Document Type : Original Research Paper

Authors

1 Ph.D., Institue of Geophysics, University of Tehran, Tehran, Iran

2 Associate Professor, Institue of Geophysics, University of Tehran, Tehran, Iran

3 Assistant Professor, Institue of Geophysics, University of Tehran, Tehran, Iran

Abstract

In this study, we have used recorded local earthquakes by 17 permanet seismic stations to separate intrinsic and scattering attenuation in North-West of Iranian pleateau. Intrinsic and scattering attenuation can be applied as useful tools to study the geodynamic and tectonic characteristics of a region. They also represent thermal, compositional and deformational characteristics of the crust and upper mantle. The wave attenuation has strong correlation with seismicity and heterogeneity of medium and is regularly used in the study of tectonically active regions of the world. Single backscattering and coda normalized methods are used to estimate the coda Q (Qc) and Qs respectively, using 14,969 earthquakes which are recorded by the stations. The results show this region is very active region tectonically and seismically. Due to low values of Quality factor and thus high attenuation values of body and shear waves in North West part of Iran, amplitude of the propagated waves are decreased severely in the interested area.The intrinsic attenuation and the Coda wave attenuations curves around the North Tabriz fault are closer in comparison with entire northwestern Iran region and Tabriz city, indicating a strong attenuation of the earthquake waves around this fault system. Similarly, these curves are closer in Tabriz city than those calculated for the northwestern region of Iran which expresses the overriding intrinsic attenuation from the effect of dispersion. The attenuation effect of seismic waves reduces the damages caused by earthquakes at appropriate distances of faults at the time of earthquake occurrence.

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Abubakirov, I. R. and Gusev, A. A., 1990- Estimation of scattering properties of the lithosphere of Kamchatka based on Monte Carlo simulation of record envelope of a near earthquake. Phys. Earth planet. Inter., 64, 52- 67.
Aki, K. and Chouet, B., 1975- Origin of coda waves: source, attenuation, and scattering effects. J. geophys. Res., 80, 3322- 3342.
Aki, K., 1969- Analysis of the seismic coda of local earthquakes as scattered waves. J. geophys. Res., 74, 615- 631.
Aki, K., 1980- Scattering and attenuation of shear waves in the lithosphere. J. Geophys. Res. 85, 6496- 6504.
Ahmadzadeh, M., Sobouti, F. and Rahimi, H., 2015- Lateral and depth variations of coda Q in the Zagros region of Iran. J. Seismol. 19 (3), 1- 15.
Bianco, F., Castellano, M., Del Pezzo, E. and Iba˜nez, J. M., 1999- Attenuation of short-period seismic waves at Mt. Vesuvius, Italy. Geophys. J. Int., 138, 67- 76.
Bianco, F., Del Pezzo, E., Castellano, M., Iba˜nez, J. and Di Luccio, F., 2002- Separation of intrinsic and scattering seismic attenuation in the Southern Apennine zone, Italy. Geophys, J. Int., 150, 10- 22.
Chang, J., Chen, Y. and Shin, T., 2009- Spatial distribution of coda Q estimated from local earthquakes in Taiwan area. Earth Planets Space., 61, 1077- 1088.
Del Pezzo, E. and Scarcella, G., 1986- Three–component coda Q in the Abruzzi-Molise region, Central Apennines, Ann. Geophys., 4, 589- 592.
Del Pezzo, E., Iba˜nez, J., Morales, J., Akinci, A. and Maresca, R., 1995- Measurements of intrinsic and scattering seismic attenuation in the crust. Bull. Seism, Soc. Am., 85, 1373- 1380.
Der, Z., 1998- High frequency P- and S- wave attenuation in the earth: Pure Appl. Geophys, 153, 273- 310.
Dewey, J. F. Hempton M. R. Kidd, W. S. F. Saroglu, F. and Sengor, A. M. C., 1986- Shortening of continental lithosphere: The tectonics of eastern Anatolia - A young collision zone. Geol. Soc. Spec. Publ., 19- 36.
Farrokhi, M., Hamzehloo, H, Rahimi, H. and Allameh Zadeh, M., 2016- Separation of intrinsic and scattering attenuation in the crust of central and eastern Alborz region, Iran. Phys Earth Planet Inter 253:88- 96.
Gholamzadeh, A., Rahimi, H. and Yaminifard, F., 2014- Spatial and temporal variation of codawaveattenuation in the Faryab Region, Southeast of the Sanandaj–Sirjan Zone, using aftershocks of the Tiab earthquake of 28 February 2006. Bull. Seismol. Soc. Am. 104. http://dx.doi.org/10.1785/0120130072 No. 1 dio.
Hassani, B., Zafarani, H., Farjoodi, J. and Ansari, A., 2011- Estimation of site amplification, attenuation and source spectra of S-waves in the East-Central Iran. Soil Dynamics and Earthquake Engineering, Vol. 85, pp. 17- 30.
Hatzidimitriou, P. M., 1995- S-wave attenuation in the crust in northern Greece. Bull. seism. Soc. Am., 85, 1381- 1387.
Hoshiba, M., 1993- Separation of scattering attenuation and intrinsic absorption in Japan using the Multiple Lapse Time-Window Analysis of full seismogram envelope. J. geophys. Res., 98, 15809- 15824
Kamalian, N., Hamzeloo, H. and Ghasemi, H., 2007- S-wave attenuation and spectral decay parameter for the Avaj region, Iran. Iranian Journal of Science and Technology, Vol. 31, pp. 63- 71,
Karato, S., 1998- A dislocation model of seismic wave attenuation and micro-creep in the earth: Harold Jeffreys and the rheology of the solid earth. Pure Appl. Geophys, 153, 239- 256.
Lay, T. and Wallace. T. C., 1995- Modern Global Seismology, Academic Press, San Diego.
Ma’hood, M. and Hamzehloo, H., 2009- Estimation of coda wave attenuation in East Central Iran. J. Seismol., 13, 125- 139, doi:10.1007/s10950-008- 9130-2.
Minster, J., 1980- Anelasticity and attenuation, in Dziewonski. physics of the earth’s interior, North-Holland, Amsterdam, 152- 212.
Mitchell, B. J., 1995- Anelastic structure and evolution of the continental crust and upper mantle from seismic surface wave attenuation. Rev Geophys, 33, 441- 462.
Mitchell, B. J., Pan, Y., Xie, J. and Cong, L., 1997- Lg coda Q variation across Eurasia and its relation to crustal evolution. J. Geophys. Res. 102, 22,767- 22,779.
Moradi, A. S., Hatzfeld, D. and Tatar, M., 2011- Microseismicity and seismotectonics of the North Tabriz fault (Iran). Tectonophysics, 506, 22- 30.
Mousavi, M., Zafarani, H., Noorzad, A., Ansari, A. and Bargi, K., 2007- Analysis of Iranian strong motion data using the specific barrier model. Journal Geophysics and Engineering, Vol. 4, pp.1- 14.
Rahimi, H. and Hamzehloo, H., 2008- Lapse time and frequency-dependentattenuation of coda waves in the Zagros continental collision zone inSouthwestern Iran.J. geophys. Eng.5,173- 185
Rahimi, H., Hamzehloo, H. and Kamalian, N., 2010a- Estimation of Coda and shear wave Attenuation in the Volcanic area in SE Sabalan Mountain, NW Iran. Acta Geophys., 58, 244- 268.
Rahimi, H., Motaghi, K., Mukhopadhyay, S. and Hamzehloo, H., 2010b- Variation of coda wave attenuation in the Alborz region and central Iran, Geophys. J. Int., 181, 1643- 1654.
Rizza, M., Vernant, P., Ritz, J. F., Peyret, M., Nankali, H., Nazari, H., Djamour, Y., Salamati, R., Tavakoli, F., Chery, J., Mahan, S. A. and Masson, F., 2013- Morphotectonic and geodetic evidence for a constant slip-rate over the last 45 kyr along the Tabriz fault (Iran), Geophys. J. Int., 193, 1083- 1094, doi: 10.1093/gji/ggt041.
Romanowicz, B. and Durek, J., 2000- Seismological constrains on attenuation in the earth: a review: Earth’s deep interior: mineral physics and tomography from atomic to the global scale. Geophysical Monograph 117, American Geophysical Union, 161- 179.
Safarshahi, M., Hamzeloo, H., Rezapour, M., Sinaeian, F., Farzanegan, E. and Mirzaei, H., 2011- Estimation of QS in southern Iran, using strong motion data of Rigan earthquakes (2010 & 2011). 1st International Conference of Urban Construction in the Vicinity of Active Faults, Tabriz, Iran.
Samaei, M., Miyajima, M., Tsurugi, M. and Fallahi, A., 2013- Source and path parameters for recorded earthquakes in Tehran Province, Iran, Journal of Japan Society of Civil Engineers, Ser. A1 (Structural Engineering & Earthquake Engineering (SE/EE)), 69 (4), I_980-I_988.
Sato, H., 1977- Energy propagation including scattering effects: single isotropic approximation. J.Phys. Earth., 25, 27- 41.
Şengör, A. M. C. and Kidd, W. S. F., 1979- The post-collisional tectonics of the Turkish-Iranian Plateauand a comparison with Tibet. Tectonophysics, 55, 361- 376.
Stein, S. and Wysession, M., 2003- An Introduction to seismology, earthquake and earth structure. Blackwell Pub.
Wennerberg, L., 1993- Multiple–scattering Interpretation of coda-Q Measurements. Bull. Seismol. Soc Am., 83, 279- 290.
Wu, R.S., 1985- Multiple Scattering and Energy Transfer of Seismic Waves, Separation of Scattering Effect from Intrinsic Attenuation, I. Theoretical Modeling. Geophys, J. R. Astron. Soc., 82, 57- 80.
Yoshimoto, K., Sato, H. and Ohtake, M., 1993- Frequency-dependent attenuation of P and S waves in Kanto area Japan based on the coda-normalization method. Geophys. J. Int., 114, 165- 174.
Zafarani, H., Mousavi, M., Noorzad, A. and Ansari, A., 2008- Calibration of the specific barrier model to Iranian plateau earthquakes and development of physically based attenuation relationships for Iran. Soil Dynamics and Earthquake Engineering, Vol.28 pp. 550- 576.
Zeng, Y., 1991- Compact Solutions for Multiple Scattered Wave Energy in Time Domain. Bull. Seismol. Soc. Am., 81, 1022- 1029.