Skip to main content

Advertisement

Preliminary report on the Sanyi-Puli seismic zone conductivity anomaly and its correlation with velocity structure and seismicity in the Northwestern Taiwan

Article metrics

  • 220 Accesses

  • 6 Citations

Abstract

As part of seismotectonic investigations in Northwestern Taiwan, eight magnetotelluric (MT) soundings were conducted across the Sanyi-Puli seismic zone, a distinct NW-SE trending linear seismic zone in the fold-thrust belt of Northwestern Taiwan. A preliminary one-dimensional resistivity model according to the determinant MT response was computed, and the resistivity model includes a high-conductivity anomaly beneath this seismic zone. This conductivity anomaly raises the possibility of metamorphic dehydration triggering the seismic events in the seismic zone. The correlation between the conductivity anomaly and active seismicity in this area is tentatively discussed in this study.

References

  1. Ague, J. J., J. Park, and D. M. Rye, Regional metamorphic dehydration and seismic hazard, Geophys. Res. Lett., 25, 4221–4224, 1998.

  2. Bailey, R. C., Trapping of aqueous fluids in the deep crust, Geophys. Res. Lett., 17, 1129–1132, 1990.

  3. Chen, C. H. and C. H. Wang, Explanatory notes for the metamorphic facies map of Taiwan, Second Edition, 51 pp., Central Geological Survey, MOEA, Taipei, Taiwan, 1995 (in Chinese).

  4. Deffontaines, B., J. C. Lee, J. Angelier, J. Carvalho, and J. P. Rudant, New geomorphic data on the active Taiwan orogen: A multisource approach, J. Geophys. Res., 99, 20,243–20,266, 1994.

  5. Groom, R. W. and R. C. Bailey, Decomposition of magnetotelluric impedance tensor in the presence of local three-dimensional galvanic distortion, J. Geophys. Res., 94, 1913–1925, 1989.

  6. Gudmundsson, A., Fluid overpressure and stress drop in fault zones, Geophys. Res. Lett., 26, 115–118, 1999.

  7. Hsu, C. H., C. I. Lee, and J. F. Lee, NW-SE trending seismic zone in the Miaoli-Taichung-Nantou area, Central Taiwan, and its implication in tectonics, in Proceedings of The Sixth Symposium on Taiwan Quaternary, pp. 224–228, 1996 (in Chinese).

  8. Ingham, M. R., The use of invariant impedances in magnetotelluric interpretation, Geophys. J. Int., 92, 165–169, 1988.

  9. 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, pp. 81–143, Elsevier, New York, 1992.

  10. Lee, S. J., The S-wave velocity structure under central-western Taiwan by strong ground motion waveform modeling, M Sc. thesis, Nat. Central Univ., 138 pp., Chungli, Taiwan, 1999 (in Chinese).

  11. Lin, C. H. and S. W. Roecker, Deep earthquakes beneath central Taiwan: mantle shearing in an arc-continent collision, Tectonics, 12, 745–755, 1993.

  12. Oldenburg, D. W. and R. G. Ellis, Efficient inversion of magnetotelluric data in two dimensions, Phys. Earth Planet. Inter., 81, 177–200, 1993.

  13. Pellerin, L. and G. W. Hohmann, Transient electromagnetic inversion: A remedy for magnetotelluric static shifts, Geophysics, 55, 1242–1250, 1990.

  14. Ranganayaki, R. P., The interpretive analysis of magnetotelluric data, Geophysics, 49, 1730–1748, 1984.

  15. Rau, R. J., J. C. Lee, H. Kao, and H. T. Chu, Transition from convergence to escape: inferences from seismic tomography, seismicity, and focal mechanisms in the foreland belt of central-western Taiwan, J. Geophys. Res., 1998 (submitted).

  16. Seno, T., S. Stein, and A. E. Gripp, A model for the motion of the Philippine Sea plate consistent with NUVEL-1 and geological data, J. Geophys. Res., 98, 17,941–17,948, 1993.

  17. Suppe, J., Mechanics of mountain building and metamorphism in Taiwan, Mem. Geol. Soc. China, 4, 67–89, 1981.

  18. Suppe, J. and J. H. Wittke, Abnormal pore-fluid pressures in relation to stratigraphy and structure in the active fold-and-thrust belt of northwestern Taiwan, Petrol. Geol. Taiwan, 14, 11–24, 1977.

Download references

Author information

Correspondence to Chien-chih Chen.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Chen, C., Chen, C. Preliminary report on the Sanyi-Puli seismic zone conductivity anomaly and its correlation with velocity structure and seismicity in the Northwestern Taiwan. Earth Planet Sp 52, 377–381 (2000) doi:10.1186/BF03351649

Download citation

Keywords

  • Apparent Resistivity
  • Seismic Zone
  • Magnetotelluric Data
  • Western Foothill
  • Conrad Discontinuity