Effects of normal stress variation on the strength and stability of creeping faults

M. S. Boettcher, Chris J. Marone

Research output: Contribution to journalArticle

36 Citations (Scopus)

Abstract

A central problem in studies of fault interaction and earthquake triggering is that of quantifying changes in frictional strength and the constitutive response caused by dynamic stressing. We imposed normal stress vibrations on creeping laboratory shear zones to investigate the process of dynamic weakening and the conditions under which resonant frictional behavior occurs. Layers of quartz powder were sheared at room temperature in a double-direct shear geometry at normal stress ̄σn = 25 200 MPa, vibration amplitude A = 0.1 - 10 MPa, period T = 0.1 -200 s, and loading rate V = 1-1000 μm/s. Frictional response varied systematically with A, T, and V. Small-amplitude, short-period vibrations had no effect on frictional strength, but large-amplitude, short-period vibrations reduced shear zone strength by about 1%. Intermediate periods caused phase lags between shear strength and imposed vibrations. During long-period vibrations, frictional strength varied sinusoidally, in phase with vibrations and with an amplitude consistent with a constant coefficient of friction. Our data show that friction exhibits a critical vibration period, as predicted by theory. At long periods, the Dieterich (aging) friction law, with the Linker and Dieterich modification to describe step changes in normal stress, provides a good fit to our experimental results for all A and V. At short periods, however, theory predicts more dynamic weakening than we observed experimentally, suggesting that existing rate and state friction laws do not account for the full physics of our laboratory experiments. Our data show that normal-force vibrations can weaken and potentially destabilize steadily creeping fault zones.

Original languageEnglish (US)
JournalJournal of Geophysical Research: Solid Earth
Volume109
Issue number3
StatePublished - Mar 10 2004

Fingerprint

strength (mechanics)
vibration
Friction
friction
shear stress
Quartz
Shear strength
Powders
shear
Earthquakes
shear zone
Physics
Aging of materials
Geometry
effect
loading rate
shear strength
quartz
physics
earthquakes

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Oceanography
  • Forestry
  • Aquatic Science
  • Ecology
  • Condensed Matter Physics
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Physical and Theoretical Chemistry
  • Polymers and Plastics
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Materials Chemistry
  • Palaeontology

Cite this

@article{83ec2a7ef3d04ce481ee02b3352c4853,
title = "Effects of normal stress variation on the strength and stability of creeping faults",
abstract = "A central problem in studies of fault interaction and earthquake triggering is that of quantifying changes in frictional strength and the constitutive response caused by dynamic stressing. We imposed normal stress vibrations on creeping laboratory shear zones to investigate the process of dynamic weakening and the conditions under which resonant frictional behavior occurs. Layers of quartz powder were sheared at room temperature in a double-direct shear geometry at normal stress ̄σn = 25 200 MPa, vibration amplitude A = 0.1 - 10 MPa, period T = 0.1 -200 s, and loading rate V = 1-1000 μm/s. Frictional response varied systematically with A, T, and V. Small-amplitude, short-period vibrations had no effect on frictional strength, but large-amplitude, short-period vibrations reduced shear zone strength by about 1{\%}. Intermediate periods caused phase lags between shear strength and imposed vibrations. During long-period vibrations, frictional strength varied sinusoidally, in phase with vibrations and with an amplitude consistent with a constant coefficient of friction. Our data show that friction exhibits a critical vibration period, as predicted by theory. At long periods, the Dieterich (aging) friction law, with the Linker and Dieterich modification to describe step changes in normal stress, provides a good fit to our experimental results for all A and V. At short periods, however, theory predicts more dynamic weakening than we observed experimentally, suggesting that existing rate and state friction laws do not account for the full physics of our laboratory experiments. Our data show that normal-force vibrations can weaken and potentially destabilize steadily creeping fault zones.",
author = "Boettcher, {M. S.} and Marone, {Chris J.}",
year = "2004",
month = "3",
day = "10",
language = "English (US)",
volume = "109",
journal = "Journal of Geophysical Research",
issn = "0148-0227",
publisher = "American Geophysical Union",
number = "3",

}

Effects of normal stress variation on the strength and stability of creeping faults. / Boettcher, M. S.; Marone, Chris J.

In: Journal of Geophysical Research: Solid Earth, Vol. 109, No. 3, 10.03.2004.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Effects of normal stress variation on the strength and stability of creeping faults

AU - Boettcher, M. S.

AU - Marone, Chris J.

PY - 2004/3/10

Y1 - 2004/3/10

N2 - A central problem in studies of fault interaction and earthquake triggering is that of quantifying changes in frictional strength and the constitutive response caused by dynamic stressing. We imposed normal stress vibrations on creeping laboratory shear zones to investigate the process of dynamic weakening and the conditions under which resonant frictional behavior occurs. Layers of quartz powder were sheared at room temperature in a double-direct shear geometry at normal stress ̄σn = 25 200 MPa, vibration amplitude A = 0.1 - 10 MPa, period T = 0.1 -200 s, and loading rate V = 1-1000 μm/s. Frictional response varied systematically with A, T, and V. Small-amplitude, short-period vibrations had no effect on frictional strength, but large-amplitude, short-period vibrations reduced shear zone strength by about 1%. Intermediate periods caused phase lags between shear strength and imposed vibrations. During long-period vibrations, frictional strength varied sinusoidally, in phase with vibrations and with an amplitude consistent with a constant coefficient of friction. Our data show that friction exhibits a critical vibration period, as predicted by theory. At long periods, the Dieterich (aging) friction law, with the Linker and Dieterich modification to describe step changes in normal stress, provides a good fit to our experimental results for all A and V. At short periods, however, theory predicts more dynamic weakening than we observed experimentally, suggesting that existing rate and state friction laws do not account for the full physics of our laboratory experiments. Our data show that normal-force vibrations can weaken and potentially destabilize steadily creeping fault zones.

AB - A central problem in studies of fault interaction and earthquake triggering is that of quantifying changes in frictional strength and the constitutive response caused by dynamic stressing. We imposed normal stress vibrations on creeping laboratory shear zones to investigate the process of dynamic weakening and the conditions under which resonant frictional behavior occurs. Layers of quartz powder were sheared at room temperature in a double-direct shear geometry at normal stress ̄σn = 25 200 MPa, vibration amplitude A = 0.1 - 10 MPa, period T = 0.1 -200 s, and loading rate V = 1-1000 μm/s. Frictional response varied systematically with A, T, and V. Small-amplitude, short-period vibrations had no effect on frictional strength, but large-amplitude, short-period vibrations reduced shear zone strength by about 1%. Intermediate periods caused phase lags between shear strength and imposed vibrations. During long-period vibrations, frictional strength varied sinusoidally, in phase with vibrations and with an amplitude consistent with a constant coefficient of friction. Our data show that friction exhibits a critical vibration period, as predicted by theory. At long periods, the Dieterich (aging) friction law, with the Linker and Dieterich modification to describe step changes in normal stress, provides a good fit to our experimental results for all A and V. At short periods, however, theory predicts more dynamic weakening than we observed experimentally, suggesting that existing rate and state friction laws do not account for the full physics of our laboratory experiments. Our data show that normal-force vibrations can weaken and potentially destabilize steadily creeping fault zones.

UR - http://www.scopus.com/inward/record.url?scp=2542439843&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=2542439843&partnerID=8YFLogxK

M3 - Article

VL - 109

JO - Journal of Geophysical Research

JF - Journal of Geophysical Research

SN - 0148-0227

IS - 3

ER -