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Large-scale sliding induced by sill intrusions at Réunion Island: insights from numerical modeling

By Marie Chaput, Virginie Pinel, Vincent Famin and Laurent Michon

Abstract

International audienceRecent structural analysis of outcrops at Piton des Neiges, the eroded shield volcano of La Réunion Island, show that co-and/or post-intrusive sliding occurs at sills, located at deep level, along a detachment. We performed a 2D numerical study to quantify the perturbation induced by sill injection within a volcanic edifice. Magma is considered as an inviscid and pressurized fluid injected in an initially stable edifice under gravity-controlled extension. Displacements along the detachment are controlled by a friction law. We show that sill injection always induces tangential displacements. This effect is strongly increased when sills are emplaced along a detachment rather than in an homegeneous edifice. In this case, the magma injection produces extension behind the intrusion and potentially ends up in a large-scale flank collapse. Sill injections can thus explain the co-intrusive shear deformation observed at Piton des Neiges and the tangential displacements measured at Piton de la Fournaise during the 2007 eruption

Topics: [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences
Publisher: HAL CCSD
Year: 2014
OAI identifier: oai:HAL:hal-01387001v1

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