Abstract
On August 17, 1999, a destructive earthquake occurred in the western part of the North Anatolian Fault Zone, Turkey. The earthquake source region has been designated as a seismic gap and an M7-class earthquake has been supposed to occur someday in the future so as to fill this seismic gap. So far we have undertaken various kinds of observations in this area and we could obtain some valuable data before, during and after the mainshock. Here we report some of the preliminary results of our recent studies, which include field work started in late July this year and continued during and after the earthquake occurrence just in the earthquake source region and its vicinity, in addition to seismic observations carried out for several years before the mainshock. Much emphasis is put on magnetotelluric field data acquired during the mainshock; in fact, large variations caused by seismic waves were recorded. Such variations could be interpreted in terms of electromagnetic induction in the conducting crust caused by the velocity field interacting with the static magnetic field of the Earth. In particular, the first motion of seismic wave could be identified in the records and used for precise determination of the hypocenter of the mainshock.
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References
Aki, K., Characterization of barriers on an earthquake fault, J. Geophys. Res., 84, 6140–6148, 1979.
Allen, C. R., Comparisons between the North Anatolian fault of Turkey and the San Andreas fault, California, In Multidisciplinary Approach to Earthquake Predicition, Edited by A. M. Işikara and A. Vogel, Friedr. Vieweg & Sohn, Braunschweig, 67–75, 1982.
Ambraseys, N. N. and A. Zatopek, The Mudurnu valley, west Anatolia, Turkey, earthquakeof 22 July 1967, Bull. Seism. Soc. Am., 59, 521–589, 1969.
Barka, A. A., The North Anatolian Fault Zone, Annales Tectonicae, 6, 164–195, 1992.
Barka, A. A., Neotectonics of the Marmara region, in Active Tectonics of Northwestern Anatolia — The MARMARA Poly-Project, Edited by C. Schindler and M. Pfisters, Hochschulverlag AG an der ETH, Zurich, pp. 55–87, 1997.
Crampin, S., R. Evans, and S. B. Üçer, Analysis of local earthquakes: the Turkish Dilatancy Projects (TDP1 and TDP 2), Geophys. J. R. astr. Soc, 83, 1–16, 1985.
Evans, R., I. Asudeh, S. Crampin, and S. B. Üçer, Tectonics of the Marmara sea region of Turkey: new evidence from micro-earthquake fault plane solution, Geophys. J. R. astr. Soc, 83, 47–60, 1985.
Evans, R., D. Beamish, S. Crampin, and S. B. Üçer, Turkish Dilatancy Project (TDP3): multidisciplinary studies ofapotential earthquake source region, Geophys. J. R. astr. Soc, 91, 265–286, 1987.
Gamble, T. D., W. M. Goubau, and J. Clarke, Magnetotellurics with a remote reference, Geophysics, 44, 53–68, 1979.
Honkura, Y. and A. M. Işikara, Multidisciplinary research on fault activity in the western part of the North Anatolian Fault Zone, Tectonophys., 193, 347–357, 1991.
Honkura, Y, A. M. Işikara, D. Kolcak, N. Orbay, S. Sipahioglu, N. Ohshiman, and H. Tanaka, Magnetic anomalies and low ground resistivity as possible indicators of active fault location: preliminary results of electric and magnetic observations from the western part of the North Anatolian Fault Zone, J. Geomag. Geoelectr, 37, 169–187, 1985.
Iio, Y., C. Gürbüz, K. Nishigami, A. Pinar, N. Aybey, S. B. Üçer, Y. Honkura, and A. M. Isikara, Microseismic activity around the western extension of the 1967 Mudurnu earthquake fault, Tectonophys., 193, 327–334, 1991.
Ikeda, Y., Geomorphological observations of the North Anatolian Fault Zone west of Mudurnu, In Multidisciplinary Research on Fault Activity in the Western Part of the North Anatolian Fault Zone, Edited by Y Honkura and A. M. Işikara, 6–14, 1988.
Kanamori, H., The nature of seismicity patterns before large earthquakes, In Earthquake Prediction — An International Review, Edited by D. W. Simpson and P. G. Richards, Am. Geophys. Union, Washington, 1–19, 1981.
Lovell, J. H., S. Crampin, R. Evans, and S. B. Üçer, Micro-earthquakes in TDP swarm, Turkey; clustering in space and time, Geophys. J. R. astr. Soc, 91, 313–330, 1989.
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.
Mogi, K., Sequential occurrences of recent great earthquakes, J. Phys. Earth, 16, 30–36, 1968.
Nishigami, K., Y. Iio, C. Gürbüz, A. Pinar, N. Aybey, S. B. Üçer, Y. Honkura, and A. M. Isikara, Microseismic activity and spatial distribution of coda-Q in westernmost part of the North Anatolian Fault Zone, Turkey, Bull. Dis. Prev. Res. Inst. Kyoto Univ., 40, 41–56, 1990.
Ogawa, Y. and Y. Honkura, An audiomagnetotelluric view of the Atera fault, J. Geomag. Geoelectr, 49, 1065–1071, 1997.
Ogawa, Y. and T. Uchida, A two-dimensional magnetotelluric inversion assuming Gaussian static shift, Geophys. J. Int., 126, 69–76, 1996.
Stein, R. S., A. Barka, and J. H. Dieterich, Progressive failure of the North Anatolian fault since 1939 by earthquake stress triggering, Geophys. J. Int., 128, 594–604, 1997.
Straub, C. and H.-G. Kahle, GPS and geologic estimates of the tectonic activity in the Marmara Sea region, NW Anatolia, J. Geophys. Res., 102, 27587–27601, 1997.
Sykes, L. R., Aftershock zones of great earthquakes, seismicity gaps, and earthquake prediction for Alaska and the Aleutians, J. Geophys. Res., 76, 8021–8041, 1971.
Toksöz, M. N., A. F. Shakal, and A. J. Michael, Space-time migration of earthquakes along the North Anatolian Fault Zone and seismic gaps, Pure Appl. Geophys., 117, 1258–1270, 1979.
Tsukuda, T., K. Satake, Y. Honkura, S. B. Üçer, and A. M. Işikara, Low seismicity, low coda-Q and discontinuities of the upper crust in the vicinity of the Iznik-Mekece fault, the North Anatolian Fault Zone, Turkey, Bull. Earthq. Res. Inst. Univ. Tokyo, 63, 327–348, 1988.
Tunçer, M. K., Y. Honkura, N. Oshiman, Y. Ikeda, and A. M. Işikara, Magnetic anomalies related to active folds in the North Anatolian Fault Zone, J. Geomag. Geoelectr, 43, 813–823, 1991.
Üçer, S. B., S. Crampin, R. Evans, and N. Kafadar, The MARNET radio linked seismometer network spanning the Marmara Sea and the seismicity of western Turkey, Geophys. J. R. astr. Soc, 83, 17–30, 1985.
Uchida, T., Smooth 2-D inversion for magnetotelluric data based on statistical criterion ABIC, J. Geomag. Geoelectr, 45, 841–858, 1993.
Unsworth, M., G. Egbert, and J. Booker, High-resolution electromagnetic imaging of the San Andreas fault in Central California, J. Geophys. Res., 104, 1131–1150, 1999.
Unsworth, M. J., P. E. Malin, G. D. Egbert, and J. R. Booker, Internal structure of the San Andreas Fault Zone at Parkfield California, Geology, 25, 359–362, 1997.
Yagi, Y. and M. Kikuchi, Source process of 17 August 1999 Turkey earthquake, Programme and Abstracts, Seismol. Soc. Japan 1999 Fall Meeting, A70, 1999.
Zhao, D. and H. Negishi, The 1995 Kobe earthquake: seismic image of the source zone and its implications for the rupture nucleation, J. Geophys. Res., 103, 9967–9986, 1998.
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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Honkura, Y., Işikara, A.M., Oshiman, N. et al. Preliminary results of multidisciplinary observations before, during and after the Kocaeli (Izmit) earthquake in the western part of the North Anatolian Fault Zone. Earth Planet Sp 52, 293–298 (2000). https://doi.org/10.1186/BF03351638
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DOI: https://doi.org/10.1186/BF03351638