Fluid-rock reaction weakening of fault zones Academic Article uri icon

abstract

  • The presence of weak phyllosilicates may explain the low shear strengths of fault zones if they define well-developed fabrics. The growth of phyllosilicates is favored in meteoric water-dominated granitic fault systems. Where phyllosilicates precipitate in active fault zones, they contribute directly to reaction softening. Because low-temperature deformation of phyllosilicates is not governed by frictional processes alone but can occur by pressure-independent dislocation glide, the strength of phyllosilicate-rich fault rocks can be low at all depths. Low strain rate creep during interseismic periods can align phyllosilicate grains in foliated gouge and phyllonites. Where preferred orientations are strong and continuity of phyllosilicates is large, strengths of rocks within fault zones may approach minimum strengths defined by single phyllosilicate crystals. -from Authors

published proceedings

  • Journal of Geophysical Research: Solid Earth

author list (cited authors)

  • Wintsch, R. P., Christoffersen, R., & Kronenberg, A. K

citation count

  • 305

complete list of authors

  • Wintsch, RP||Christoffersen, R||Kronenberg, AK

publication date

  • July 1995