Skip to main content
SpringerLink
Log in

Fracturing and hydrothermal alteration in normal fault zones

  • Faulting and Crustal Deformation: Field Observations and Modeling
  • Published:
pure and applied geophysics Aims and scope Submit manuscript

Abstract

Large normal fault zones are characterized by intense fracturing and hydrothermal alteration. Displacement is localized in a slip zone of cataclasite, breccia and phyllonite surrounding corrugated and striated fault surfaces. Slip zone rock grades into fractured, but less comminuted and hydrothermally altered rock in the transition zone, which in turn grades abruptly into the wall rock. Fracturing and fluid flow is episodic, because permeability generated during earthquakes is destroyed by hydrothermal processes during the time between earthquakes.

Fracture networks are described by a fracture fabric tensor (F). The permeability tensor (k) is used to estimate fluid transport properties if the trace of F is sufficiently large. Variations in elastic moduli and seismic velocities between fault zone and wall rock are estimated as a function of fracture density (ε). Fracturing decreases elastic moduli in the transition zone by 50–100% relative to the country rock, and similar or even greater changes presumably occur in the slip zone.P-andS-wave velocity decrease, andV p /V s increases in the fault zone relative to the wall rock. Fracture permeability is highly variable, ranging between 10−13 m2 and 10−19 m2 at depths near 10 km. Changes in permeability arise from variations in effective stress and fracture sealing and healing.

Hydrothermal alteration of quartzo-feldspathic rock atT>300°C creates mica, chlorite, epidote and alters the quartz content. Alteration changes elastic moduli, but the changes are much less than those caused by fracturing.P-andS-wave velocities also decrease in the hydrothermally altered fault rock relative to the country rock, and there is a slight decrease inV p /V s , which partially offsets the increase inV p /V s caused by fracturing.

Fracturing and hydrothermal alteration affect fault mechanics. Low modulus rock surrounding fault surfaces increases the probability of exceeding the critical slip distance required for the onset of unstable slip during rupture initiation. Boundaries between low modulus fault rock and higher modulus wall rock also act as rupture guides and enhance rupture acceleration to dynamic velocity. Hydrothermal alteration at temperatures in excess of 300°C weakens the deeper parts of the fault zone by producingphyllitic mineral assemblages. Sealing of fracture in time periods between large earthquakes generates pods of abnormally pressured fluid which may play a fundamental role in the initiation of large earthquakes.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  • Becker, G. F. (1982),Geology of the Comstock Lode and the Washoe District, U.S. Geol. Surv. Monograph 3.

  • Blanpied, M. L., Lockner, D. A., andByerlee, J. D. (1992),An Earthquake Mechanism Based on Rapid Sealing of Faults, Nature358, 574–576.

    Google Scholar 

  • Boutellier, A.-M., andRobert, F. (1992),Paleoseismic Events Recorded in Archean Gold-quartz Vein Networks, Val d'Or Abitibi, Quebec, J. Struct. Geol.14, 161–179.

    Google Scholar 

  • Bruhn, R. L., Yonkee, W. T., andParry, W. T. (1990),Structural and Fluid-chemical Properties of Seismogenic Normal Faults, Tectonophysics175, 139–157.

    Google Scholar 

  • Bruhn, R. L., Gibler, P. R., andParry, W. T. (1987),Seismogenic characteristics of the Salt Lake segment, Wasatch normal fault zone. InJ. Geological Society of London (eds. Coward, M. P., Dewey, J. F., and Hancock, P. L.), Special volume on Continental Extensional Tectonics, pp. 337–353.

  • Byerlee, J. D. (1993),Model for Episodic Flow of High-pressure H 2 O in Fault Zones before Earthquakes, Geology21, 289–304.

    Google Scholar 

  • Byerlee, J. D. (1990),Friction, Overpressure and Fault Normal Compression, Geophys. Res. Letts,17, 2109–2112.

    Google Scholar 

  • Cady, C. C. (1983),Hydrothermal Alteration in the Corral Canyon Shear Zone, Mineral Mountains, Utah: With Interferences for Shearing, Univ. of Utah M. S. Thesis, 92pp.

  • Chester, F. M., Evans, J. P., andBiegel, R. L. (1993),Internal Structure and Weakening Mechanisms of the San Andreas Fault, J. Geophys. Res.98, 771–786.

    Google Scholar 

  • Chester, F. M., andLogan, J. M. (1986),Imphcations for mechanical Properties of Brittle Faults from Observations of the Punchbowl Fault Zone, California, Pure and Appl. Geophys.124, 79–106.

    Google Scholar 

  • Christensen, N. L.,Seismic velocities InPractical Handbook of Physical Properties of Rocks and Minerals (ed. Carmichael, R. S.) (CRC Press Inc., N.Y. 1989) pp. 431–534.

    Google Scholar 

  • Condie, K. C. (1960),Petrogenesis of the Mineral Range Pluton, Southwest Utah, Univ. of Utah M.S. Thesis, 76 pp.

  • Doser, D. I. (1986),Earthquake Processes in the Rainbow Mountain-Fairview Peak-Dixie Valley, Nevada Region, J. Geophys. Res.91, 12,572–12,585.

    Google Scholar 

  • Engelder, T.,Joints and shear fractures in rock. InFracture Mechanics of Rock (ed. Atkinson, B. K.) (Academic Press 1987) pp. 277–347.

  • Evans, S. H., Parry, W. T., andBruhn, R. L. (1985),Thermal, Mechanical and Chemical History of Wasatch Fault Cataclasite and Phyllonite, Traverse Mountains Area, Salt Lake City, Utah: Age and Uplift Rates from K/Ar andFissions Track Measurements, U.S. Geol. Surv. Open-File Report86-31, 410–413.

    Google Scholar 

  • Gilbert, G. K. (1928),Studies of Basin and Range Structures, U.S. Geol. Surv. Prof. Paper153, 92 pp.

  • Gillespie, P. A., Howard, C. B., Walsh, J. J., andWatterson, J. (1993),Measurements and Characteristics of Spatial Distribution of Fractures, Tectonophysics226, 113–141.

    Google Scholar 

  • Harris, C., Franssen, R., andLoosveld, R. (1991),Fractal Analysis of Fractures in Rocks: The Cantor's Dust Method—Comment, Tectonophysics198, 107–115.

    Google Scholar 

  • Hill, R. (1952),The Elastic Behavior of a Crystalline Aggregate, Proc. Phys. Soc. London, Sect.A65, 349.

    Google Scholar 

  • Hudson, D. M.,The Comstock District Nevada. InCrustal Evolution of the Great Basin and Sierra Nevada: Cordilleran/Rocky Mountain Section (eds. Lahren, M. M., Trexler, J. H., Jr, and Spinosa, C.), Geol. Soc. Amer. Guidebook (Dept. of Geological Sciences, University of Nevade, Reno 1993) pp. 481–496.

    Google Scholar 

  • Janecke, S. U., andEvans, J. P. (1988),Feldspar-influenced Rock Rheologies. Geology16, 1064–1067.

    Google Scholar 

  • Kowallis, B. J., Ferguson, J., andJorgensen, G. J. (1990),Uplift along the Salt Lake Segment of the Wasatch Fault from Apatite and Zircon Fission Track Dating in the Little Cottonwood Stock, Nucl. Tracks Radiat. Meas.17, 325–329.

    Google Scholar 

  • Li-Yong-Gang, Leary, P., Aki, K., andMalin, P. (1990),Seismic Trapped Modes in the Oroville and San Andreas Fault Zones, Science249, 763–767.

    Google Scholar 

  • Mitra, G. (1978),Ductile Deformation Zones and Mylonites: The Mechanical Processes Involved in the Deformation of Crystalline Basement Rocks, Am. J. Sci.278, 1057–1084.

    Google Scholar 

  • Neilson, D. L., Evans, S. H., Jr., andSibbett, B. S. (1986),Magnetic, Structural and Hydrothermal Evolution of the Mineral Mountains Intrusive Complex, Utah, Geol. Soc. Am. Bull.97, 765–777.

    Google Scholar 

  • Oda, M., Hatsuyama, Y., andOhnishi, Y. (1987),Numerical Experiments on Permeability Tensor and its Application to Jointed Granite at the Stripa Mine, Sweden, J. Geophys. Res.92, 8037–8048.

    Google Scholar 

  • Oda, M. (1986),An Equivalent Continuum Model for Coupled Stress and Fluid Flow Analysis in Jointed Rock Masses, Water Resources Res.22, 1845–1856.

    Google Scholar 

  • Oda, M., Yamabe, T., andKamemura, K. (1986),A Crack Tensor and its Relation to Wave Velocity Anisotropy in Jointed Rock Masses, Int. J. Rock Mech. Min. Sci. Geomech. Abstr.23, 387–397.

    Google Scholar 

  • O'Connell, R. J., andBudiansky, B. (1974),Setsmic Velocities in Saturated and Dry Cracked Solids, J. Geophys. Res.79, 5412–5426.

    Google Scholar 

  • Okaya, D. A., andThompson, G. A. (1985),Geometry of Cenozoic Extensional Faulting, Dixie Valley, Nevada, Tectonics4, 107–125.

    Google Scholar 

  • Parry, W. T., Hedderly-Smith, D., andBruhn, R. L. (1991),Fluid Inclusions and Hydrothermal Alteration on the Dixie Valley Fault, Nevada, J. Geophys. Res.96, 19,733–19,748.

    Google Scholar 

  • Parry, W. T., andBruhn, R. L. (1990),Fluid Pressure Transients on Seismogenic Normal Faults, Tectonophysics179, 335–344.

    Google Scholar 

  • Parry, W. T., Wilson, P. N., andBruhn, R. L. (1988),Pore Fluid Chemistry and Chemical Reactions on the Wasatch Normal Fault, Utah, Geochem. Cosmochem. Acta52, 2053–2063.

    Google Scholar 

  • Parry, W. T., andBruhn, R. L. (1987),Fluid Inclusion Evidence for Minimum 11 km Vertical Offset on the Wasatch Fault, Utah, Geology15, 67–70.

    Google Scholar 

  • Parry, W. T., andBruhn, R. L. (1986),Pore Fluid and Seismogenic Characteristics of Fault Rock at Depth on the Wasatch Fault, Utah, J. Geophys. Res.91, 730–744.

    Google Scholar 

  • Pollard, D. D., andSegall, P.,Theoretical displacements and stresses near fractures in rock: with applications to faults, joints, veins, dikes, and solution surfaces. InFracture Mechanics of Rock (ed. Atkinson, B. K.) (Academic Press 1987), pp. 277–347.

  • Rice, J. R., 1992,Fault stress states, pore pressure distributions, and the weakness of the San Andreas fault. InFault Mechanics and Transport Properties of Rocks (eds. Evans, B., and Wong, T.-F.) (Academic Press 1992) pp. 475–504.

  • Rubin, A. M., andParker, C. B.,Near-tip stress fields for dynamically propagating Mode-II fractures. InThe Mechanical Involvement of Fluids in Faulting — Extended Abstracts. U. S. Geol. Surv. Red Book Conference, Tenaya Lodge, Fish Camp, CA (June 6–10, 1993).

  • Schwartz, D. P., andCoppersmith, K. J. (1984),Fault Behavior and Characteristic Earthquakes —Examples from the Wasatch and San Andreas Fault Zones, J. Geophys. Res.89, 5681–5698.

    Google Scholar 

  • Sibson, R. H. (1993),Load-strengthening versus Load-weakening Faulting, J. Struct. Geol.15, 123–128.

    Google Scholar 

  • Sibson, R. H. (1992),Implications of Fault-valve Behavior for Rupture Nucleation and Recurrence, Tectonophysics211, 283–293.

    Google Scholar 

  • Sibson, R. H. (1989),Earthquake Faulting as a Structural Process, J. Struct. Geol.11, 1–14.

    Google Scholar 

  • Scholz, C. H.,The Mechanics of Earthquakes and Faulting (Cambridge University Press 1991) 439 pp.

  • Shea, W. T., Jr., andKronenberg, A. K. (1994),Strength and Anisotropy of Foliated Rock with Varied Mica Content, J. Struct. Geology, in press.

  • Slemmons, D. B. (1957),Geological Effects of the Dixie Valley-Fairview Peak, Nevada, Earthquakes of December 16, 1954, Bull. Seismol. Soc. Am.47, 353–375.

    Google Scholar 

  • Smith, R. B., andBruhn, R. L. (1984),Intraplate Extensional Tectonics of the Eastern Basin-Range: Inferences on Structural Style from Seismic Reflection Data, Regional Geophysics and Thermal-mechanical Models of Brittle-ductile Deformation, J. Geophys. Res.87, 5733–5762.

    Google Scholar 

  • Speed, R. C., andArmstrong, R. L. (1971),Potassium-Argon Ages of some Minerals from Igneous Rocks of Western Nevada, Isochron/West71-1, 1–8.

    Google Scholar 

  • Thompson, G. A., andBurke, D. B. (1973),Rate and Direction of Spreading in Dixie Valley, Basin and Range Province, Nevada, Geol. Soc. Am. Bull.84, 627–632.

    Google Scholar 

  • Thompson, T. (1988),Fracturing in the Wasatch Fault Zone, Utah, University of Utah M.S. Thesis, 120 pp.

  • Velde, B., Dubois, J., Touchard, G., andBadri, G. (1990),Fractal Analysis of Fractures in Rocks: The Cantor's Dust Method, Tectonophysics179, 345–352.

    Google Scholar 

  • Vikre, P. G. (1989),Fluid-mineral Relations in the Comstock Lode, Economic Geology84, 1574–1613.

    Google Scholar 

  • Villaescusa, E., andBrown, E. T. (1992),Maximum Likelihood Estimation of Joint Size from Trace Length Measurements, Rock Mech. and Rock Eng.25, 67–88.

    Google Scholar 

  • Warburton, P. M. (1980),A Stereological Interpretation of Joint Trace Data, Int. J. Rock Mech. Min. Sci. and Geomech. Abstr.17, 181–190.

    Google Scholar 

  • Weertman, J. (1980),Unstable Slippage across a Fault that Separates Elastic Media of Different Elastic Constants, J. Geophys. Res.85, 1455–1461.

    Google Scholar 

  • Wilden, R., andSpeed, R. C. (1974),Geology and Mineral Resources of Churchill County, Nevada, Nevada Bureau of Mines and Geology Bulletin83, 95 pp.

  • Yonkee, W. A., andBruhn, R. L.,Geometry and Mechanics of a structural boundary, Wasatch fault zone, Utah. InStructural Properties of the American Fork, Provo and Spanish Fork Subsegments, Wasatch Normal Fault Zone, Utah (eds. Bruhn, R. L., Lee, J-J., and Yonkee, W. A.) Utah Geological and Mineral Survey Open-File Report (1990) # 186, 50 pp.

  • Yusas, M. R. (1979),Structural Evolution of the Roosevelt Hot Springs Geothermal Reservoir, University of Utah M.S. Thesis, 120 pp.

  • Zoback, M. D. (1991),State of Stress and Crustal Deformation along Weak Transform Faults, Trans. Roy. Soc. London, Series A337, 141–150.

    Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Department of Geology and Geophysics, University of Utah, 84112, Salt Lake City, UT, USA

    Ronald L. Bruhn, William T. Parry & Troy Thompson

  2. Department of Geology, Weber State University, 84408, Ogden, UT, USA

    William A. Yonkee

Authors
  1. Ronald L. Bruhn
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. William T. Parry
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. William A. Yonkee
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Troy Thompson
    View author publications

    You can also search for this author in PubMed Google Scholar

Rights and permissions

Reprints and permissions

About this article

Cite this article

Bruhn, R.L., Parry, W.T., Yonkee, W.A. et al. Fracturing and hydrothermal alteration in normal fault zones. PAGEOPH 142, 609–644 (1994). https://doi.org/10.1007/BF00876057

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF00876057

Key words

Search

Navigation