Dondin F., Lebrun J. F., Kelfoun Karim, Fournier N., Randrianasolo A.
Source
Bulletin of Volcanology, 2012,
74 (2), p. 595-607 ISSN 0258-8900
Kick 'em Jenny volcano is the only known active submarine volcano in the Lesser Antilles. It lies within a horseshoe-shaped structure open to the west northwest, toward the deep Grenada Basin. A detailed bathymetric survey of the basin slope at Kick 'em Jenny and resulting high-resolution digital elevation model allowed the identification of a major submarine landslide deposit. This deposit is thought to result from a single sector collapse event at Kick 'em Jenny and to be linked to the formation of the horseshoe-shaped structure. We estimated the volume and the leading-edge runout of the landslide to be ca. 4.4 km(3) and 14 km, respectively. We modelled a sector collapse event of a proto Kick 'em Jenny volcano using VolcFlow, a finite difference code based on depth-integrated mass and momentum equations. Our models show that the landslide can be simulated by either a Coulomb-type rheology with low basal friction angles (5.5A degrees-6.5A degrees) and a significant internal friction angle (above 17.5A degrees) or, with better results, by a Bingham rheology with low Bingham kinematic viscosity (0 < nu (B) < 30 m(2)/s) and high shear strength (130 < I-3 a parts per thousand currency signaEuro parts per thousand 180 m(2)/s(2)). The models and the short runout distance suggest that the landslide travelled as a stiff cohesive flow affected by minimal granular disaggregation and slumping on a non-lubricated surface. The main submarine landslide deposit can therefore be considered as a submarine mass slide deposit that behaved like a slump.
Plan de classement
Sciences fondamentales / Techniques d'analyse et de recherche [020]
;
Géologie et formations superficielles [064]
