A SPH depth integrated model for Popocatépetl 2001 lahar (Mexico): Sensitivity analysis and runout simulation

Abstract

Lahars are debris flows of volcanic origin, which can endanger or even destroy communities located near the flanks of volcanoes. Lahars are not always triggered by eruptions; they can form during heavy rainfall or after hydrothermal alteration and volcanic edifice collapse. Decision makers need lahar hazard maps to devise hazard prevention measures that will prevent casualties, so lahar modelling is an important tool for assessing flow behavior and determining inundation areas. The depth integrated numerical model used in this study is derived from the velocity–pressure of the Biot–Zienkiewicz model and was discretized using the smoothed particle hydrodynamics (SPH) method to simulate a lahar that occurred at Popocatépetl volcano in 2001. In order to investigate the convergence of the model, we used a range of different SPH mesh resolutions. Once the optimum mesh resolution was bounded, we analyzed the model's sensitivity to the initial lahar volume, the density of the geomaterial, and the rheological parameter of the Bingham fluid. The results show that the SPH depth integrated model produced a highly accurate simulation of the distribution and velocity of the 2001 lahar. The study also shows the effects of SPH mesh resolution and the relevant influence of rheological parameters.