Evaluation of Earthquake Potential in the Zagros Region (Iran) Using Seismic Strain and Seismicity Parameters

Document Type : Seismology and Engineering Seismology

Authors

1 Ph.D Candidate, International Institute of Earthquake Engineering and Seismology (IIEES), Tehran, Iran.

2 Assistant Professor, International Institute of Earthquake Engineering and Seismology (IIEES), Tehran, Iran.

3 Assistant Professor, Department of physics, Persian Gulf University, Bushehr, Iran.

Abstract

In this paper seismic strain andGutenberg-Richter b-value are used to quantify seismic potential in the Zagros region(Southwest Iran). Seismicity data of the Zagros are extracted from International Seismological Center and Iranian Seismological Center bulletins in timeinterval 1963 to 2015. The b-values are estimated using Kijko-Sellevoll method. The results represent that b-value varies from 0.62 to0.72in the study region.Low b-values (0.62 and 0.72) are accompanied with higher strain rates (1.22×10-8 and 7.46×10-9) in southern parts of the Zagros indicating more frequent large earthquakes. On the other hand, Low b-values (0.64 and 0.72) and lower strain rates (2.39×10-9 and 8.54×10-10) in northern parts of the Zagros indicate less frequent large earthquakes. Recurrence interval of large earthquakes(M>6) is estimated using the b-values and seismic strain rates.Recurrence interval of large earthquakes in southern parts of the Zagros (7 and 8 years) are shorter than northern parts of the Zagros (19 and 45 years).

Keywords


Agard, P., Omrani, J., Jolivet, L., and Mouthereau, F. (2005) Convergence history across Zagros (Iran): constraints from collisional and earlier deformation. Int. J. Earth Sci., 94, 401-419.
Mouthereau, F., Lacombe, O., and Verges, J. (2012) Building the Zagros collisional orogen: timing, strain distribution, and the dynamics of Arabia/Eurasia plate convergence. Tectonophysics, 532-535, 27-60.
Sella, G.F., Dixon, T.H., and Mao, A. (2002) REVEL: a model for recent plate velocities from space geodesy. J. Geophys. Res., 107(B4), 11-30.
Walpersdorf, A., Hatzfeld, D., Nankali, H., Tavakoli, F., Nilforoushan, F., Tatar, M., Vernant, P., Chery, J., and Masson, F. (2006) Difference in the GPS deformation pattern of North and Central Zagros (Iran). Geophys. J. Int., 167, 1077-1088.
Vernant, P., Nilforoushan, F., Hatzfeld, D., Abbassi, M.R., Vigny, C., Masson, F., Nankali, H., Martinod, J., Ashtiani, A., Bayer, R., Tavakoli, F., and Chery, J. (2004) Present-day crustal deformation and plate kinematics in the Middle East constrained by GPS measurements in Iran and northern Oman. Geophys. J. Int., 157, 381-398.
Mostafazadeh, M., Alptekin, O., and Oncel, A.O. (2000) Body waveform modeling of five moderately earthquakes in the Zagros fold thrust belt. Journal of Seismology and Earthquake Engineering, 2(3), 1-10.
Talebian, M. and Jackson, J. (2004) A reappraisal of earthquake focal mechanisms and active shortening in the Zagros mountains of Iran. Geophys. J. Int., 156, 506-526.
Walker, R.T., Andalibi, M.J., Gheitanchi, M.R., Jackson, J.A., Karegar, S., and Priestley, K. (2005)Seismological and field observations from the 1990 November 6 Furg (Hormozgan) earthquake: a rare case of surface rupture in the Zagros Mountains of Iran. Geophys. J. Int., 163, 567-579.
Baker, C., Jackson, J., and Priestley, K. (1993) Earthquakes on the Kazerun line in the Zagros Mountains of Iran: strike-slip faulting within a fold-and-thrust belt. Geophys. J. Int., 115, 41-61.
Berberian, M. (1995) Master blind thrust faults hidden under the Zagros folds: Active basement tectonics and surface morphotectonics. Tectonophysics, 241, 193-224.
McQuarrie, N. (2004) Crustal-scale geometry of the Zagros fold-thrust belt, Iran. J. Struct. Geol., 26, 519-535.
Jackson, J. and McKenzie, D. (1988) The relationship between plate motions and seismic moment tensors and the rates of active deformation in the Mediterranean and Middle East. Geophys. J. Int., 93(1), 45-73.
Ekstrom, G. and England, P. (1989) Seismic strain rates in regions of distributed continental deformation. J. Geophys. Res., 94(B8), 10231-10257.
Jackson, J., Haines, J., and Holt, W. (1995) The accommodation of Arabia-Eurasia plate convergence in Iran. J. Geophys. Res., 100, 15205-15219.
Masson, F., Chery, J., Hatzfeld, D., Martinod, J., Vernant, P., Tavakoli, F., and Ghafory-Ashtiani, M. (2005) Seismic versus aseismic deformation in Iran inferred from earthquakes and geodetic data. Geophys. J. Int., 160, 217-226.
Gutenberg, B. and Richter, C.F. (1954) Seismicity of the Earth and Related Phenomena. Princeton University Press. Princeton.
Wiemer, S., McNutt, S.R., and Wyss, M. (1998) Temporal and three dimensional spatial analysis of the frequency-magnitude distribution near Long Valley caldera, California. Geophys. J. Int., 134, 409-421.
Wyss, M., Sammis, C.G., Nadeau, R.M., and Wiemer, S. (2004) Fractal dimension and b value on creeping and locked patches of the San Andreas Fault near Parkfield, California. Bull. Seism. Soc. Am., 94, 410-421.
Mogi, K. (1962) Magnitude-frequency relation for elastic shocks accompanying fractures of various materials and some related problems in earthquakes. Bull. Ear thquake Res. Inst. Tokyo Univ., 40, 831-853.
Scholz, C.H. (1968) The frequency-magnitude relation of micro fracturing in rock and its relation to earthquakes. Bull. Seism. Soc. Am., 58, 399-415.
Frohlich, C. and Davis, S. (1993) Teleseismic b-values: or, much ado about 1.0. J. Geophys. Res., 98, 631-644.
Gutenberg, B. and Richter, C.F. (1944) Frequency of earthquakes in California. Bull. Seism. Soc. Am., 34, 185-188.
Tsapanos, T.M. (1990) b-values of two tectonic parts in the Circum-Pacific belt. Pure Appl. Geophys., 134, 229-242.
Urbancic, T.I., Trifu, C.I., Long, J.M., and Young, R.P. (1992) Space time correlations of b-values with stress release. Pure Appl. Geophys., 139, 449-462.
Wyss, M. (1973) Towards a physical understanding of the earthquake frequency distribution. Geophys. J. R. Astr. Soc., 31, 341-359.
Schorlemmer, D., Wiemer, S., and Wyss, M. (2005) Variations in earthquake size distribution across different stress regimes. Nature, 437, 539-542.
International Seismological Center [Online]. Available: www.isc.ac.uk [2015, March 19].
Iranian Seismological Center [Online]. Available: http://irsc.ut.ac.ir/bulletin.php/ [2015, March 19].
Heaton, T.H. and Kanamori, H. (1984) Seismic potential associated with subduction in the northwestern United States. Bull. Seism. Soc. Am., 74, 933-941.
Shahvar, M.P., Zare, M., and Castellaro, S. (2013) A unified seismic catalog for the Iranian plateau (1900-2011). Seism. Res. Lett., 84(2), 233-249.
Harvard University Seismology Department [Online]. Available: http://www.Globalcmt. org/CMT search.html [2015, March 19].
Molnar, P. (1983) Average regional strain due to slip on numerous faults of different orientations. J. Geophys. Res., 88, 6430-6432.
Pujol, J. (2003) 'The earthquake source in un bounded media'. In: Elastic Wave Propagation and Generation in Seismology, Cambridge University Press. Cambridge, 316-356.
Kijko, A. and Sellevoll, M.A. (1989) Estimation of earthquake hazard parameters from incomplete data files. Part I. utilization of extreme and complete catalogs with different threshold magnitudes. Bull. Seism. Soc. Am., 79(3), 645-654.
Ward, S. (1994) A multidisciplinary approach to seismic hazard in southern California. Bull. Seism. Soc. Am., 84(5), 1293-1309.
Maggi, A., Jackson, J.A., Priestley, K., and Baker, C. (2000) A re-assessment of focal depth distributions in Southern Iran, the Tien Shan and Northern India: do earthquakes really occur in the continental mantle? Geophys. J. Int., 143, 629-661.
Malekzade, Z., Abbassi, M.R., Bellier, O., and Authemayou, C. (2007) Strain partitioning in west-central Zagros fold and thrust belt: implication for seismic hazard analysis. Journal of Seismology and Earthquake Engineering, 9(3), 85-98.
Reasenberg, P. (1985) Second-order moment of central California seismicity, 1969-1982. J. Geophys. Res., 90(B7), 5479-5495.
Woessner, J. and Wiemer, S. (2005) Assessing the Quality of Earthquake Catalogues: Estimating the Magnitude of Completeness and Its Uncertainty. Bull. Seism. Soc. Am., 95(2), 684-698.
Baker, C. (1993) Active Seismicity and Tectonics of Iran. PhD Thesis, University of Cambridge, Cambridge.
Tatar, M., Hatzfeld, D., and Ghafory-Ashtiani, M. (2004) Tectonics of the Central Zagros (Iran) deduced from microearthquake seismicity. Geophys. J. Int., 156, 255-266.
Yamini-Fard, F., Hatzfeld, D., Tatar, M., and Mokhtari, M. (2006) Microseismicity at the intersection between the Kazerun fault and the Main Recent Fault (Zagros-Iran). Geophys. J. Int., 166, 186-196.
Yamini-Fard, F., Hatzfeld, D., Farahbod, A.M., Paul, A., and Mokhtari, M. (2007) The diffuse transition between the Zagros continental collision and the Makran oceanic subduction (Iran): microearthquake seismicity and crustal structure. Geophy. J. Int., 170, 182-194.
Ashkpour, M.S. and Mostafazadeh, M. (2008) Source parameters of the Mw 5.8 fin (South of Iran) earthquake of March 25, 2006. World Appl. Sci. J., 4(1), 104-115.
Gholamzadeh, A., Yamini-Fard, F., Hessami, K., and Tatar, M. (2009) The February 28, 2006 Tiab earthquake, Mw 6.0: implications for tectonics of the transition between the Zagros continental collision and the Makran subduction zone. Journal of Geodynamics, 47, 280-287.
Yamini-Fard, F., Hassanpour Sedghi, M., Gholamzadeh, A., Tatar, M., and Hessami, K. (2012) Active faulting of the Southeastern-most Zagros (Iran): microearthquake seismicity and crustal structure. Journal of Geodynamics, 55, 56-65.
Sepahvand, M.R., Yamini-Fard, F., Tatar, M., and Abbassi, M.R. (2012) Aftershock study of the 2006 Silakhur earthquake (Zagros, Iran): Seismological evidence for a pull-Apart basin along the main Recent Fault, Doroud segments. Journal of Seismology, 16(2), 233-251.
International Institute of Earthquake Engineering and Seismology [Online]. Available: www.iiees.ac.ir [2015, March 19].
Hanks, T.C. and Kanamori, H. (1979) A moment magnitude scale. J. Geophys. Res., 84, 2348-2350.