Shallow Composition and Structure of the Upper Part of the Exhumed San Gabriel Fault, California: Implications for Fault Processes
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Abstract
Quantifying shallow fault zone structure and characteristics is critical for accurately modeling the complex mechanical behavior of earthquakes as energy moves within faults from depth. We examine macro- to microstructures, mineralogy, and properties from drill core analyses of fault-related rocks in the steeply plunging ALT-B2 geotechnical borehole (total depth of 493 m) across the San Gabriel Fault zone, California. We use macroscopic drill core and outcrop-sample analyses, core-based damage estimates, optical microscopy, and X-ray diffraction mineralogic analyses to determine the fault zone structure, deformation mechanisms, and alteration patterns of exhumed deformed rocks formed in a section of the fault that slipped 5-12 million years ago, with evidence for some Quaternary slip. The fault consists of two principal slip zones composed of cohesive cataclasite, ultracataclasite, and intact clay-rich, highly foliated gouge within upper and lower damage zones 60 m and 50 m thick. The upper 6.5 m thick principal slip zone separates Mendenhall Gneiss and Josephine Granodiorite, and a lower 11 m thick principal slip is enclosed within the Josephine Granodiorite. Microstructures record overprinted brittle fractures, cohesive cataclasites, veins, sheared clay-rich rocks, and folded foliated and carbonate-rich horizons in the damage zones. Carbonate veins are common in the lower fault zone, and alteration and mineralization assemblages consist of clays, epidote, calcite, zeolites, and chloritic minerals. These data show that shallow portions of the fault experienced fluid-rock interactions that led to alteration, mineralization, and brittle and semi-brittle deformation that led to the formation of damage zones and narrow principal slip zones that are continuous down-dip and along strike.
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References
Allmendinger, R. W., N. Cardozo, and D. M. Fisher (2011), Structural Geology Algorithms: Vectors and Tensors, Cambridge University Press.
Anderson, J. L., R. H. Osborne, and D. F. Palmer (1983), Cataclastic rocks of the San Gabriel fault—an expression of deformation at deeper crustal levels in the San Andreas fault zone, Tectonophysics, 98(3-4), 209–251, doi: 10.1016/0040-1951(83)90296-2.
Aydan, Ö., R. Ulusay, and N. Tokashiki (2014), A new rock mass quality rating system: Rock mass quality rating (RMQR) and its application to the estimation of geomechanical characteristics of rock masses, Rock Mechanics and Rock Engineering, 47(4), 1255–1276, doi: 10.1007/s00603-013-0462-z.
Barber, D. J., and H.-R. Wenk (1979), Deformation twinning in calcite, dolomite, and other rhombohedral carbonates, Physics and Chemistry of Minerals, 5(2), 141–165, doi: 10.1007/BF00307550.
Barth, A. P., and P. L. Ehlig (1988), Geochemistry and petrogenesis of the marginal zone of the Mount Lowe Intrusion, central San Gabriel Mountains, California, Contributions to mineralogy and petrology. Beitrage zur Mineralogie und Petrologie, 100(2), 192–204, doi: 10.1007/BF00373585.
Barth, A. P., J. L. Wooden, R. M. Tosdal, and J. Morrison (1995a), Crustal contamination in the petrogenesisof a calc-alkalic rock series: Josephine Mountain intrusion, California, GSA Bulletin, 107(2), 201–212, doi: 10.1130/0016-7606(1995)107<0201:CCITPO>2.3.CO;2.
Barth, A. P., J. L. Wooden, R. M. Tosdal, J. Morrison, D. L. Dawson, and B. M. Hernly (1995b), Origin of gneisses in the aureole of the San Gabriel anorthosite complex and implications for the Proterozoic crustal evolution of southern California, Tectonics, 14, 736–752, doi: 10.1130/0016-7606(1995)107<0201:CCITPO>2.3.CO;2.
Beyer, L. A., T. H. McCulloh, R. E. Denison, R. W. Morin, R. J. Enrico, J. A. Barron, and R. J. Fleck (2009), Post-Miocene right separation on the San Gabriel and Vasquez Creek faults, with supporting chronostratigraphy, western San Gabriel Mountains California, Tech. rep., U.S. Geological Survey.
Bieniawski, Z. T. (1989), Engineering rock mass classifications: A complete manual for engineers and geologists in mining, civil, and petroleum engineering, 250 pp., John Wiley & Sons, Nashville, TN.
Bieniawski, Z. T. (1993), 22 - Classification of Rock Masses for Engineering: The RMR System and Future Trends, in Rock Testing and Site Characterization, edited by J. A. Hudson, pp. 553–573, Pergamon, Oxford, doi: 10.1016/B978-0-08-042066-0.50028-8.
Blenkinsop, T. G., N. H. S. Oliver, P. G. H. M. Dirks, M. Nugus, G. Tripp, and I. Sanislav (2020), Chapter 1: Structural Geology Applied to the Evaluation of Hydrothermal Gold Deposits, in APPLIED STRUCTURAL GEOLOGY OF ORE-FORMING HYDROTHERMAL SYSTEMS, Society of Economic Geologists, doi: 10.5382/rev.21.01.
Blythe, A. E., M. A. House, and J. A. Spotila (2002), Low-temperature thermochronology of the san gabriel and san bernardino mountains, southern california: Constraining structural evolution, in Contributions to Crustal Evolution of the Southwestern United States, edited by A. Barth, Special Paper, pp. 231–250, Geological Society of America, doi: 10.1130/0-8137-2365-5.231.
Borg, I., and J. Handin (1966), Experimental deformation of crystalline rocks, Tectonophysics, 3(4), 249–367, doi: 10.1016/0040-1951(66)90019-9.
Boullier, A.-M. (2011), Fault-zone geology: lessons from drilling through the Nojima and Chelungpu faults, https://www.lyellcollection.org/doi/10.1144/SP359.2, doi: 10.1144/SP359.2, accessed: 2023-9-15.
Boulton, C., C. D. Menzies, V. G. Toy, J. Townend, and R. Sutherland (2017), Geochemical and microstructural evidence for interseismic changes in fault zone permeability and strength, Alpine Fault, New Zealand, Geochemistry, Geophysics, Geosystems, 18(1), 238–265, doi: 10.1002/2016gc006588.
Bradbury, K. K., C. R. Davis, J. W. Shervais, S. U. Janecke, and J. P. Evans (2015), Composition, Alteration, and Texture of Fault-Related Rocks from Safod Core and Surface Outcrop Analogs: Evidence for Deformation Processes and Fluid-Rock Interactions, Pure and Applied Geophysics, 172(5), 1053–1078, doi: 10.1007/s00024-014-0896-6.
Bruhn, R. L., W. T. Parry, W. A. Yonkee, and T. Thompson (1994), Fracturing and hydrothermal alteration in normal fault zones, Pure and Applied Geophysics, 142(3), 609–644, doi: 10.1007/BF00876057.
Bryant, W. A. (2017), Fault number 89c, San Gabriel fault zone, Newhall section, in Quaternary fault and fold database of the United States, https://earthquake.usgs. gov/static/lfs/nshm/qfaults/Reports/89c.pdf.
Bull, W. B. (1978), South Front of the San Gabriel Mountains, southern California, Final Technical report, Tech. rep., U.S. Geological Survey.
Caine, J. S., J. P. Evans, and C. B. Forster (1996), Fault zone architecture and permeability structure, Geology, 24(11), 1025–1028, doi: 10.1130/0091-7613(1996)024<1025:FZAAPS>2.3.CO;2.
Callahan, O. A., P. Eichhubl, and N. C. Davatzes (2020), Mineral precipitation as a mechanism of fault core growth, Journal of Structural Geology, 140, 104,156, doi: 10.1016/j.jsg.2020.104156.
Caltrans (2010), Soil and Rock Logging, Classification, and Presentation Manual, California Department of Transportation, Division of Engineering Services, Geotechnical Services.
Campbell, R. H., C. J. Wills, P. J. Irvine, and B. J. Swanson (2014), Preliminary Geologic Map of the Los Angeles 30’ x 60’ Quadrangle, California Version 2.0, Tech. rep., California Geological Survey.
Cardozo, N., and R. W. Allmendinger (2013), Spherical projections with OSXStereonet, Computers & geosciences, 51, 193–205, doi: 10.1016/j.cageo.2012.07.021.
Chen, K. H., and R. Bürgmann (2017), Creeping faults: Good news, bad news?, Reviews of Geophysics, 55, 282–286, doi: 10.1002/2017RG000565.
Chester, F. M., and J. S. Chester (1998), Ultracataclasite structure and friction processes of the Punchbowl fault, San Andreas system, California, Tectonophysics, 295(1), 199–221, doi: 10.1016/S0040-1951(98)00121-8.
Chester, F. M., and J. M. Logan (1986), Implications for mechanical properties of brittle faults from observations of the Punchbowl fault zone, California, Pure and Applied Geophysics, 124(1), 79–106, doi: 10.1007/BF00875720.
Chester, F. M., J. P. Evans, and R. L. Biegel (1993), Internal structure and weakening mechanisms of the San Andreas Fault, Journal of Geophysical Research, [Solid Earth], 98(B1), 771–786, doi: 10.1029/92JB01866.
d’Alessio, M. A. (2004), The thermal and mechanical behavior of faults, Ph.D. thesis, University of California, Berkeley, Ann Arbor, United States.
Dibblee, T. W., Jr, and B. Carter (2002), Geologic Map of the Condor Peak Quadrangle, Los Angeles, CA, Tech. rep., Dibblee Foundation.
Dibblee, T. W., Jr, and H. E. Ehrenspeck (1991a), Geologic Map of the Sunland and North Burbank Quadrangles, Los Angeles, CA, Tech. rep., Dibblee Foundation.
Dibblee, T. W., Jr, and H. E. Ehrenspeck (1991b), Geologic map of the San Fernando and Van Nuys (north half) quadrangles, Los Angeles County, California, Tech. rep., Dibblee Foundation.
Dolan, J. F., and B. D. Haravitch (2014), How well do surface slip measurements track slip at depth in large strike-slip earthquakes? the importance of fault structural maturity in controlling on-fault slip versus off-fault surface deformation, Earth and planetary science letters, 388, 38–47, doi: 10.1016/j.epsl.2013.11.043.
Duan, Q., X. Yang, S. Ma, J. Chen, and J. Chen (2016), Fluid–rock interactions in seismic faults: Implications from the structures and mineralogical and geochemical compositions of drilling cores from the rupture of the 2008 Wenchuan earthquake, China, Tectonophysics, 666, 260–280, doi: 10.1016/j.tecto.2015.11.008.
Ehlig, P. L. (1973), History, seismicity and engineering geology of the san gabriel fault, in Geology, seismicity, and environmental impact, pp. 247–251, Association of Engineering Geologist.
Evans, J. P. (1990), Textures, deformation mechanisms, and the role of fluids in the cataclastic deformation of granitic rocks, in Deformation Mechanisms, Rheology, and Tectonics, pp. 29–39, Geological Society, London, Special Publications 54, doi: 10.1144/GSL.SP.1990.054.01.03.
Evans, J. P., and F. M. Chester (1995), Fluid-rock interaction in faults of the San Andreas system: Inferences from San Gabriel fault rock geochemistry and microstructures, Journal of Geophysical Research, 100(B7), 13,007–13,020, doi: 10.1029/94jb02625.
Evans, J. P., K. Crouch, C. Studnicky, S. Bone, N. Edwards, and S. Webb (2023), Fluid-rock interactions, hydrothermal processes, and accommodation of slip in shallow parts of the San Andreas and San Gabriel Faults, southern California, doi: 10.31223/X5X096.
Faulkner, D. R., A. C. Lewis, and E. H. Rutter (2003), On the internal structure and mechanics of large strike-slip fault zones: field observations of the Carboneras fault in southeastern Spain, Tectonophysics, 367(3), 235–251, doi: 10.1016/S0040-1951(03)00134-3.
Ferrill, D. A., A. P. Morris, M. A. Evans, M. Burkhard, R. H. Groshong, and C. M. Onasch (2004), Calcite twin morphology: a low-temperature deformation geothermometer, Journal of Structural Geology, 26(8), 1521–1529, doi: 10.1016/j.jsg.2003.11.028.
Forand, D., J. P. Evans, S. U. Janecke, and J. Jacobs (2018), Insights into fault processes and the geometry of the San Andreas fault system: Analysis of core from the deep drill hole at Cajon Pass, California, GSA Bulletin, 130(1-2), 64–92, doi: 10.1130/B31681.1.
Gratier, J.-P., P. Favreau, and F. Renard (2003), Modeling fluid transfer along California faults when integrating pressure solution crack sealing and compaction processes, Journal of Geophysical Research, 108, 2104, doi: 10.1029/2001JB000380.
Haines, S. H., B. A. van der Pluijm, M. Ikari, D. Saffer, and C. Marone (2009), Clay fabric intensity in natural and artificial fault gouges: Implications for brittle fault zone processes and sedimentary basin clay fabric evolution, Journal of Geophysical Research, 114, B05,406, doi: 10.1029/2008JB005866.
Hauksson, E., and M.-A. Meier (2019), Applying Depth Distribution of Seismicity to Determine Thermo-Mechanical Properties of the Seismogenic Crust in Southern California: Comparing Lithotectonic Blocks, Pure and Applied Geophysics, 176(3), 1061–1081, doi: 10.1007/s00024-018-1981-z.
Holdsworth, R. E., E. W. E. van Diggelen, C. J. Spiers, J. H. P. de Bresser, R. J. Walker, and L. Bowen (2011), Fault rocks from the SAFOD core samples: Implications for weakening at shallow depths along the San Andreas Fault, California, Journal of Structural Geology, 33(2), 132–144, doi: 10.1016/j.jsg.2010.11.010.
HSR (2019), Palmdale to Burbank Project Section, Preliminary Geotechnical Data Report for Tunnel Feasibility, Angeles National Forest, Tech. rep., California High-Speed Rail Authority.
Huang, Y., J.-P. Ampuero, and D. V. Helmberger (2014), Earthquake ruptures modulated by waves in damaged fault zones, Journal of Geophysical Research, [Solid Earth], 119(4), 3133–3154, doi: 10.1002/2013jb010724.
Ishikawa, T., M. Tanimizu, K. Nagaishi, J. Matsuoka, O. Tadai, M. Sakaguchi, T. Hirono, T. Mishima, W. Tanikawa, W. Lin, H. Kikuta, W. Soh, and S.-R. Song (2008), Coseismic fluid–rock interactions at high temperatures in the Chelungpu fault, Nature Geoscience, 1(10), 679–683, doi: 10.1038/ngeo308.
Ishikawa, T., T. Hirono, N. Matsuta, K. Kawamoto, K. Fujimoto, J. Kameda, Y. Nishio, Y. Maekawa, and G. Honda (2014), Geochemical and mineralogical characteristics of fault gouge in the Median Tectonic Line, Japan: evidence for earthquake slip, Earth, Planets and Space, 66(1), 1–20, doi: 10.1186/1880-5981-66-36.
Jefferies, S. P., R. E. Holdsworth, C. A. J. Wibberley, T. Shimamoto, C. J. Spiers, A. R. Niemeijer, and G. E. Lloyd (2006), The nature and importance of phyllonite development in crustal-scale fault cores: an example from the Median Tectonic Line, Japan, Journal of Structural Geology, 28(2), 220–235, doi: 10.1016/j.jsg.2005.10.008.
Jennings, C. W., and R. G. Strand (1969), Los Angeles Geologic Map, 1:250,000.
Kaneko, Y., and Y. Fialko (2011), Shallow slip deficit due to large strike-slip earthquakes in dynamic rupture simulations with elasto-plastic off-fault response, Geophysical Journal International, 186(3), 1389–1403, doi: 10.1111/j.1365-246X.2011.05117.x.
Lee, H. K., and H. P. Schwarcz (1996), Electron spin resonance plateau dating of periodicity of activity on the San Gabriel fault zone, southern California, Geological Society of America bulletin, 108, 735–746.
Marchandon, M., J. Hollingsworth, and M. Radiguet (2021), Origin of the shallow slip deficit on a strike slip fault: Influence of elastic structure, topography, data coverage, and noise, Earth and Planetary Science Letters, 554, 116,696, doi: 10.1016/j.epsl.2020.116696.
Marone, C., and D. M. Saffer (2007), 12. Fault Friction and the Upper Transition from Seismic to Aseismic Faulting, in The Seismogenic Zone of Subduction Thrust Faults, edited by T. H. Dixon and J. C. Moore, pp. 346–369, Columbia University Press, doi: 10.7312/dixo13866-012.
Mitchell, T. M., and D. R. Faulkner (2009), The nature and origin of off-fault damage surrounding strike-slip fault zones with a wide range of displacements: A field study from the Atacama fault system, northern Chile, Journal of Structural Geology, 31(8), 802–816, doi: 10.1016/j.jsg.2009.05.002.
Nevitt, J. M., B. A. Brooks, R. D. Catchings, M. R. Goldman, T. L. Ericksen, and C. L. Glennie (2020), Mechanics of near-field deformation during co- and post-seismic shallow fault slip, Scientific Reports, 10(1), 5031, doi: 10.1038/s41598-020-61400-9.
Nourse, J. A. (2002), Middle Miocene reconstruction of the central and eastern San Gabriel Mountains, southern California, with implications for evolution of the San Gabriel fault and Los Angeles basin, Geological Society of America Special Paper, 365, 161–185, doi: 10.1130/0-8137-2365-5.161.
Ohtani, T., K. Fujimoto, H. Ito, H. Tanaka, N. Tomida, and T. Higuchi (2000), Fault rocks and past to recent fluid characteristics from the borehole survey of the Nojima fault ruptured in the 1995 Kobe earthquake, southwest Japan, Journal of Geophysical Research, 105(B7), 16,161–16,171, doi: 10.1029/2000jb900086.
Powell, R. E. (1993), Chapter 1: Balanced palinspastic reconstruction of pre-late Cenozoic paleogeology, southern California: Geologic and kinematic constraints on evolution of the San Andreas fault system, in Geological Society of America Memoirs, edited by R. E. Powell and E. al., Memoir - Geological Society of America, pp. 1–106, Geological Society of America, doi: 10.1130/mem178-p1.
Roten, D., K. B. Olsen, and S. M. Day (2017a), Off-fault deformations and shallow slip deficit from dynamic rupture simulations with fault zone plasticity, Geophysical Research Letters, 44(15), 7733–7742, doi: 10.1002/2017gl074323.
Roten, D., K. B. Olsen, S. M. Day, and Y. Cui (2017b), Quantification of fault-zone plasticity effects with spontaneous rupture simulations, Pure and Applied Geophysics, 174, 3369–3391, doi: 10.1007/s00024-017-1466-6.
Rowe, K. J., and E. H. Rutter (1990), Palaeostress estimation using calcite twinning: experimental calibration and application to nature, Journal of Structural Geology, 12(1), 1–17, doi: 10.1016/0191-8141(90)90044-Y.
Rutter, E. H. (1986), On the nomenclature of the mode of failure, transitions in rocks, Tectonophysics, 122, 381–387.
Rutter, E. H., D. R. Faulkner, and R. Burgess (2012), Structure and geological history of the Carboneras Fault Zone, SE Spain: Part of a stretching transform fault system, Journal of Structural Geology, 45, 68–86, doi: 10.1016/j.jsg.2012.08.009.
Schleicher, A. M., S. N. Tourscher, B. A. van der Pluijm, and L. N. Warr (2009), Constraints on mineralization, fluid-rock interaction, and mass transfer during faulting at 2-3 km depth from the SAFOD drill hole, Journal of Geophysical Research, [Solid Earth], 114(B04202), doi: 10.1029/2008JB006092.
Schleicher, A. M., B. A. van der Pluijm, and L. N. Warr (2012), Chlorite-smectite clay minerals and fault behavior: New evidence from the San Andreas Fault Observatory at Depth (SAFOD) core, Lithosphere, 4(3), 209–220, doi: 10.1130/L158.1.
Scholz, C. H. (1988), The brittle-plastic transition and the depth of seismic faulting, Geologische Rundschau: Zeitschrift fur allgemeine Geologie, 77(1), 319–328, doi: 10.1007/BF01848693.
Scholz, C. H. (2019), The Mechanics of Earthquakes and Faulting, 3rd ed., 493 pp., Cambridge University Press.
Schulz, S. E., and J. P. Evans (1998), Spatial variability in microscopic deformation and composition of the Punchbowl fault, southern California: implications for mechanisms, fluid–rock interaction, and fault morphology, Tectonophysics, 295(1), 223–244, doi: 10.1016/S0040-1951(98)00122-X.
Schulz, S. E., and J. P. Evans (2000), Mesoscopic structure of the Punchbowl Fault, Southern California and the geologic and geophysical structure of active strike-slip faults, Journal of Structural Geology, 22(7), 913–930, doi: 10.1016/S0191-8141(00)00019-5.
Scott, C., J. Champenois, Y. Klinger, E. Nissen, T. Maruyama, T. Chiba, and R. Arrowsmith (2019), The 2016 M7 Kumamoto, japan, earthquake slip field derived from a joint inversion of differential lidar topography, optical correlation, and InSAR surface displacements, Geophysical Research Letters, 46, 6341–6351, doi: 10.1029/2019GL083785.
Shinevar, W. J., M. D. Behn, G. Hirth, and O. Jagoutz (2018), Inferring crustal viscosity from seismic velocity: Application to the lower crust of Southern California, Earth and Planetary Science Letters, 494, 83–91, doi: 10.1016/j.epsl.2018.04.055.
Sibson, R. H. (1977), Fault rocks and fault mechanisms, https://www.lyellcollection.org/doi/10.1144/gsjgs.133. 3.0191, doi: 10.1144/gsjgs.133.3.0191, accessed: 2023-9-15.
Song, S.-R., L.-W. Kuo, E.-C. Yeh, C.-Y. Wang, J.-H. Hung, and K.-F. Ma (2007), Characteristics of the lithology, fault-related rocks and fault zone structures in TCDP hole-A, TAO: Terrestrial, Atmospheric and Oceanic Sciences, 18(2), 243, doi: 10.3319/tao.2007.18.2.243(tcdp).
Studnicky, C. (2021), Constraining Deformation Mechanisms of Fault Damage Zones: A Case Study of the Shallow San Andreas Fault at Elizabeth Lake, Southern California, Master’s thesis, Utah State University, doi: 10.26076/638e-3616.
Sutherland, R., V. G. Toy, J. Townend, S. C. Cox, J. D. Eccles, D. R. Faulkner, D. J. Prior, R. J. Norris, E. Mariani, C. Boulton, B. M. Carpenter, C. D. Menzies, T. A. Little, M. Hasting, G. P. De Pascale, R. M. Langridge, H. R. Scott, Z. Reid Lindroos, B. Fleming, and A. J. Kopf (2012), Drilling reveals fluid control on architecture and rupture of the Alpine fault, New Zealand, Geology, 40(12), 1143–1146, doi: 10.1130/G33614.1.
Thakur, P., Y. Huang, and Y. Kaneko (2020), Effects of low-velocity fault damage zones on long-term earthquake behaviors on mature strike-slip faults, Journal of Geophysical Research, [Solid Earth], 125(8), e2020JB019,587, doi: 10.1029/2020jb019587.
Wang, K. (2021), If Not Brittle: Ductile, Plastic, or Viscous?, Seismological Research Letters, 92(2A), 1181–1184, doi: 10.1785/0220200242.
Warr, L. N., and S. S. Cox (2001), Clay mineral transformations and weakening mechanisms along the Alpine Fault, New Zealand, https://www. lyellcollection.org/doi/10.1144/GSL.SP.2001.186.01.06, doi: 10.1144/GSL.SP.2001.186.01.06, accessed: 2023-9-15.
Weber, F. H. (1982), Geology and geomorphology along the San Gabriel fault zone, Los Angeles and Ventura counties, California, Tech. rep., Div. Mines and Geology Open File Report.
Wibberley, C. A. J., and T. Shimamoto (2003), Internal structure and permeability of major strike-slip fault zones: the Median Tectonic Line in Mie Prefecture, Southwest Japan, Journal of Structural Geology, 25(1), 59–78, doi: 10.1016/S0191-8141(02)00014-7.
Wibberley, C. A. J., G. Yielding, and G. Di Toro (2008), Recent advances in the understanding of fault zone internal structure; a review, Structure of Fault Zones: Implications for Mechanical and Fluid-flow Properties, Geological Society of London Special Publication, 299, 5–33, doi: 10.1144/SP299.2 0305-8719/08.
Williams, C. F., and J. DeAngelo (2011), Evaluation of approaches and associated uncertainties in the estimation of temperatures in the upper crust of the Western United States, GRC Transactions, 35, 1599–1605.
Williams, R. T., C. D. Rowe, K. Okamoto, H. M. Savage, and E. Eves (2021), How fault rocks form and evolve in the shallow San Andreas fault, Geochemistry, Geophysics, Geosystems, 22(11), e2021GC010,092, doi: 10.1029/2021gc010092.
Woodcock, N. H., and K. Mort (2008), Classification of fault breccias and related fault rocks, Geological Magazine, 145(3), 435–440, doi: 10.1017/S0016756808004883.
Yeats, R. S., G. J. Huftile, and L. T. Stitt (1994), Late Cenozoic Tectonics of the East Ventura Basin, Transverse Ranges, California1, AAPG Bulletin, 78(7), 1040–1074, doi: 10.1306/A25FE42D-171B-11D7-8645000102C1865D.
Yerkes, R. F., and R. H. Campbell (2005), Preliminary Geologic Map of the Los Angeles 30’ x 60’ Quadrangle, Southern California, version 2.1, 1:100000 scale, U. S. Geological Survey Open-file Report.
Zoback, M., S. Hickman, and W. Ellsworth (2010), Scientific drilling into the San Andreas fault zone, Eos, 91(22), 197–199, doi: 10.1029/2010eo220001.