- Open Access
On the geoelectric structure of major strike-slip faults and shear zones
Earth, Planets and Space volume 56, pages1177–1184(2004)
Magnetotelluric imaging of the San Andreas Fault has shown that seismically-active segments are characterized by a zone of low resistivity in the upper crust. Similar resistivity features are observed on other major strike-slip faults, and may have a common origin in a region of fractured rock, partially or fully saturated with groundwater. Other strike-slip faults show possible zones of reduced resistivity in the mid and lower crust that may be related to zones of ductile shear. Additional MT surveys are required to elucidate the role of fluids in controlling the seismic behaviour of major faults, both in and below the seismogenic zone. A set of synthetic inversions show that MT data is sensitive to the geoelectric structure of a shear zone at mid-crustal depths.
Anderson, J. L., R. H. Osborne, and D. E. Palmer, Cataclastic rocks of the San Gabriel Fault—an expression of deformation at deeper crustal levels in the San Andreas Fault Zone, Tectonophysics, 98, 209–251, 1983.
Archie, G. E., The electrical resistivity log as an aid in determining some reservoir characteristics, Trans. Am. Inst. Min. Metall. Pet. Eng., 146, 54–62, 1942.
Bai, D. and M. Meju, Deep structure of the Longling-Ruili fault underneath Ruili basin near the eastern Himalayan syntaxis: Insights from MT imaging, Tectonophysics, 364, 135–146, 2003.
Bakun, W. H. and A. G. Lindh, The Parkfield, California, Earthquake Prediction Experiment, Science, 229, 619–624, 1985.
Bedrosian, P. A., M. J. Unsworth, and G. D. Egbert, Magnetotelluric imaging of the creeping segment of the San Andreas Fault near Hollister, Geophys. Res. Lett., 29, 1506, doi:10.1029/2001GL012119, 2002.
Bedrosian, P. A., M. J. Unsworth, G. D. Egbert, and C. H. Thurber, Geophysical images of the creeping segment of the San Andreas Fault: Implications for the role of crustal fluids in the earthquake process, Tectonophysics, 385, doi:10.1016/j.tecto.2004.02.010, 2004.
Blandpied, M. L., D. A. Lockner, and J. D. Byerlee, An earthquake mechanism based on rapid sealing of faults, Nature, 358, 574–576, 1992.
Byerlee, J., Model for episodic flow of high pressure water in fault zones before earthquakes, Geology, 21, 303–306, 1993.
Chester, F. M., J. P. Evans, and R. L. Biegel, Internal structure and weakening mechanisms of the San Andreas Fault, J. Geophys. Res., 98, 771–786, 1993.
Clark, M. K. and L. H. Royden, Topographic ooze: Building the Eastern margin of Tibet by lower crustal flow, Geology, 28, 703–706, 2000.
Eberhart-Phillips, D., V. F. Labson, W. D. Stanley, A. J. Michael, and B. D. Rodriguez, Preliminary velocity and resistivity models of the Loma Prieta earthquake region, Geophys. Res. Lett., 17, 1235–1238, 1990.
Electromagnetic Research Group for the Active Fault, Low electrical resistivity along an active fault, J. Geomag. Geoelectr., 34, 103–127, 1982.
Hickman, S., M. Zoback, and W. Ellsworth, Introduction to special section: Preparing for the San Andreas Fault Observatory at Depth, Geophys. Res. Lett., 31, L12S01, doi:10.1029/2004GL020688, 2004.
Hoffman-Rothe, A., O. Ritter, and C. Janssen, Correlation of electrical conductivity an structural damage at a major strike-slip fault in Northern Chile, J. Geophys. Res., 109, doi:10.1029/2004JB003030, 2004.
Irwin, W. P. and I. Barnes, Effect of geologic structure and metamorphic fluids on seismic behavior of the San Andreas Fault system in central and northern California, Geology, 3,, 1975.
Janssen, C., A. Hoffman-Rothe, S. Tauber, and H. Wilke, Internal structure of the pre-cordilleran fault system (Chile)—insights from structural and geophysical observations, J. Structural Geology, 24, 123–143, 2002.
Johnson, P. A. and T. V. McEvilly, Parkfield seismicity: Fluid-driven?, J. Geophys. Res., 100, 12,937–12,950, 1995.
Jones, A. G., R. D. Kurtz, D. E. Boerner, J. A. Craven, McG. W. Neice, D. I. Gough, J. M. DeLaurier, and R. G. Ellis, Electromagnetic constraints on strike-slip fault geometry—The Fraser River Fault System, Geology, 20, 561, 1992a.
Jones, A. G., Electrical conductivity of the continental lower crust, in Continental Lower Crust, edited by D. M. Fountain, R. J. Arculus, and R. W. Kay, Elsevier, Amsterdam, Chapter 3: pp. 81–143, 1992b.
Mackie, R. L., D. W. Livelybrooks, T. R. Madden, and J. C. Larsen, A magnetotelluric investigation of the San Andreas Fault at Carrizo Plain, California, Geophys. Res. Lett., 24, 1847–1850, 1997.
Madden, T. R., G. A. LaTorraca, and S. K. Park, Electrical conductivity variations around the Palmdale section of the San Andreas Fault Zone, J. Geophys. Res., 98, 795–808, 1993.
Mazella, A. and H. F. Morrison, Electrical resistivity variations associated with earthquakes on the San Andreas Fault, Science, 185, 855–857, 1974.
Mitsuhata, Y., Y. Ogawa, M. Mishina, T. Kono, T. Yokokura, and T. Uchida, Electromagnetic heterogeneity of the seismogenic region of 1962 M6.5 Northern Miyagi Earthquake, northeastern Japan, Geophys. Res. Lett., 28(23), 4371–4374, 2001.
Nadeau, R. M., W. Foxall, and T. V. McEvilly, Clustering and periodic recurrence of microearthquakes on the San Andreas Fault at Parkfield, California, Science, 267, 503–507, 1995.
Ogawa, Y., M. Mishina, T. Goto, H. Satoh, N. Oshiman, T. Kasaya, Y. Takahashi, T. Nishitani, S. Sakanaka, M. Uyeshima, Y. Takahashi, Y. Honkura, and M. Matsushima, Magnetotelluric imaging of fluids in intraplate earthquake zones, NE Japan back arc, Geophys. Res. Lett., 28(19), 3741–3744, 2001.
Ritter, O., T. Ryberg, U. Weckmann, A. Hoffmann-Rothe, A. Abueladas, Z. Garfunkel, and DESERT Research Group, Geophysical images of the Dead Sea Transform in Jordan reveal an impermeable barrier for fluid flow, Geophys. Res. Lett., 30(14), 1741, doi:10.1029/2003GL017541, 2003.
Ritter, O., A. Hoffman-Rothe, P. A. Bedrosian, U. Weckmann, and V. Haak, Electrical conductivity images of active and fossil fault zones, in Microstuctural Evolution and Physical Properties in High Strain Zones, Geological Society of London Special Publications, 2004 (in press).
Rodi, W. and R. L. Mackie, Nonlinear conjugate gradients algorithm for 2-D magnetotelluric inversion, Geophysics, 66, 174–187, 2001.
Sun, J., G. Jin, D. Bai, and L. Wang, Sounding of electrical structure of the crust and upper mantle along the eastern border of Qinghai-Tibet plateau and its tectonic significance, Science in China (Series D), 46, 243–253, 2003.
Tank, S. B., Y. Honkura, Y. Ogawa, N. Oshiman, M. K. Tunçer, M. Matsushima, C. Çelik, E. Tolak, and A. M. Işikara, Resistivity structure in the western part of the fault rupture zone associated with the 1999 İzmit earthquake and its seismogenic implication, Earth Planets Space, 55, 437–442, 2003.
Tank, S. B., Y. Honkura, Y. Ogawa, M. Matsushima, N. Oshiman, M. K. Tuncer, C. Celik, E. Tolak, and A. M. Isikara, Magnetotelluric imaging of the fault rupture area of the 1999 Izmit (Turkey) earthquake, Physics of the Earth and Planetary Interiors, 2004 (in press).
Tapponnier, P., Xu Zhiqin, F. Roger, B. Meyer, N. Arnaud, G. Wittlinger, and Y. Jingsui, Oblique stepwise rise and growth of the Tibetan Plateau, Science, 294, 1671–1677, 2001.
Thurber, C. and S. Roecker, Two-dimensional seismic image of the San Andreas Fault in the Northern Gabilan Range, central California: Evidence for fluids in the fault zone, Geophys. Res. Lett., 24, 1591–1594, 1997.
Thurber, C., S. Roecker, K. Roberts, M. Gold, L. Powell, and K. Rittger, Earthquake locations and three-dimensional fault zone structure along the creeping section of the San Andreas Fault near Parkfield, CA: Preparing for SAFOD, Geophys. Res. Lett., 31, doi:10.1029/2002GL016004, 2003.
Unsworth, M. J., G. D. Egbert, and J. R. Booker, High Resolution electromagnetic imaging of the San Andreas Fault in Central California, J. Geophys. Res., 104, 1131–1150, 1999.
Unsworth, M. J., M. Eisel, G. D. Egbert, W. Siripunarvaporn, and P. A. Bedrosian, Along-strike variations in the structure of the San Andreas Fault at Parkfield, California, Geophys. Res. Lett., 27, 3021–3024, 2000.
Unsworth, M. J., W. Wei, A. G. Jones, S. Li, P. A. Bedrosian, J. R. Booker, S. Jin, and M. Deng, Crustal and upper mantle structure of Northern Tibet imaged with magnetotelluric data, J. Geophys. Res., 109, doi:10.1029/2002JB002305, 2004.
Wannamaker, P. E., Affordable magnetotellurics: Interpretation in natural environments, in Three-dimensional Electromagnetics, edited by M. Oristaglio and B. Spies, Geophys. Devel. Ser., no. 7, Soc. Expl. Geophys., pp. 349–374, 1999.
Wannamaker, P. E., Comment on “The petrologic case for a dry lower crust” by B. W D. Yardley and J. W Valley, J. Geophys. Res., 105(B3), 6057–6064, 10.1029/1999JB900324, 2000.
Wannamaker, P. E., G. R. Jiracek, J. A. Stodt, T. G. Caldwell, V. Gonzalez, J. McKnight, and A. D. Porter, Fluid generation and pathways beneath an active compressional orogen, the New Zealand Southern Alps, inferred from magnetotelluric data, J. Geophys. Res., 107, 2001JB000186, 2002.
Yardley, B. W. D. and J. W. Valley, The petrologic case for a dry lower crust, J. Geophys. Res., 102, 12173, 1997.
About this article
Cite this article
Unsworth, M., Bedrosian, P.A. On the geoelectric structure of major strike-slip faults and shear zones. Earth Planet Sp 56, 1177–1184 (2004). https://doi.org/10.1186/BF03353337
- shear zones
- strike-slip faults
- earthquake cycle
- San Andreas Fault