Details

• Dra. Marina Rosas-Carbajal, Institut de Physique du Globe de Paris, França
• Date: June, 8, 2016 12:00 am
• Place: Sala de Juntes de la Facultat de Geologia (UB)
• Location: C/ Solé i Sabarís s/n, Barcelona
• Further information: Pilar Queralt (UB)

Abstract

Catastrophic collapses of the flanks of stratovolcanoes constitute a major hazard threatening numerous lives in many countries. Many of these collapses are not associated with magmatic reawakening but are triggered by a combination of forcing agents such as pore-fluid pressurisation and/or mechanical weakening of the volcanic edifice. The volume of altered rock available for collapse, the dynamics of the hydrothermal fluid reservoir and the geometry of incipient collapse failure planes are key parameters for edifice stability analysis and modelling that remain essentially hidden to current volcano monitoring techniques. In this talk I will present a high-resolution, 3D electrical conductivity model of the La Soufrière volcano lava dome derived from extensive electrical tomography data, together with the first results of a 3D inversion of muon tomography data to obtain a 3D density model of the volcano. Highly conductive and low-density regions identified in the lava dome are associated to fluid saturated host-rock and preferential flow of highly acid hot fluids within the dome. The electrical conductivity and density models will be interpreted with the existing wealth of geological and geochemical data on the volcano to demonstrate the influence of the hydrothermal system dynamics on the hazards associated to collapse-prone altered volcanic edifices.