Numerical simulation of the last flank‐collapse event of Montagne Pelée, Martinique, Lesser Antilles

Abstract

We model the submarine emplacement of a debris avalanche generated by the last flank‐collapse event of Montagne Pelée volcano. We estimate the collapsed volume (1.7 km3) using both the volume of the missing material in the horseshoe‐shaped structure and the volume of submarine deposits. This avalanche is treated as the gravitational flow of a homogeneous continuum. It is simulated by a finite‐difference model, solving mass and momentum conservation equations, that are depth‐averaged over the slide thickness. Numerical simulations show that the emplacement of this debris‐avalanche can be suitably modeled by a Coulomb‐type friction law with a variable friction angle below 10°. We propose that variations of the friction angle are mainly influenced by the thickness of the flowing mass.