Document Type : Original Research Paper
Authors
1 National Cartographic Center of Iran, Geodesy and Geodynamics Department Tehran, Iran
2 Khajeh Nasridin Toosi, University of Technology, Faculty of Geodesy and Geomatics Engineering, Tehran, Iran
3 Institute for Advanced Studies in Basic Sciences, Department of physics, Zanjan, Iran
4 International Institute of earthquake of Engineering and Seismology, Tehran, Iran
5 Research Institute for Earth Science, Geological Survey of Iran, Tehran, Iran
Abstract
A three-dimensional lithosphere model with horizontal dimensions of 1500 km×600 km and a depth extent of 70 km for the Zagros is constructed from available geophysical data to find out strength of the outermost layers in this area. The structural boundaries of the model are based on the results from the deep seismic sounding profiles. First the finite element model for the temperature is solved in order to obtain initial temperature and the geotherm, after that structural viscoelastic problem is solved using the same mesh as in the thermal initial condition. Preliminary results for wet and dry rheology indicate that the depth of the BDT is about 8 km and 11 km for hot geotherm and 10.5 km to14 km for cold geotherm. The results are in good agreement with focal depth in the Zagros that most earthquakes occur in 8 to 15 km depth (Tatar et al., 2004 and Jackson et al., 2008), that the long-term strength of the continental lithosphere resided only in its upper part, which was contained wholly within the crust.
Keywords
References
Alavi, M., 1994- Tectonics of the Zagros orogenic belt of Iran: new data and interpretations, Tectonophysics, 229, 211–238.
Alavi, M., 2004- Regional stratigraphy of the Zagros fold-thrust belt of Iran and its proforeland evolution, Am. J. Sci., 304, 1–20.
Artemieva, I. M., and Mooney D. W., 2001- Thermal thickness and evolution of Precambrian lithosphere A global tudy, JGR, VOl106, No.B8,16387-16414
Authemayou, C., Bellier, O., Chardon, D., Malekzade, Z. & Abassi, M., 2005- Role of the Kazerun fault system in active deformation of the Zagros fold-and-thrust belt (Iran), Comptes Rendus Geoscience, 337(5), 475–547.
Authemayou, C., Chardon, D., Bellier, O., Malekzade, Z., Shabanian, I. & Abbassi, M., 2006- Late Cenozoic Partitioning of oblique plate convergence in the Zagros fault-and-thrust belt (Iran), Tectonics, 25, TC3002, doi:10.1029/2005TC001860, 2006.
Baker, C., Jackson, J. & Priestley, K., 1993- Earthquakes on the Kazerun Line in the Zagros mountains of Iran: strike-slip faulting within a foldand- thrust belt, Geophys. J. Int., 115, 41–61.
Berberian, M., 1981- Active faulting and tectonics of Iran, in Zagros-Hindu- Kush-Himalaya Geodynamic evolution,Vol. 3, pp. 33–69, eds Gupta, H.K. & Delany, F.M., Am. Geophys. Union, Geodyn. Ser.
Berberian, M., 1995- Master blind thrust faults hidden under the Zagros folds: active basement tectonics and surface morphotectonics, Tectonophysics,241, 193–224.
Berberian, M. & King, G. C. P., 1981- Towards a paleogeography and tectonic evolution of Iran, Can. J. Earth Sci., 18, 210–265.
Bird, P., Toks¨oz, M.N.&Sleep, N.H., 1975- Thermal and mechanical models of continent-continent convergence zones, J. geophys. Res., 32, 4405–4416.
Bird, P., 1978- Finite element modeling of lithosphere deformation: the Zagros collision orogeny, Tectonophysics, 50, 307–336.
Bird, P., Kong, X., 1994- Computer simulations of California tectonics confirm very low strength of major faults, Geol. Soc. Amer. Bull. 106 (2).159–174.
Bird, P., 1998- Testing hypotheses on plate-driving mechanisms with global lithosphere models including topography, thermal structure, and faults, J., Geophys. Res. 103 (B5) 10115–10130.
Bird, P., J.,1984- Baumgardner, Fault friction, regional stress, and crust–mantle coupling in southern California from finite element methods, J. Geophys. Res. 89.1932–1944.
Brace, W. F. & Kohlstedt, D. L., 1980- Limits on lithospheric stress imposed by laboratory experiments. J. Geophys. Res., 85, 6248–6252.
Burov, E. B, Watts, A. B., 2006- The Long term strength of Continental Lithosphere Jelly sandwich or crème brulee,GSA Today,VOL16,NO1
Byerlee, J. D., 1967- Frictional characteristics of granite under high confining pressure. J. Geophys. Res., 72, 3639–3648.
Byerlee, J. D., 1978- Friction of rocks. Pure and applied Geophysics, 116,615–626.
Carter, N. L, Tsenn, M. C., 1987- Flow properties of continental lithosphere, Tectonophysics 136 27–63.
Chery, J., Vilotte, J. P. & Daignieres, M., 1991- Thermomechanical model of a thinned continental lithosphere under compression: implications for the Pyrenees. J. Geophys. Res. 96, 4385–4412.
Ch´ery, J., Zoback, M. D. & Hassani, R., 2001- An integrated mechanical model of the San Andreas Fault in central and northern California. Journal of Geophysical Research, 106(B10): 22 051–22 066.
Chery. J, Zoback, M. D., Hickman.S, 2004- A mechanical model of the San Andreas fault and SAFOD Pilot Hole stress easurements ,GRL,VOL31 ., 31, L15S13, doi:10.1029/2004GL019521.
Chopra, PN, Paterson, MS., 1981- The experimental deformation of dunite. Tectonophysics 78 : 453–473
Christensen, N. I., 1996- Poissons’s ratio and crustal seismology, J. geophys.Res., 101, 3139–3156.
Christensen, N. I. & Mooney, W. D., 1995- Seismic velocity structure and composition of the continental crust: A global view, J. geophys. Res.,100, 9761–9788.
Caristan, Y., 1982- The transition from high temperature creep to fracture in Maryland diabase, J. Geophys. Res., 87, 6781–6790.
Carter, N. L. and M. C., 1987- Tsenn, Flow properties of the lithoshpere, Tectonophysics, 136, 27–63.
Christensen, N. I., 1996- Poisson’s ration and crustal seismology, J. Geophys. Res., 101, 3139–3156.
Christensen, N. I. and Mooney, W. D., 1995- Seismic velocity structure and composition of the continental crust: A global view, J. Geophys. Res.,100, 3047–3054,.
Engdahl,, E. R., James, A., Jackson, Stephen, C. Myers, Eric A., Bergman and K., Priestley., 2006- Relocation and assessment of seismicity in the Iran region Geophys. J. Int. (2006) 167, 761–778
Fernandez, M., Ranalli,G.,1997- The role of rheology in extensional basin formation modeling, Tectonophysics 282 (1997) 129-145
Gerbault, M., Henrys.S. and Davey, F., 2003- Numerical models of lithospheric deformation forming the Southern Alps of New Zealand JGR,VOL108,NO.0
Gerbault, M., Henrys, S., and Davey, F., 2002- Three-dimensional lateral crustal thickening in continental oblique collision: an example from the Southern Alps, New Zealand.
Hansen, F. D. and N. L., Carter, 1983- Semibrittle creep of dry and wet Westerly granite at 1000 MPa, Proc. U.S. Symp. Rock Mech., 24th, 429– 447.
Hatzfeld, D., Tatar, M., Priestley, K. & Ghafory-Ashtyany, M., 2003- Seismological constraints on the crustal structure beneath the Zagros mountain belt (Iran), Geophys. J. Int., 155, 403–410.
Hessami, K., Koyi, H., Talbot, C. J., Tabasi, H. & Shabanian, E., 2001- Progressive unconformities within and evolving foreland fold-thrust belt, Zagros Mountains, J. geol. Soc. Lond., 158, 969–981.
Jackson, J. & McKenzie, D., 1984- Active tectonics of the Alpine-Himalayan belt between Turkey and Pakistan. Geophysical Journal of the Royal Astronomical Society, 77, 185–264.
Jackson, J., 1980- Errors in focal depth determination and the depth of seismicity in Iran and Turkey, Geophys. J. R. astr. Soc., 61, 285–301.
Jackson, J. & Fitch, T., 1981- Basement faulting and the focal depths of the larger earthquakes in the Zagros mountains (Iran), Geophys. J. R. astr. Soc., 64, 561–86.
Jackson, J. & Mc.kenzie, 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. R. astr. Soc. Lond., 83, 45–73.
Jackson, J., Haines, J. & Holt, W.,1995- The accommodation of Arabia-Eurasia plate convergence in Iran, J. geophys. Res., 100, 15 205–15 219.
Jackson, J., 2002- Strenght of continental lithosphere,GSA TODAY,September,2002.
Jackson, J., Makenzie, D., Priestly K., Emmerson, B., 2008- New views on the structure and rheology of the lithosphere, Journal of the Geological Society, London, Vol. 165 pp. 453–465. Printed in Great Britain.453
Kaviani, A., 2007- A strong seismic velocity contrast in the shallow mantle across the Zagros collision zone (Iran), Geophys. J. Int. (2007) doi: 10.1111/j.1365-246X.2007.03535.x
Kirby, S., 1983- Rheology of the lithosphere. Reviews of Geophysics and Space Physics, 21, 1458–1487.
Kohlstedt, D. L., 1995- Strength of the lithosphere: constraints imposed by laboratory experiments. Journal of Geophysical Research, 100, 17587–17 602.
Liu, Z. & Bird, P., 2007- Kinematic modelling of neotectonics in the Persia–Tibet–Burma orogen , Geophys. J. Int. (2007) doi: 10.1111/j.1365-246X.2007.03640.x
Maggi, A., Jackson, J. A., Priestley, K. & 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.
Maggi, A. & Priestley, K., 2005- Surface waveform tomography of the Turkish-Iranian plateau, Geophys. J. Int., 160, 1068–1080.
Masson, F., Ch´ery, J., Hatzfeld, D., Martinod, J., Vernant, P., Tavakoli, F. & Ghafory-Ashtiani, M., 2005- Seismic versus aseismic deformation inIran inferred from earthquakes and geodetic data, Geophys. J. Int., 160, 217–226.
Masson, F., Anvari M., Djamour, Y., Walpersdorf, A., Tavakoli, F., Daignières, M., Nankali, H. and Gorp S.V., 2005- Large-scale velocity field and strain tensor in Iran inferred from GPS measurements: new insight for the Present-day deformation pattern withinNE Iran, Geophys. J. Int.
Meissner, R. & Strehlau, J., 1982- Limits of stresses in continental crusts and their relation to the depth-frequency distribution of shallow earthquakes. Tectonics, 1, 73–89.
Morgan, P., Sass, J. A., 1984- Thermal regime of the continental lithosphere, J. Geodyn. 1 (1984) 143–166.
Moisio, K, Kaikkonen, P., 2006- Three-dimensional numerical thermal and rheological modeling in the central Fennoscandian Shield, GEOD-754; No. of Pages 20 Journal of Geodynamics xxx (2006) xxx–xxx
Ni, J. & Barazangi, M., 1986- Seismotectonics of the Zagros continental collision and comparison with the Himalayas. J. geophys. Res., 91, 8205–8218.
Parsons, T., 2002- Post-1906 stress recovery of the San Andreas fault system calculated from three-dimensional finite element analysis, Journal of Geophysical Research, vol. 107, no. B8, 10.1029/2001JB001051, 2002
Parsons, T., 2006- Tectonic stressing in California modeled from GPS observations J. Geophys. Res., 111, B03407,doi:10.1029/2005JB003946.
Parsons, T., Bruns, T. R. and Sliter, R., 2005- Structure and mechanics of the San Andreas–San Gregorio fault junction, San Francisco, California, Geochem. Geophys. Geosyst., 6, Q01009, doi:10.1029/2004GC000838
Paul, A., Kaviani, A, Hatzfeld, D., Vergne, J., Mokhtari, M., 2006- Seismological evidence for crustal-scale thrusting in the Zagros mountain belt (Iran), Geophys. J. Int. (2006) doi: 10.1111/j.1365-246X.2006.02920.x
Pinet, C., Jaupart, C., 1987- The vertical distribution of radiogenic heat production in the Precambrian crust of Norway and Sweden: geothermal implications, Geophys. Res. Lett. 14 (1987) 260–263.
Pinet, C. et al., 1991- Heat flow and structure of the lithosphere in the EasternCanadian shield, J. Geophys. Res. 96 (1991) 19941–19963.
Pinet, C., Jaupart, C., Marschol, J. C., Gariepy, G., Bienfait, G. & Lapointe, R., 1991- Heat flow and structure of the lithosphere in the eastern Canadian shield. J. geophys. Res., 96, 19 941–19 963.
Ranalli, G., 1995- Rheology of the Earth, 2nd edn. Allen and Unwin, London
Rice, J. R., 1992- Fault stress states, pore pressure distributions, and the weakness of the San Andreas fault. Fault Mechanics and Transport Properties of Rock. B.E. a. T.-F. Wong. San Diego, Calif., Academic: 475–503.
Scholz, C. H., 1990- The Mechanics of Earthquakes and Faulting. CambridgeUniversity Press, Cambridge.
Sibson, R. H., 1982- Fault zone model, heat flow, and the depth distribution of earthquakes in the continental crust of the united states. Bull. Seism. Soc. Am., 72, 151–163.
Shelton, G., Tullis J., 1981- Experimental flow laws for crustal rocks, EOS 62 : 396
Stocklin, J., 1974- Possible ancient continental margin in Iran, in Geology of Continental Margins, pp. 873–877, eds Burke, C. & Drake, C., Springer-Verlag, NewYork.
Stoneley, R., 1981- The geology of the Kuh-e-Dalneshin area of southern Iran, and its bearings on the evolution of southern Thetys, J. geol. Soc.Lond., 138, 509–526.
Snyder, D. B. & Barazangi, M., 1986- Deep crustal structure and flexure of the Arabian plate beneath the Zagros collisional mountain belt as inferred from gravity observations, Tectonics, 5, 361–373.
Talebian, M. & Jackson, J., 2002- Offset on the main recent fault of the NW Iran and implications on the late Cenozoic tectonics of the Arabia-Eurasia collision zone, Geophys. J. Int., 150, 422–439.
Talebian, M. & Jackson, J., 2004- A reappraisal of earthquake focal mechanisms and active shortening in the Zagros mountains of Iran, Geophys. J. Int., 156, 506–526.
Tatar, M., Hatzfeld, D. & Ghafory-Ashtiany, M., 2004- Tectonics of theCentral Zagros (Iran) deduced from microearthquake seismicity, Geophys. J. Int., 156, 255–266.J. Int., 156, 255–266.
Tchalenko, J. S. & Braud, J., 1974- Seismicity and structure of the Zagros (Iran)—the Main Recent Fault between 33 and 35.N, Phil. Trans. Roy. Soc. Lond., 277, 1–25.
Tsenn, M. C. & Carter, N. L., 1987- Upper limits of power law creep of rocks. Tectonophysics, 136, 1–26.
Vernant, P. et al., 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.
Vernant, P. J., 2006- Chéry, Mechanical modelling of oblique convergence in the Zagros, Iran. Geophys. J. Int.
Vernant, P. J., Chéry, 2006- Low fault friction in Iran implies localized deformation for the Arabia–Eurasia collision zone, Earth and Planetary Science Letters 246 (2006) 197–206
Yamini-Fard, F., Hatzfeld, D., Tatar, M., 2007- Microearthquake seismicity at the intersection between the Kazerun fault and the Main Recent Fault (Zagros,Iran),Geophys.J. Int. (2006) 166, 186–196 doi: 10.1111/j.1365-246X.2006.02891.x
Yamini-Fard, F., 2007- The diffuse transition between the Zagros continental collision and the Makran oceanic subduction (Iran): microearthquake seismicityand crustal structure, Geophys. J. Int. (2007) 170, 182–194 doi: 10.1111/j.1365-246X.2006.03232.x
Zoth, G., Ha nel, R., 1988- Appendix. In: Ha¨ nel R, Rybach L, Stegena L (eds) Handbook of terrestrial heat flow density determination. Kluwer, Dordrecht, pp 449–466
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