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(De)compaction of porous viscoelastoplastic media: Solitary porosity waves
Author(s) -
Yarushina Viktoriya M.,
Podladchikov Yuri Y.,
Connolly James A. D.
Publication year - 2015
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.983
H-Index - 232
eISSN - 2169-9356
pISSN - 2169-9313
DOI - 10.1002/2014jb011260
Subject(s) - porosity , compaction , porous medium , geology , buoyancy , mechanics , poromechanics , viscoelasticity , rheology , geotechnical engineering , materials science , composite material , physics
Buoyancy‐driven flow in deformable porous media is important for understanding sedimentary compaction as well as magmatic and metamorphic differentiation processes. Here mathematical analysis of the viscoplastic compaction equations is used to develop an understanding of the porosity wave instability and its sensitivity to the choice of rheological model. The conditions of propagation, size, speed, and shape of the porosity waves depend strongly on the properties of the solid rock frame. Whereas most of the previous studies on porosity waves were focused on viscous or viscoelastic mode, here we consider the ability of a solid matrix to undergo simultaneous plastic (rate‐independent) and viscous (rate‐dependent) deformation in parallel. Plastic yielding is identified as a cause of compaction‐decompaction asymmetry in porous media—this is known to lead to a strong focusing of porous flow. Speed and amplitude of a porosity wave are given as functions of material parameters and a volume of a source region. Formulation is applicable to fluid flow in sedimentary rocks where viscous deformation is due to pressure solution as well as in deep crustal or upper mantle rocks deforming in a semibrittle regime.