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Journal of Geophysical Research 115 (2010) 06406
Morphological instabilities of stressed and reactive geological interfaces
Luiza Angheluta 1, Joachim Mathiesen 1, Chaouqi Misbah 2, François Renard 1, 3

Interfaces between contacting rocks of the Earth's crust are shown to be unstable and corrugating and develop roughness at various scales when submitted to nonhydrostatic stress. This instability may occur in various geological settings as long as a coherent deformation of the interface is allowed and the bodies that the interface separates have different material properties (i.e., viscosity, density, or elastic moduli). Relevant examples include fault planes, dissolution interfaces, or grain boundaries. Performing a two-dimensional linear stability analysis, we consider two cases: one solid in contact with a viscous layer and two solids separated by a thin viscous layer. In both cases either shear and/or normal loads are imposed on the interface and thermodynamical conditions for the initiation of roughening are established. Applied on several geological systems such as grain contacts and fault planes, we propose that our analysis can explain how complex patterns may emerge at rock-rock interfaces. Finally, we provide an analysis of the evolution of the static friction coefficient along sheared interfaces. The evolution is shown to depend solely on Poisson's ratio of the solid and the ratio of the shear and compressional stresses along the interface.
1 :  Physics of Geological Processes (PGP)
University of Oslo
2 :  Laboratoire de Spectrométrie Physique (LSP)
CNRS : UMR5588 – Université Joseph Fourier - Grenoble I
3 :  Laboratoire de géodynamique des chaines alpines (LGCA)
CNRS : UMR5025 – OSUG – INSU – Université de Savoie – Université Joseph Fourier - Grenoble I
Planète et Univers/Sciences de la Terre/Géomorphologie
Structural Geology: Rheology: general (8160) – Tectonophysics: Dynamics and mechanics of faulting (8004) – Tectonophysics: Rheology: crust and lithosphere (8031) – Structural Geology: Dynamics and mechanics of faulting (8118) – Seismology: Theory