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Using a Damage Approach to Model Pre-Eruptive Surface Displacements and Help Forecast Volcanic Eruptions

Jean-Luc Got1, Aline Peltier2, Valérie Ferrazzini2, David Marsan1

  • Affiliations:  1Univ. Grenoble Alpes, Univ. Savoie Mont‐Blanc, CNRS, IRD, Univ. Gustave Eiffel, ISTerre, Grenoble, France ; 2Observatoire Volcanologique du Piton de la Fournaise, IPGP, Sorbonne Paris Cit., UMR, CNRS, Paris, France 

  • Presentation type: Talk

  • Presentation time: Monday 10:30 - 10:45, Room S160

  • Programme No: 2.4.7

  • Theme 2 > Session 4

Abstract

Volcanic processes are various and controlled by a large number of parameters, which makes difficult complete studies of the volcano surface deformation and seismicity involving the coupled magma and edifice processes. One approach may be to study basaltic volcanoes, where magma is expected to be less compressible than in andesitic explosive volcanoes, and far less compressible than the volcanic edifice. It allows focusing research on the edifice constitutive laws, and their expression using geophysical observables. Volcano-tectonic seismicity may be used in modelling surface displacements before an eruption, using a damage approach and a simple magma pressurization model. It allows computing the time variations of the magma reservoir pressure and magma-edifice interaction power. When crack interaction reaches a sufficiently high level in the pressurized volcanic edifice (that is, when earthquake cumulative number exhibits some acceleration), the magma-edifice interaction power exhibits a maximum shortly before the eruption. At Piton de la Fournaise, the study of 24 summit-proximal eruptions recorded from 2003 to 2017 allows evidencing a relation between the times of this maximum and of the eruption. Applications will be presented to show how this knowledge could be used for forecasting these eruptions. Benefits of using INSAR with GPS data, and possible extension of this approach to andesitic explosive volcanoes will be discussed.