Robustness Evaluation of the Probability-Based Htca Model for Simulating Debris Flow Run-Out Extent : A Case Study of the 2010 Hongchun Event in China

Probability-based cellular automaton (CA) models are a kind of alternative useful tool for simulating debris flow run-out extent by teams’ efforts in the past years. Despite previous studies have indicated that CA models perform well in debris flow run-out extent modeling with high efficiency, research consistently shows that the simulating results are sensitive to some key parameters, the impact of which remains unclear. The knowledge of this aspect is fundamental for evaluating the model’s robustness. In this paper, the up-to-date improvement, i.e., the so-called hydrodynamic and topography-based cellular automaton (HTCA) model, is introduced. The basic of the model is briefly reviewed, and two key input parameters including steps of Monte-Carlo Iteration (MCI) and spatial resolution of digital terrain model (DTM) data, are recognized and tested. Various practical scenarios regarding the effect of bed-sediment entrainment and check dam are further considered to assess the capability of the HTCA model. To show the impact of both key parameters and specific scenarios, the August 14, 2010, post-seismic debris-flow event in Hongchun gully at the eastern Wenchuan area in China, is selected as a case study. Results illustrate the strong robustness of the model to deal with specific scenarios. Sensitivity analysis further suggests that the MCI value should be determined according to the resolution of the input DTM data, thereby robustness in the HTCA model can be improved