base of hillslopes and come to rest in the valley bottom, above λ = 0.70 they build sufficient mass and momentum to sustain channelised flow and transport large volumes of material beyond the valley confines. Finally, we applied the model across different catchments to develop hazard maps that demonstrate the utility of Massflow in post-earthquake planning within the Wenchuan epicentral region.
Highlights Focussing on the Wenchuan region in China, we apply a 2D dynamic debris flow model (Massflow) We use Massflow's process-based expression of basal entrainment to examine debris flow bulking We find a narrow range of pore-water ratios (λ) mark the difference between small and large debris flows Finally, we applied the model across different catchments to develop hazard maps
Identifying post-earthquake debris flow hazard using Massflow
Horton, Alexander J. (Autor:in) / Hales, Tristram C. (Autor:in) / Ouyang, Chaojun (Autor:in) / Fan, Xuanmei (Autor:in)
Engineering Geology ; 258
09.05.2019
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
Engineering measures for debris flow hazard mitigation in the Wenchuan earthquake area
| Online Contents | 2014
Mapping Debris-Flow Hazard in Honolulu Using a DEM
| British Library Conference Proceedings | 1993
Hazard Assessment of Debris Flow: A Case Study of the Huiyazi Debris Flow
| DOAJ | 2024