Slip on 'weak' faults by the rotation of regional stress in the fracture damage zone

D. R. Faulkner, T. M. Mitchell, David Healy, M. J. Heap

Research output: Contribution to journalArticle

231 Citations (Scopus)

Abstract

Slip on unfavourably oriented faults with respect to a remotely applied stress is well documented and implies that faults such as the San Andreas fault(1) and low- angle normal faults(2) are weak when compared to laboratory-measured frictional strength(3). If high pore pressure within fault zones is the cause of such weakness, then stress reorientation within or close to a fault is necessary to allow sufficient fault weakening without the occurrence of hydrofracture(4). From field observations of a major tectonic fault, and using laboratory experiments and numerical modelling, here we show that stress rotation occurs within the fractured damage zone surrounding faults. In particular, we find that stress rotation is considerable for unfavourably oriented 'weak' faults. In the 'weak' fault case, the damage-induced change in elastic properties provides the necessary stress rotation to allow high pore pressure faulting without inducing hydrofracture.

Original languageEnglish
Pages (from-to)922-925
Number of pages4
JournalNature
Volume444
Issue number7121
DOIs
Publication statusPublished - 14 Dec 2006

Keywords

  • San Andreas fault
  • internal structure
  • friction
  • growth
  • system
  • mechanics
  • fluids
  • rocks

Cite this