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

Anne Le Friant (1) , Philippe Heinrich (2) , Christine Deplus (1) , Georges Boudon (1)

1 IPGP - Institut de Physique du Globe de Paris
2 DAM/DIF - DAM Île-de-France

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 km 3) 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.

Domaines: Volcanologie; Géophysique [physics.geo-ph]

Anne Le Friant, Philippe Heinrich, Christine Deplus, Georges Boudon. Numerical simulation of the last flank-collapse event of Montagne Pelée, Martinique, Lesser Antilles. Geophysical Research Letters, 2003, 30 (2), ⟨10.1029/2002GL015903⟩. ⟨insu-01586350⟩