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Volume 54 Supplement 11

Special Issue: Slip and Flow Processes in and below the Seismogenic Region

Structure and strength of a continental transform from onshore-offshore seismic profiling of South Island, New Zealand

Abstract

Seismic images of deformation beneath South Island, New Zealand, are provided by a form of seismic exploration uniquely suited to the study of “continental islands”—double-sided, onshore-offshore seismic methods in conjunction with onshore refraction and teleseismic P-wave delay data. Four sets of independent observations and analysis are use to infer rock properties within this plate boundary zone: seismic and electrical indications of high-fluid pressures within the crust; P-wave delays from teleseismic anisotropy to show a high-speed zone in the mantle directly below the crustal root; Pn anisotropy of 11±3% distributed over a region > 100 km-wide; and an effective elastic thickness (Te) that is vanishingly small beneath the Southern Alps and surface outcrop of the Alpine Fault, but increases to values of Te > 20 km beyond the coastlines of the South Island. Together, these observations show that deformation in the crust and mantle becomes progressively wider with depth. A region of distributed deformation > 200 km wide is inferred for the upper mantle. We propose that the weakness and the wide zone of deformation are phenomena of plate boundaries where both strike-slip and convergence have persisted for several millions of years.

References

  • Anderson, H. and T. H. Webb, New Zealand seismicity patterns revealed by the upgraded National Seismic Network, N.Z. J. Geol. and Geophys., 37, 477–493, 1994.

    Article  Google Scholar 

  • Beaumont, C., P. J. J. Kamp, J. Hamilton, and P. Fullsack, The continental collision zone, South Island, New Zealand; comparison of geodynamical models and observations, J. Geophys. Res., 100, 3333–3359, 1996.

    Article  Google Scholar 

  • Beavan, J., M. Moore, C. Pearson, M. Henderson, B. Parsons, S. Bourne, P. England, D. Walcott, G. Blick, D. Darby, and K. Hodgkinson, Crustal deformation during 1994–1998 due to oblique continental collision in the central Southern Alps, New Zealand, and implications for seismic potential of the Alpine Fault, J. Geophys. Res., 104, 25,233–25,255, 1999.

    Article  Google Scholar 

  • Bodine, J. H., M. S. Steckler, and A. B. Watts, Observations of flexure and rheology of the oceanic lithosphere, J. Geophys. Res., 86, 3695–3707, 1981.

    Article  Google Scholar 

  • Burgmann, R., M. G. Kogan, V. E. Levin, C. H. Scholz, R. W. King, and G. M. Steblov, Rapid seismic moment release following the 5 December, 1997 Kronotsky, Kamchatka, earthquake, Geophys. Res. Lett., 28, 1331–1334, 2001.

    Article  Google Scholar 

  • Davey, F. J., T. Henyey, S. Holbrook, D. Okaya, T. Stern, A. Melhuish, S. Henrys, H. Anderson, D. Eberhart-Phillips, T. McEvilly, R. Urhammer, F. Wu, G. Jiracek, P. Wannamaker, G. Caldwell, and N. Christensen, Preliminary results from a geophysical study across a modern, continent-continent collisional plate boundary—the Southern Alps, New Zealand, Tectonophys., 228, 221–236, 1997.

    Google Scholar 

  • Gair, H. S., Sheet 20 - Mt Cook. Geological map of New Zealand, 1:250,000, Department of Scientific and Industrial Research, Wellington, 1967.

    Google Scholar 

  • Hatherton, T., Through the looking glass: a comparative study of New Zealand and California, Nature, 220, 660–663, 1968.

    Article  Google Scholar 

  • Heki, K., S. Miyazaki, and T. Hiromichi, Silent fault slip following an interplate thrust earthquake at the Japan trench, Nature, 386, 595–597, 1997.

    Article  Google Scholar 

  • Holt, W. E. and T. A. Stern, Sediment loading on the Western Platform of the New Zealand continent: Implications for the strength of a continental margin, Earth Planet. Sci. Lett., 107, 523–538, 1991.

    Article  Google Scholar 

  • Hubbert, M. K. and W. W. Rubey, Role of Fluid pressure in mechanics of overthrust faulting, Bull. Geol. Soc. Am., 70, 115–166, 1959.

    Article  Google Scholar 

  • Ismail, W. B. and D. Mainprice, An olivine fabric database: an overview of upper mantle fabrics and seismic anisotropy, Tectonophys., 296, 145–157, 1998.

    Article  Google Scholar 

  • Jones, T. D. and A. Nur, The nature of seismic reflections from deep crustal fault zones, J. Geophys. Res., 89, 3153–3171, 1984.

    Article  Google Scholar 

  • Kamp, P. J. J. and J. M. Tippett, Dynamics of Pacific Plate crust in the South Island (New Zealand) zone of oblique continent-continent convergence, J. Geophys. Res., 98, 16,105-16,118, 1993.

  • Kanamori, H. and M. Kikuchi, The 1992 Nicaragua earthquake: a slow tsumami earthquake associated with subducted sediments, Nature, 361, 714–716, 1993.

    Article  Google Scholar 

  • Kennett, B. L. N. and E. R. Engdahl, Travel times for global earthquake location and phase identification, Geophys. J. Int., 105, 429–465, 1991.

    Article  Google Scholar 

  • Kleffmann, S., F. Davey, A. Melhuish, D. Okaya, and T. Stern, Crustal structure in the central South Island from the Lake Pukaki seismic experiment, N. Z. J. Geol. and Geophys., 41, 39–49, 1998.

    Article  Google Scholar 

  • Klosko, E. R., F. T. Wu, H. J. Anderson, D. Eberhardt-Phillips, T. V. McEvilly, E. Audoine, and M. K. Savage, Upper mantle anisotropy in the New Zealand region, Geophys. Res. Lett., 26, 1497–1500, 1999.

    Article  Google Scholar 

  • Koons, P. O., Two-sided orogen; collision and erosion from the sandbox to the Southern Alps, New Zealand, Geology, 18, 679–682, 1990.

    Article  Google Scholar 

  • Koons, P. O., Three-dimensional critical wedges: Tectonics and topography in oblique collisional orogens, J. Geophys. Res., 99, 12,301–12,315, 1993.

    Article  Google Scholar 

  • Lachenbruch, A. H. and J. H. Sass, Heat flow and energetics of the San Andreas fault zone, J. Geophys. Res., 85, 6185–6222, 1980.

    Article  Google Scholar 

  • Leitner, B., D. Eberhart-Phillips, H. Anderson, and J. Nableck, A focussed look at the Alpine fault, New Zealand: seismicity, focal mechanisms, and stress observations, J. Geophys. Res., 106, 2193–2220, 2001.

    Article  Google Scholar 

  • Miller, S. A., Earthquake scaling and the strength of seismogenic faults; can pore pressures be inferred from earthquake rupture properties?, Proceeding of Int. Symp. on Slip and Flow processes in and below the Seismogenic Zone, Sendai City, Japan, November 2001, Published by Ministry of Education, Culture, Sports, Science and Technology, Japan, 2001.

    Google Scholar 

  • Molnar, P., H. Anderson, E. Audoine, D. Eberhart-Philips, K. Gledhill, E. Klosko, T. McEvilly, D. Okaya, M. Savage, T. Stern, and F. Wu, Continuous deformation versus faulting through the continental lithosphere of New Zealand, Science, 286, 516–619, 1999.

    Article  Google Scholar 

  • Mumme, T. C. and R. I. Walcott, Paleomagnetic studies at Geophysics Division, 1980-813, Department of Scientific and Industrial Research, 1985.

  • Okaya, D., S. Henrys, and T. Stern, Double-sided onshore-offshore seismic imaging of Plate Boundary: Super-gathers across South Island of New Zealand, Tectonophys., 355, 247–263, 2002.

    Article  Google Scholar 

  • Ribe, N. M., On the relation between seismic anisotropy and finite strain, J. Geophys. Res., 97, 8737–8747, 1992.

    Article  Google Scholar 

  • Rice, J. R., Fault stress states, pore pressure distributions, and the weakness of the San Andreas fault, in Fault Mechanics and the Transport Properties of Rocks, edited by B. Evans and T. F. Wong, pp. 475–504, Academic Press, New York, 1992.

    Google Scholar 

  • Rutter, E. H. and K. Brodie, Rheology of the lower crust, in The Lower Continental Crust, Developments in Geotectonics 23, edited by D. M. Fountain, R. Arculus, and R. Kay, pp. 201–268, Elsevier, Amsterdam, 1992.

    Google Scholar 

  • Savage, M. K., Seismic anisotropy and mantle deformation: what have we learned from shear wave splitting studies, Rev. Geophys., 27, 64–106, 1999.

    Google Scholar 

  • Scherwath, M., A. Melhuish, T. Stern, and P. Molnar, Pn anisotropy and distributed upper mantle deformation associated with a continental transform fault, Geophys. Res. Lett., 29, 16–1–16–4, 2002.

    Article  Google Scholar 

  • Scholz, C., Transform fault systems of California and New Zealand: similarities in their tectonic and seismic styles, J. Geol. Soc. Lond., 133, 215–229, 1977.

    Article  Google Scholar 

  • Scholz, C., Evidence for a strong San Andreas fault, Geology, 28, 163–166, 2000.

    Article  Google Scholar 

  • Silver, P. G., Seismic anisotropy beneath the continents: probing the depths of geology, Ann. Rev. Earth Planet. Sci., 24, 385–432, 1996.

    Article  Google Scholar 

  • Smith, E. G. C., T. Stern, and B. O’Brien, A seismic velocity profile across the central South Island, New Zealand, from explosion data., N.Z. J. Geol. and Geophys., 38, 565–570, 1995.

    Article  Google Scholar 

  • Stern, T. A., P. E. Wannamaker, D. Eberhart-Phillips, D. Okaya, and F. J. Davey, Mountain building and active deformation studied in New Zealand, EOS, Transactions, American Geophysical Union, 78, 329,335–336, 1997.

    Google Scholar 

  • Stern, T. A., P. Molnar, D. Okaya, and D. Eberhart-Phillips, Teleseismic P-wave delays and modes of shortening the mantle beneath the South Island, New Zealand, J. Geophys. Res., 105, 21,615–21,632, 2000.

    Article  Google Scholar 

  • Stern, T., S. Kleffmann, D. Okaya, M. Scherwath, and S. Bannister, Low seismic wave-speeds and enhanced fluid pressure beneath the Southern Alps, New Zealand, Geology, 29, 679–682, 2001.

    Article  Google Scholar 

  • Sutherland, R., Cenozoic bending of New Zealand basement terranes and Alpine Fault displacement: a brief review, N.Z. J. Geol. and Geophys., 42, 295–302, 1999.

    Article  Google Scholar 

  • Townend, J. and Z. Zoback, Implications of earthquake focal mechanisms for the frictional strength of the San Andreas fault system, in The Nature and Tectonic Significance of Fault Zone Weakening, edited by R. E. Holdsworth, R. A. Strachan, J. F. Magloughlin, and R. J. Knipe, Special Publication of the Geological Society of London, 186, pp. 13–22, 2001.

  • Walcott, R. I., Plate motion and shear strain rates in the vicinity of the Southern Alps, in The Origin of the Southern Alps, vol. 18, edited by R. I. Walcott and M. M. Cresswell, pp. 5–12, R. Soc. N.Z. Bull., Wellington, 1979.

    Google Scholar 

  • Walcott, R. I., Modes of oblique compression: late Cenozoic tectonics of the South Island of New Zealand, Reviews of Geophysics, 36, 1–26, 1998.

    Article  Google Scholar 

  • Wannamaker, P. E., G. R. Jiracek, J. A. Stodt, T. G. Caldwell, V. M. Gonzalez, J. D. McKnight, and A. D. Porter, Fluid generation and pathways beneath an active compressional orogen, the New Zealand Southern Alps, inferred from magnetotelluric data, EOS Trans. AGU, 79, F903, 1998.

    Google Scholar 

  • Zoback, M., Strength of the San Andreas, Nature, 405, 31, 2000.

    Article  Google Scholar 

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Stern, T., Okaya, D. & Scherwath, M. Structure and strength of a continental transform from onshore-offshore seismic profiling of South Island, New Zealand. Earth Planet Sp 54, 1011–1019 (2002). https://doi.org/10.1186/BF03353294

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Keywords

  • Seismic Anisotropy
  • Mantle Lithosphere
  • Teleseismic Event
  • Alpine Fault
  • Australian Plate