عنوان مقاله [English]
Crustal velocity structure and Moho discontinuity depth have investigated beneath 7 the broadband seismic stations, AFRZ, TKDS, TPRV, TNSJ, ANAR, KRSH of the Iranian Seismological Center (ISC) and YZKH of Iranian National Seismic Network (INSN) located in the center of Iran by joint inversion of receiver functions and Rayleigh waves group velocity dispersion. Three years (2012 to 2014) teleseismic waveforms (with epicentral distance 25o-90o) for computation receiver functions by iterative approach in time domain have been processed. The Rayleigh waves group velocity dispersion curves were incorporated into our joint inversion scheme from an independent surface wave tomography study. Receiver function is response of local structure of ground (located beneath the three–component broadband seismic station) to teleseismic P-wave, that is sensitive to seismic discontinuities. Since there is very little absolute-velocity information contained in the receiver function, its inversion for shear-wave velocity structure is non-unique (velocity-depth trade-off). On the other hand, dispersion curves are sensitive to the average velocity structure of the upper layers rather than to seismic discontinuities. So the non-uniqueness problem can be solved by combining receiver function inversion with surface-wave dispersion.
Results from joint inversion in center of Iran indicates that Moho discontinuity depth depth beneath AFRZ, TKDS and TPRV stations is 40 Km, beneath TKDS 42 Km, beneath ANAR is 38 Km and beneath KRSH and YZKH stations are 44 Km. It was shown that the joint inversion method can cause ±2 kilometers of error. The average Moho depth is about 42±2 kilometers beneath center of Iran.
تقیزاده فرهمند، ف. و افسری، ن.، 1394- تعیین ضخامت پوسته در زیر ایستگاههای باند پهن در فلات ایران با استفاده از مدلسازی تابع گیرنده P، نشریه پژوهشهای نوین در زمینلرزه، صص. 65 تا 76.
Alavi, M., 1994- Tectonics of the Zagros orogenic belt of Iran: new data and interpretations. Tectonophysics, 229, 211- 238.
Ammon, C. J., 1991- The isolation of receiver effects from teleseismic P waveforms. Bulletin of the Seismological Society of America, 81, 2504- 2510.
Ammon, C. J., Randall, G. E. and Zandt, G., 1990- On the nonuniqueness of receive function inversions, Journal of Geophysical Research, 95, 15303- 15318.
Berberian, M. and King, G. C. P., 1981- Towards a palaeogeography and tectonic evolution of Iran. Canadian Journal of Erth Sciences, 18, 210- 265.
Berberian, M. and Yeats, R. D., 1999- Patterns of historical earthquake rupture in the Iranian plateau, Bulletin of the Seismological Society of America, 89, 120- 139.
Ghasemi, A. and Talbot, C. J., 2006- A new tectonic scenario for the Sanandaj-Sirjan Zone (Iran). Journal of Asian Earth Sciences, 26, 683- 693.
Hatzfeld, D., Tatar, M., Priestley, K. and Ghafory-Ashtiany, M., 2003- Seismological constraints on the crustal structure beneath the Zagros Mountain belt (Iran), Geophysical. Journal International, 155, 403- 410.
Herrmann, R. B. and Ammon, C. J., 2003- Computer programs in seismology, Version 3.20, Surface waves, Receiver functions and Crustal structure, Saint Louis University, Penn State Univercity.
Jackson, J. and Mckenzie, D. P., 1984- Active tectonics of the Alpine-Himalayan belt between Turkey and Pakistan. Geophysical Journal of the Royal Astronomical Society, 77, 185- 264
Larson, A. M., Snoke, J.A. and James, D. E., 2006- S-wave velocity structure, mantle xenoliths and the upper mantle beneath the Kaapvaal craton. Geophysical Journal International., 167, 171- 186
Lay, T. and Wallace, T.C., 1995- Modern global seismology, Academic Press, San Diego, USA, p. 521.
Ligorrı´a, J. P. and Ammon, C. J., 1999- Iterative deconvolution and receiver function estimation. Bulletin of the Seismological Society of America, 89, 1395- 1400.
Motaghi, M., Tatar, M. and Priestley, K., 2012- Crustal thickness variation across the northeast Iran continental collision zone from teleseismic converted waves, Journal of Seismology 16, 253- 260.
Paul, A., Kaviani, A., Hatzfeld, D., Vergne, J. and Mokhtari, M., 2006- Seismological evidence for crustal-scale thrusting in the Zagros mountain belt (Iran), Geophysical Journal International, 166, 127- 237.
Rahimi, H., Hamzehloo, H., Vaccari, F. and Panza, G. F., 2014- Shear-wave velocity tomography of the lithosphere–asthenosphere system beneath the Iranian Plateau. Bulletin of the Seismological Society of America, 104(6), 2782- 2798.
Tatar, M. and Nasrabadi, A., 2013- Crustal thickness variations in the Zagros continental collision zone (Iran) from joint inversion of receiver functions and surface wave dispersion, journal of Seismology, 17, 1321- 1337.
Vernant, P., Nilforoushan, F., Hatzfeld, D., Abbassi, M., Vigny, C., Masson, F., Nankali, H., Martinod, J., Ashtiani, A., Bayer, R., Tavakoli, F. and Ch´ery, J., 2004- Present-day crustal deformation and plate kinematics in the Middle East constrained by GPS easurements in Iran and northern Oman, Geophysical. Journal International, 157, 381- 398.
Walker, R. and Jackson, J., 2004- Active tectonics and late Cenozoic strain distribution in central and eastern Iran, Tectonics, 23 (5), doi:10.1029/2003TC001529.