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Three-dimensional structure of Vp, Vs and Vp/Vs in the upper crust of the Marmara region, NW Turkey


We applied a 3-D seismic tomography inversion algorithm to arrival-time data obtained, during 18 years from 1985 to 2002, from local seismic networks and aftershock studies in the Marmara region, in order to better understand the upper crustal structure of the complex tectonic region. We integrated all the available data set into a common data set and relocated the events, using a 1-D velocity model. We then selected 3,949 earthquakes and obtained 92355 arrival times, in total, consisting of 59,313 P-wave and 33,042 S-wave arrival times. In this paper we present detailed crustal structures for V p, V s and V p/V s ratios from the surface down to 15 km depth with good resolution in terms of the hit count analysis of seismic rays, the checkerboard and restoring resolution tests for the studied region. The results obtained from the inversion suggest that the western part of the North Anatolian Fault Zone shows strong lateral heterogeneity. We concluded that no clear pattern exists between the distribution of microearthquakes and aftershocks and the velocity perturbations presented in this paper. This is probably due to complex tectonic and geological structures. Large coseismic slip associated with the two recent strong earthquakes was found to correspond to higher velocity anomalies, as was often found recently. On the other hand, low velocity values correspond to the sedimentary units or the alluvium regions, as supported by the low resistivity and gravity values. Thus the results presented in this paper are quite consistent with the other data such as gravity, resistivity and magnetic anomalies, indicating that our model is reliable and efficient and it should be useful for further interpretation of tectonic and geological problems in this region. It should be pointed out, however, that the results of S-wave perturbations and V p/V s ratio could not be discussed in detail because of insufficient quality of the S-wave data and the reliability of the results is not very high. Nonetheless, the fact that recent large Izmit earthquake and moderate aftershocks that occurred in or around the high velocity zones near the low velocity region suggests that high velocity regions found in the area close to Istanbul in the Marmara Sea and also at the Iznik-Mekece fault are potential sites for strain energy accumulation and release.


  1. Adatepe, F., S. Demirel, and B. Alpar, Tectonic setting of the southern Marmara Sea region based on seismic reflection data and gravity modelling, Mar. Geol., 190, 383–395, 2002.

  2. Aki, K. and W. H. K. Lee, Determination of three-dimensional velocity anomalies under a seismic array using first P arrival times from local earthquakes, A homogeneous initial model, J. Geophys. Res., 81, 4381–4399, 1976.

  3. Alpar, B. and C. Yaltirak, Characteristic features of the North Anatolian Fault in the eastern Marmara region and its tectonic evolution, Mar. Geol., 190, 329–350, 2002.

  4. Ambraseys, N. N. and C. F. Finkel, Long-term seismicity of Istanbul and of the Marmara region, Engin. Seis. Earthq. Engin. Report, 91/8, Imperial Collage, 1991.

  5. Ambraseys, N. N. and C. F. Finkel, The Seismicity of Turkey and Adjacent Areas, Eren Yayincilik, Istanbul, Turkey, 1995.

  6. Ateş, A., T. Kayiran, and I. Şençer, Structural interpretation of the Marmara region, NW Turkey, from aeromagnetic, seismic and gravity data, Tectonophysics, 367, 41–99, 2003.

  7. Aydin, A. and D. Kalafat, Surface ruptures of the August and 12 November 1999 Izmit and Duzce earthquakes in northwestern Anatolia, Turkey: their tectonic and kinematic significance and associated damage, Bull. Seism. Soc. Am., 92, 95–106, 2002.

  8. Ayhan, M. E., C. Demir, O. Lenk, A. Kiliçoğlu, Y. Altiner, A. A. Barka, S. Ergintav, and H. Özener, Interseismic strain accumulation in the Marmara Sea region, Bull. Seism. Soc. Am., 92, 216–229, 2002.

  9. Barka, A., The North Anatolian Fault Zone, Ann. Tectonicae, 6, 164–195, 1992.

  10. Barka, A., The 17 August 1999 Izmit earthqauke, Science, 285, 1858–1859, 1999.

  11. Barka, A. A. and K. Kadinsky-Cade, Strike-slip fault geometry in Turkey and its influence on earthquake activity, Tectonics, 7, 663–684, 1988.

  12. Barka, A. A. and R. Reilinger, Active tectonics of the eastern Mediterranean region deduced from GPS, neotectonic, and seismicity data, Annali Geofisica, 40, 587–610, 1997.

  13. Bariş, Ş., S. B. Üçer, A. Ito, N. Kafadar, H. Alcik, A. Pinar, C. Gürbüz, Y. Honkura, and A. M. Işikara, Local microearthquake network in the western part of the North Anatolian Fault Zone, Japan Earth and Planetary Sciences Meeting, March, 26–29 1996, Osaka, Japan, 1996a.

  14. Bariş, Ş., S. B. Üçer, A. Ito, C. Gürbüz, Y. Honkura, and A. M. Işikara, IZINET: a digital seismic network along the North Anatolian fault in Turkey, Earthquake research in Turkiye State of the Art, Ankara, Turkey, GFZ Publication 63, 1996b.

  15. Bariş, Ş., A. Ito, S. B. Üçer, T. Komut, N. Kafadar, A. Ito, R. Pektaş, Y Honkura, and A. M. Işikara, Microearthquake activity in the western extensions of the North Anatolian Fault Zone in the eastern Marmara region, Turkey (1993–1998), Bull. Seism. Soc. Am., 92, 394–405, 2002.

  16. Bouchon, M., N. Toksöz, H. Karabulut, M. Bouin, M. Dietrich, M. Aktar, and M. Edie, Seismic imaging of the 1999 Izmit (Turkey) rupture inferred from the near-field recordings, Geophys. Res. Lett., 27, 3013–3016, 2000.

  17. Canitez, N. and S. B. Üçer, Computer determinations for the fault plane solutions in and near Anatolia, Tectonophysics, 4, 235–244, 1967.

  18. Christensen, N. I., Poissons’s ratio and crustal seismology, J. Geophys. Res., 101, 3139–3156, 1996.

  19. Delouis, B., D. Giardini, P. Lundgren, and J. Salichon, Joint inversion of InSAR, GPS, teleseismic, and strong-motion data for the spatial and temporal distribution of earthquake slip: application to the 1999 Izmit mainshock, Bull. Seism. Soc. Am., 92, 278–299, 2002.

  20. Demirbağ, E., C. Rangin, X. Le Pichon, and A. M. C. Şengör, Investigation of the tectonics of the Main Marmara Fault by means of deep-towed seismic data, Tectonophysics, 361, 1–19, 2003.

  21. Dewey, J. H. and A. M. C. Şengor, Aegean and surrounding regions: complex multiplate and continuum tectonics in a convergent zone, Geol. Soc. Am. Bull., Part I, 90, 84–92, 1979.

  22. Eberhart-Phillips, D., Three-dimensional velocity structure in northern California Coast Ranges from inversion of local earthquake arrival times, Bull. Seismol. Soc. Am., 76, 1025–1052, 1986.

  23. Eberhart-Phillips, D., Active faulting and deformation of the Coalinga anticline as interpreted from three-dimensional velocity structure and seismicity, J. Geophys. Res., 94, 15565–15586, 1989.

  24. Eberhart-Phillips, D., Three-dimensional P and S velocity structure in the Coalinga region, California, J. Geophys. Res., 95(B10), 15343–15363, 1990.

  25. Eberhart-Phillips, D. and A. J. Michael, Three-dimensional velocity structure, seismicity, and fault structure in the Parkfield region, Central California, J. Geophys. Res., 98, 15767–15758, 1993.

  26. Ergin, M., M. Aktar, F. Bicmen, A. Yoruk, N. Yalcin, and S. Kuleli, Microearthquake study of Izmit Bay, presented at the Active Tectonics Meeting Proc., Vol. 1, Istanbul Technical University, Istanbul, Turkey, 2000.

  27. Eyidoğan, H., A. Çisternaş, C. Gürbüz, M. Aktar, H. Haesler, N. Turkelli, F. Bicmen, S. B. Üçer, S. Kuleli, A. Barka, A. M. Işikara, O. Polat, B. Kaypak, M. Ergin, E. Arpat, A. Yoruk, Ş. Bariş, D. Kalafat, H. Alcik, A. Güngör, S. Ince, E. Zor, T. Bekler, R. Gok, G. Gorgulu, and M. Kara, Marmara Denizi ve Cevresindeki Mikro-Deprem Arastirmasinin Sonuclari, IU DBE Vefa Toplantisi, Istanbul, 1998 (in Turkish).

  28. Finkel, C. F, Earthquakes of the Marmara Sea basin: reflections on the need for co-operation between historian and scientist, 101–111, in Integration of Earth Science Research on the Turkish and Greek 1999 earthquakes, edited by N. Gorur, G. A. Papadopoulos and N. Okay, Kluwer Academic Pub., 207 pp., NATO Science series IV. Earth and Environmental Sciences Vol. 9, 2002.

  29. Genç, M. and M. Mazak, Istanbul Depremleri, IGDAS Publication, Istanbul, Turkey, 2001.

  30. Gürbüz, C, M. Aktar, H. Eyidoğan, A. Çisternaş, H. Haessler, A. Barka, M. Ergin, N. Turkelli, O. Polat, S. B. Üçer, S. Kuleli, Ş. Bariş, B. Kaypak, T. Bekler, E. Zor, F Bicmen, and A. Yoruk, Seismotectonics of the Marmara region (Turkey): results from a microseismic experiment, Tectonophysics, 316, 1–17, 2000.

  31. Gürbüz, C, H. S. Kuleli, T. Bekler, E. Zor, H. Karabulut, and M. Zobu, Crustal structure studies in western Turkey based on earthquake and explosion seismic data, XXVI. General Assembly of The European Seis-mological Commission (ESC), International Association of Seismology and Physics of The Earth’s Interior (IASPEI), International Union of Geodesy and Geophysics (IUGG), 1998.

  32. Gürer, A., Deep conductivity structure of the North Anatolian Fault Zone and the Istanbul and Sakarya Zone along the Geyve-Akcakoca profile, northwest Anatolia, Int. Geology Rev., 38, 727–736, 1996.

  33. Hauksson, E. and J. S. Hasse, Three-dimensional Vp and Vp/Vs velocity models of the Los Angeles basin and central Transverse Ranges, California, J. Geophys. Res., 102, 5423–5453, 1997.

  34. Honkura, Y and A. M. Işikara, Multidisciplinary research on fault activity in the western part of the North Anatolian Fault Zone, Tectonophysics, 193, 347–357, 1991.

  35. Honkura, Y, A. M. Işikara, D. Kolçak, N. Orbay, S. Sipahioğlu, 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.

  36. Honkura, Y, A. M. Işikara, N. Oshiman, A. Ito, B. Üçer, Ş. Bariş, M. K. Tunçer, M. Matsushima, R. Pektaş, C. Celik, S. B. Tank, F Takahashi, R. Yoshimura, Y Ikeda, and T. Komut, Preliminary results of multi-disciplinary 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.

  37. Horasan, G., L. Gülen, A. Pinar, D. Kalafat, N. Özel, H. S. Kuleli, and A. M. Işikara, Lithosperic structure of the Marmara and Aegean regions, western Turkey, Bull. Seism. Soc. Am., 92, 322–329, 2002.

  38. Humphreys, E. and R. W. Clayton, Adaptation of back projection tomography to seismic travel time problems, J. Geophys. Res., 93, 1073–1085, 1988.

  39. Iio, Y, S. Horiuchi, Ş. Bariş, C. Çelik, J. Kyomen, B. Üçer, Y Honkura, and A. M. Işikara, Aftershock distribution in the eastern part of the aftershock region of the 1999 Izmit, Turkey, earthquake, Bull. Seism. Soc. Am., 92, 418–427, 2002.

  40. Ikeda, Y and T. Komut, Surface ruptures associated with the Kocaeli, northwestern Turkey, earthquake of August 17, 1999 (abstracts), J. Seism. Soc. Jpn., 1999 Fall meeting, A64, 1999 (in Japanese).

  41. Ikeda, Y, Y Suzuki, and E. Herece, Late Holocene activity of the North Anatolian Fault Zone in the Orhangazi Plain, in North Western Turkey, Multidisciplinary Research on Fault Activity in the Western Part of the North Anatolian Fault Zone (2), edited by Y Honkura and A. M. Işikara, pp. 16–30, Tokyo Inst. Tech., 1989.

  42. Inoue, H., Y Fukao, K. Tanabe et al., Whole mantle P-wave travel time tomography, Phys. Earth Planet. Inter, 59, 294–328, 1990.

  43. Ishida, M. and A. K. Hasemi, Three-dimensional fine velocity structure and hypocentral distribution of earthquakes beneath the Kanto-Tokai district, Japan,J. Geophys. Res., 93, 2076–2094, 1998.

  44. Işikara, A. M., Y Honkura, N. Watanabe, N. Orbay, D. Kolçak, N. Ohshiman, O. Gündoğdu, and H. Tanaka, Magnetic anomalies in the western part of the North Anatolian Fault Zone and their implications for active fault structure, J. Geomag. Geoelectr, 37, 541–560, 1985.

  45. Ito, A., C. Gürbüz, S. B. Üçer, Ş. Bariş, H. A. Alçik, Y Honkura, and A. M. Işikara, Seismic observation in the western part of the North Anatolian Fault Zone, in Multidisciplinary Research on Fault Activity in the Western Part of the North Anatolian Fault Zone, edited by Y Honkura and A. M. Işikara, 5, pp. 23–32, Boğaziçi University Publ., 1994.

  46. Ito, A., S. B. Üçer, Ş. Bariş, Y Honkura, A. Nakamura, T. Kono, R. Pektaş, T. Komut, A. Hasegawa, and A. M. Işikara, Preliminary Report on the aftershocks of August 17,1999 Izmit Earthquake, Turkey, revealed from micro-earthquake observations, in The 1999 Izmit and Duzce Earthquakes: Preliminary Results, edited by A. Barka, O. Kozaci, S. Akyuz, and E. Altunel, Istanbul Teknik Univ. Yayini, Istanbul, 2000.

  47. Ito, A., S. B. Üçer, Ş. Bariş, A. Nakamura, Y Honkura, T. Kono, S. Hori, A. Hasegawa, R. Pektaş, T. Komut, and A. M. Işikara, Aftershock activity of 1999 Izmit earthquake, Turkey, revealed from microearthquake observations, Bull. Seism. Soc. Am., 92, 418–427, 2002.

  48. Kissling, E., W. L. Ellsworth, D. Eberhart-Phillips, and U. Kradolfer, Initial reference models in local earthquake tomography, J. Geophys. Res., 99, 19635–19646, 1994.

  49. Kuleli, H. S., C. Gürbüz, and M. N. Toksöz, Seismic velocity distribution in the Aegean region, IESCA-1995 Proceedings, 1995.

  50. Lee, W. H. K. and J. C. Lahr, HYP071 (Revised): a computer program for determining hypocenter, magnitude, and first motion pattern of local earthquakes, U. S. Geological Survey Open File Report 75–311, 113 pp., 1975.

  51. Lee, W. H. K. and C. M. Valdes, HYP071PC: a personal computer version of the HYPO71 earthquake location program, U. S. Geological Survey Open File Report 85-749, 43 pp, 1985.

  52. Lees, J. M., Tomographic P-wave velocity images of the Loma Prieta earthquake asperity, Geophys. Res. Lett., 17, 1433–1436, 1990.

  53. McClusky, S., S. Balassanian, A. Barka, C. Demir, S. Ergintav, I. Georgiev, O. Gürkan, M. Hamburger, K. Hurst, H. Kahle, K. Kastens, G. Kekelidze, R. King, V Kotzev, O. Lenk, S. Mahmoud, A. Mishin, M. Nadariya, A. Ouzounis, D. Paradissis, Y Peter, M. Prilepin, R. Reilinger, I. Sanli, H. Seeger, A. Tealeb, M. N. Toksöz, and G. Veis, Global positioning system constraints on plate kinematics and dynamics in the eastern Mediterranean and Caucasus, J. Geophys. Res., 105, 5695–5719, 2000.

  54. McKenzie, D. P., Active tectonics of Mediterranean region, Geophys. J. R. Ast. Soc, 30, 109–185, 1972.

  55. Meade, B. J., B. H. Hager, S. C. McClusky, R. E. Reilinger, S. Ergintav, O. Lenk, A. Barka, and H. Ozener, Bull. Seism. Soc. Am., 92, 208–215, 2002.

  56. Michael, A. J., Effects of three-dimensional velocity structure on the seismicity of the 1984 Morgan Hill, California, aftershock sequence, Bull. Seismol. Soc. Am., 78, 1199–1221, 1988.

  57. Mitsuhata, Y, Y Ogawa, M. Mishina, T. Kono, Y Yokokura, and T. Ushida, Eectromagnetic heterogeneity of the seismogenic region of 1962 M6.5 Northern Miyagi Earthquake, northeastern Japan, Geophys. Res. Lett., 28, 4371–4374, 2001.

  58. Nakajima, J., T. Matsuzawa, D. Zhao, and A. Hasegawa, Three-dimensional structure of Vp, Vs, and Vp/Vs beneath northeastern Japan: implications for arc magmatism and fluids, J. Geophys. Res., 106, 21843–21857, 2001.

  59. Nakamura, A., A. Hasegawa, A. Ito, S. B. Üçer, Ş. Bariş, Y Honkura, T. Kono, S. Hori, R. Pektaş, T. Komut, C. Çelik, and A. M. Işikara, P-wave velocity structure of the crust and its relationship to the occurrence of the 1999 Izmit, Turkey earthquake and aftershocks, Bull. Seism. Soc. Am., 92, 330–338, 2002.

  60. Nicholson, C. and J. M. Lees, Travel-time tomography in the northern Coachelle Valley using aftershocks of the 1986 ML 5.9 North Palm Springs earthquake, Geophys. Res. Lett., 19, 1–4, 1992.

  61. Ogawa, Y., M. Mishina, T. Goto, H. Satoh, N. Oshiman, T. Kasaya, Y. Takahashi, N. 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.

  62. 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.

  63. Okay, A., E. Demirbag, H. Kurt, N. Okay, and I. Kuscu, An active deep-marine strike-slip basin along the North Anatolian fault in Turkey, Tectonics, 18, 129–147, 1999.

  64. Okay, A. I., A. Kaslilar-Ozcan, C. Imren, A. Boztepe-Güney, E. Demirbağ, and I. Kuscu, Active faults and evolving strike-slip basins in the Marmara Sea, northwest Turkey: a multichannel seismic reflection study, Tectonophysics, 321, 189–218, 2000.

  65. Oral, B., R. Reilinger, M. N. Toksöz, R. W. King, A. Barka, I. Kinik, and O. Lenk, Global positioning system offers evidence of plate motion in Eastern Mediterranean, EOS Trans. AGU, 76(2), 9–11, 1995.

  66. Oshiman, N., Y Honkura, M. Matsushima, Ş. Bariş, C. Celik, M. K. Tuncer, 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. Fujiwara and Y Yoshida, pp. 293–303, Terra Scientific Publishing Company, Tokyo, 2002.

  67. Özer, N., M. Hisarli, D. Kolçak, Z. Duzgit, B. Tok, and M. Tankut, Seis-micity of the Marmara Region and it’s indications concerning the other geophysical and geological findings, EOS Trans. AGU, 82(47), F936, 2001.

  68. Paige, C. C. and M. A. Saunders, LSQR: an algorithm for sparse linear equations and sparse least squares, ACM Trans. Math. Software, 8, 43–71, 1982.

  69. Parson, T, S. Toda, R. S. Stein, A. Barka, and J. H. Dieterich, Heightened odds of large earthquakes near Istanbul: An interaction-based probability calculation, Science, 288, 661–665, 2000.

  70. Pektaş R., Recent earthquake clusterings in the eastern part of Marmara region and related problems, M. Sc. Thesis, Boğaziçi University, 2001.

  71. Reilinger, R. E., S. C. McClusky, M. B. Oral, R. King, M. N. Toksöz, A. Barka, I. Kinik, O. Lenk, and I. Sanli, Global positioning system measurements of present day crustal movements in the Arabia-Africa-Eurasia Plate Collision Zone, J. Geophys. Res., 102(B5), 9983–9999, 1997.

  72. Saroğlu, F., O. Emre, and I. Kuscu, Active fault of Turkey. General Directorate of the Mineral Research and Exploration, Ankara, Turkey, 1:2 000 000 scale, 1992.

  73. Seeber, N., J. Armbruster, N. Ozer, M. Aktar, Ş. Bariş, D. Okaya, and Y. Ben-Zion, The 1999 earthquake sequence along the North Anatolian Transform at the juncture between the two main ruptures, and field, in The 1999 Izmit andDuzce Earthquakes: Preliminary Results, edited by A. Barka, O. Kozaci, S. Akyuz, and E. Altunel, pp. 209–223, Istanbul Teknik Uni. Yayini, Istanbul, 2000.

  74. Sellami, S., N. Pavoni, D. Mayer-Rosa, S. Mueller, H. Eyidoğan, M. Aktar, C. Gürbüz, Ş. Bariş, O. Polat, and N. Yalcin, Seismicity and seismotectonics of the Bursa Region, in Active Tectonics of the Northwestern Anatolia—The MARMARA Poly-Project, edited by C. Schindler and M. Pfister, pp. 449–486, vdf Hochschulverlag AG an der ETH Zurich, 570 pp., 1997.

  75. Şengör, A. M. C, N. Görur, and F. Saroğlu, Strike slip faulting and related basin formation in zones of tectonic escape: Turkey as a case study, Soc. Econ. Paleont. Min. Spec. Pub., 37, 227–264, 1985.

  76. Smith, A. D., T. Taymaz, F. Oktay, H. Yuce, B. Alpar, H. Basaran, A. J. Jackson, S. Kara, and U. Simsek, High resolution seismic profiling in the Sea of Marmara (NW Turkey): Late Quaternary sedimentation and sea level changes, GSA Bull., 107/8, 923–936, 1995.

  77. Straub, C. and H. G. Kahle, Global positioning system (GPS) estimates of crustal deformation in the Marmara Sea Region, Northwestern Anatolia, Earth Planet. Sci. Lett., 121, 495–502, 1994.

  78. Straub, C. and H. G. Kahle, Recent crustal deformation and strain accumulation in the Marmara Sea Region, NW Anatolia, inferred from repeated GPS measurements, in Active Tectonics of Northwestern Anatolia, The Marmara Poly Project, edited by C. Schindler, M. Pfister, pp. 417–447, vdf Hochschulverlag AG an der ETH Zurich, 570 pp., 1997.

  79. Tank, S. B., Y Honkura, Y Ogawa, N. Oshiman, M. K. Tuncer, M. Matsushima, C. Çelik, E. Tolak, and A. M. Işikara, Resistivity structure in the western part of the fault rupture zone associated with the 1999 Izmit earthquake and its seismogenic implication, Earth Planets Space, 55, 437–442, 2003.

  80. Taymaz, T., J. Jackson, and D. McKenzi, Active tectonics of the north and central Aegean Sea, Geophys. J. Int., 106, 433–490, 1991.

  81. Thurber, C. H., Local earthquake tomography: velocities and Vp/Vs—theory, in Seismic Tomography: Theory and Practice, edited by H. M. Iyer and K. Hirahara, pp. 563–583, Chapman & Hall, London, 1993.

  82. Toksöz, M. N., A. 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.

  83. Tüncer, M. K., N. Oshiman, Ş. Bariş, Z. Kamaci, M. A. Kaya, A. M. Işikara, and Y Honkura, Further evidence for anomalous magnetic structure along the active fault in western Turkey, J. Geomagn. Geoelectr., 43, 937–950, 1991.

  84. Tüncer, 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.

  85. Üçer, S. B., S. Crampin, R. Evans, A. Miller, and N. Kafadar, The MAR-NET radio-linked seismometer network spanning the Marmara Sea and the Seismicity of Western Turkey, Geophys. J. R. Ast. Soc, 83, 17–30, 1985.

  86. Üçer, S. B., H. Eyidoğan, C. Gürbüz, A. Barka, and S. Bariş, Seismic investigation of the Marmara region, in Active Tectonics of Northwestern Anatolia—The MARMARA Poly-Project, edited by C. Schindler and M. Pfister, pp. 89–100, Hochschulverlag AG an der ETH, Zurich, 500 pp., 1997.

  87. Um, J. and C. Thurber, A fast algorithm for two-point seismic ray tracing, Bull. Seism. Soc. Am., 77, 972–986, 1987.

  88. Unsworth, M. J., P. A. Bedrosian, M. Esiel, G. D. Egbert, and W Siripun-varaporn, Along strike variations in the lectrical structure of the San Andreas Fault at Parkfiled, California, Geophys. Res. Lett., 27, 3021–3024, 2000.

  89. Woith, H., READINESS Project web page, GFZ, Potsdam, Germany, 2003.

  90. Walck, M. C, Three-dimensional Vp/Vs variations for the Coso region, California, J. Geophy. Res., 93(B3), 2047–2052, 1988.

  91. 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.

  92. Yaltirak, C, Tectonic evolution of the Marmara Sea and its surroundings, Mar. Geol., 190, 493–529, 2002.

  93. Yaltirak, C, B. Alpar, M. Sakinc, and H. Yuce, Origin of the Strait of Canakkale (Dardanelles): regional tectonics and the Mediterrenean—Marmara incursion, Mar. Geol., 164, 139–156, with erratum 167, 189–190, 2000.

  94. Yilmaz, Y, S. C. Genç, E. Yigitbas, M. Bozcu, and K. Yilmaz, Geological evolution of the late Mesozoic continental margin of Northwestern Anatolia, Tectonophysics, 243, 155–171, 1995.

  95. Young, R. P. and S. C. Maxwell, Seismic characterization of a highly stressed rock mass using tomographic imaging and induced seismicity, J. Geophys. Res., 97, 12361–12373, 1992.

  96. Zhao, D., A tomographic study of seismic velocity structure in the Japan islans, Ph.D. Thesis, Tohoku Univ., Sendai, Japan, 301 pp., 1991.

  97. Zhao, D. and H. Kanamori, The 1992 Landers earthquake sequence: earthquake occurrence and structural heterogeneities, Geophys. Res. Let., 20, 1083–1086, 1993.

  98. 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.

  99. Zhao, D., A. Hasegawa, and S. Horiuchi, Tomographic imaging of P and S wave velocity structure beneath northeastern Japan, J. Geophys. Res., 97, 19909–19928, 1992.

  100. Zhao, D., A. Hasegawa, A. Yamamoto, and F Ochi, Evidence for the location and cause of large crustal earthquakes in Japan, J. Geophys. Res., 105(B6), 13579–13594, 2000.

  101. Zhao, D., O. P. Mishra, R. Sanda, K. Obara, N. Umino, and A. Hasegawa, Seismological evidence for the influence of fluids and magma on earthquakes, Bull. Earthq. Res. Inst. Univ. Tokyo, 76, 271–289, 2001.

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Correspondence to Yoshimori Honkura.

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Bariş, Ş., Nakajima, J., Hasegawa, A. et al. Three-dimensional structure of Vp, Vs and Vp/Vs in the upper crust of the Marmara region, NW Turkey. Earth Planet Sp 57, 1019–1038 (2005).

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Key words

  • Marmara Sea
  • North Anatolian Fault Zone
  • seismic tomography
  • seismic velocity structure
  • seismicity