Cointrusive shear displacement by sill intrusion in a detachment: A numerical approach. Issue 6 (24th March 2014)

• Record Type: Journal Article
• Authors: Chaput, Marie; Pinel, Virginie; Famin, Vincent; Michon, Laurent; Froger, Jean‐Luc
• Is Part Of: Geophysical research letters. Volume 41:Issue 6(2014:Mar.)
• Page Start: 1937
• Page End: 1943
• Publication Date: 2014-03-24
• Subjects: Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2013GL058813
• Languages: English
• ISSNs: 0094-8276

Abstract

<abstract abstract-type="main"> <title>Abstract</title> <p>Sheared sills are observed at Piton des Neiges (the eroded basaltic volcano of La Réunion) and are a suspected cause of the coeruptive flank displacement of Piton de la Fournaise in 2007. We performed a 2‐D 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. Two cases of injection are tested, in an elastic homogeneous edifice or along a detachment controlled by a friction law. We show that sill injection induces tangential displacements. This effect is strongly increased when sills are emplaced along a detachment, producing extension behind the injection and potentially ending in a large‐scale flank collapse. Sill injections can thus explain the cointrusive shear deformation observed at Piton des Neiges and the tangential displacements measured at Piton de la Fournaise in 2007.</p> </abstract>