Stabilization of rapid frictional slip on a weakening fault by dilatant hardening.

J. W. Rudnicki, C. H. Chen

Research output: Contribution to journalArticlepeer-review

99 Scopus citations


Frictional slip is often accompanied by dilatancy due to uplift in sliding over asperities and microcracking in the adjacent material. If dilatancy occurs more rapidly than pore fluid can flow into the newly created void space, the local pore pressure is reduced and the effective normal stress is increased in compression, tending to inhibit further slip. This dilatant hardening is analyzd for a simple model. In the absence of pore fluid effects an instability corresponding to an unbounded slip rate occurs when the slope of the shear stress versus slip relation is more negative than the unloading stiffness of the surrounding material. Dilatant hardening prevents this instability provided that the pore pressure in the reservoir is high enough. If the pressure in the reservoir is too low, the pressure at the fault surface can be reduced to the point at which the pore fluid bulk modulus decreases rapidly, eliminating the stabilizing effect. When the anlaysis is modified to include normal stress changes simulating those in the axisymmetric compression test, the prediction of the critical pressure in the reservoir agrees to within a factor of 2 or 3 with that observed by Martin in tests on Westerly granite.-from Authors

Original languageEnglish (US)
Pages (from-to)4745-4757
Number of pages13
JournalJournal of Geophysical Research
Issue numberB5
StatePublished - 1988
Externally publishedYes

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Materials Chemistry
  • Polymers and Plastics
  • Physical and Theoretical Chemistry


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