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Resistivity structure in the western part of the fault rupture zone associated with the 1999 İzmit earthquake and its seismogenic implication
Earth, Planets and Space volume 55, pages 437–442 (2003)
Abstract
Magnetotelluric (MT) surveys were carried out along some profiles crossing the fault rupture zone associated with the İzmit earthquake which took place on 17 August 1999 in the western part of the North Anatolian Fault Zone (NAFZ). In this paper, we focus on the western part of the fault rupture zone where two different groups of seismicity followed the İzmit earthquake. One group was seen along a narrow belt and corresponds to aftershocks occurring along the fault rupture zone. The other was seen in a circular region and represents a swarm activity, presumably triggered by the occurrence of the İzmit earthquake. Two-dimensional inversion was performed for the MT data acquired along two profiles; one crosses the western end of the fault rupture zone and the other is located in the west of the swarm activity area. In the former case, aftershocks tended to occur in a resistive zone underlain by a moderately conductive zone, as was the case for the hypocenter area. In the latter case, the swarm activity tends to be confined in a conductive zone below a highly resistive zone. This activity is likely to be triggered through pore-pressure changes associated with the İzmit earthquake.
References
Barış, S., A. Ito, S. B. Üçer, Y. Honkura, N. Kafadar, R. Pektaş, T. Komut, and A. M. Işıkara, Microearthquake activity before the Izmit earthquake in the eastern Marmara region, Turkey (1 January 1993–17 August 1999), Bull. Seismol. Soc. Am., 92, 394–405, 2002.
Bayrak, M. and S. S. Nalbant, Conductive crust imaged in western Turkey by MT, Geophys. Res. Lett., 28(18), 3521–3524, 2001.
Çağlar, I., Electrical resistivity structure of the northwestern Anatolia and its tectonic implications for the Sakarya and Bornova zones, Phys. Earth Planet. Inter., 125, 95–110, 2001.
Eisonlohr, T., The thermal springs of Armutlu peninsula (NW Turkey) and their relationship to geology and tectonic, in Active Tectonics of Northwestern Anatolia: The Marmara Poly-Project, Edited by C. Shindler and M. Pfister, Cambridge Publications, pp. 197–228, 1996.
Gamble, T. D., W. M. Goubau, and J. Clarke, Magnetotellurics with remote magnetic reference, Geophysics, 44, 53–68, 1979.
Groom, R. W. and R. C. Bailey, Decomposition of magnetotelluric impedance tensors in the presence of local three dimensional galvanic distortions, J. Geophys. Res., 94, 1913–1925, 1989. Gürer, A., Deep conductivity structure of the North Anatolian Fault Zone and the Istanbul and Sakarya Zones along the Golpazari-Akcakoca profile, Northwest Anatolia, Int. Geology Review, 38, 727–736, 1996.
Honkura, Y., A. M. Işikara, N. Oshiman, A. Ito, B. Üçer, S. Bariş, M. K. Tunçer, M. Matsushima, R. Pektaş, C. Çelik, S. B. Tank, F. Takahashi, M. Nakanishi, R. Yoshimura, Y. Ikeda and T. Komut, Preliminary results of multidisciplinary observations before, during and after the Kocaeli (Izmit) earthquake in the western part of the North Anatolian Fault Zone, Earth Planets Space, 52, 293–298, 2000.
Ito, A., B. Üçer, S. Barış, A. Nakamura, Y. Honkura, T. Kono, S. Hori, A. Hasegawa, R. Pektaş, T. Komut, and A. M. Işıkara, Aftershock activity of 1999 Izmit earthquake, Turkey, revealed from microearthquake observations, Bull. Seismol. Soc. Am., 92, 418–427, 2002.
Kasaya, T., N. Oshiman, N. Sumitomo, M. Uyeshima, Y. Iio, and D. Uehara, Resistivity structure around the hypocentral are of the 1984 Western Nagano Prefecture earthquake in central Japan, Earth Planets Space, 54, 107–118, 2002.
Mackie, R. L., T. R. Madden, and P. E. Wannamaker, Three-dimensional magnetotelluric modeling using finite difference equations—Theory and comparisons to integral equation solutions, Geophysics, 58, 215–226, 1993.
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, 4371–4374, 2001.
Nesbitt, B. E., Electrical resistivity of crustal fluids, J. Geophys. Res., 98, 4301–4310, 1993.
Ogawa, Y. and T. Uchida, A two-dimensional magnetotelluric inversion assuming Gaussian static shift, Geophys. J. Int., 126, 69–76, 1996.
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, 3741–3744, 2001.
Ogawa, Y., S. Takakura, and Y. Honkura, Resistivity structure across Itoigawa-Shizuoka tectonic line and its implications for concentrated deformation, Earth Planets Space, 54, 1115–1120, 2002.
Oshiman, N., R. Yoshimura, T. Kasaya, Y. Honkura, M. Matsushima, S. Bariş, C. Çelik, M. K. Tunçer, and A. M. Işikara, Deep resistivity structure around the fault associated with the 1999 Kocaeli earthquake, Turkey, in Seismotectonics in Convergent Plate Boundary, edited by Y. Fujinawa and A. Yoshida, pp. 293–303, Terra Sci. Publ. Company, Tokyo, 2002.
Pınar, A., Y. Honkura, and K. Kuge, Seismic activity triggered by the 1999 Izmit earthquake and its implications for the assessment of future seismic risk, Geophys. J. Int., 146, F1–F7, 2001.
Unsworth, M. J., P. A. Bedrosian, M. Eisel, G. D. Egbert, and W. Siripunvaraporn, Along strike variations in the electrical structure of the San Andreas Fault at Parkfield, California, Geophys. Res. Lett., 27, 3021–3024, 2000.
Yagi, Y. and M. Kikuchi, Source rupture process of the Kocaeli, Turkey, earthquake of August 17, 1999, obtained by joint inversion of near-field data and teleseismic data, Geophys. Res. Lett., 27, 1969–1972, 2000.
Yılmaz, Y., S. C. Genç, E. Yigitbaş, M. Bozcu, and K. Yılmaz, Geological evolution of the late Mesozoic continental margin of Northwestern Anatolia, Tectonophysics, 243, 155–171, 1995.
Zhao, D., H. Kanamori, and H. Negishi, Tomography of the source area of the 1995 Kobe earthquake: evidence for fluids at the hypocenter?, Science, 274, 1891–1894, 1996.
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Tank, S.B., Honkura, Y., Ogawa, Y. et al. Resistivity structure in the western part of the fault rupture zone associated with the 1999 İzmit earthquake and its seismogenic implication. Earth Planet Sp 55, 437–442 (2003). https://doi.org/10.1186/BF03351777
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DOI: https://doi.org/10.1186/BF03351777
Key words
- Magnetotellurics
- resistivity structure
- İzmit earthquake
- North Anatolian Fault Zone
- seismogenic zone