Scientific Quarterly Journal of Geosciences

Scientific Quarterly Journal of Geosciences

New Paleoseismological Results within the Overlap Zone of NW and SE Segments of North Tabriz Fault (NW Iran)

Document Type : Original Research Paper

Authors
A. Fathian Baneh 1
S. Solaymani Azad 2
H. Nazari 3
M. Ghorashi 4
M. Talebian 3
1 Mastert of Science, Basic Science Faculty, Islamic Azad University, North Tehran Branch, , Tehran, Iran.
2 Ph.D., Geological Survey of Iran, Tehran, Iran.
3 Assistant Professor, Research Institute for Earth Sciences, Geological Survey of Iran, Tehran, Iran
4 Associate Professor, Basic Science Faculty, Islamic Azad University; North Tehran Branch; Research Institute for Earth Sciences, Geological Survey of Iran, Tehran, Iran
10.22071/gsj.2012.54048
Abstract
Tabriz city, the most highly population city of NW Iran, is located close to the North Tabriz Fault (NTF). This 150 km right-lateral strike-slip fault consists of two major fault segments arranged in right-stepping pattern. A pull-apart basin has been formed within the overlap zone of these fault segments due to the recent right-lateral motion. The basin margins mark by fault branches and fault splays, which connect these two major segments of NTF. High level historical earthquakes occurrence shows seismic activity of NTF. Among which, NTF is responsible of at least two destructive earthquakes occurred in 1721 A.D. (Ms 7.3) and 1780 A.D. (Ms 7.4). This fault has not experienced any strong seismic events since 1780 A.D. Within past decades, it has been tried to recognize large number of old earthquakes utilizing paleoseismological investigation. Previous paleoseismological studies have been focused on the NW and SE segments of the fault. In the present study, to complete the data sets necessary to assess the seismic hazard related to Tabriz city, we focus on overlap zone of the two main fault segments. Using aerial photos, satellite images and field investigations, a potential site has been recognized within the zone (6 km NW of Tabriz City) to perform paleoseismological studies. Trench opened perpendicular to fault scarp strike and focused paleoseismological investigations in that, show evidences of at least two macroseismic events.
Keywords
NW Iran
North Tabriz Fault
Paleoseismology
Overlap zone
Fault splays
 
References
Ambraseys, N. N. & Melville, C. P., 1982- A History of Persian Earthquakes, Cambridge Earth Science Series, Cambridge University Press, London.
Berberian, M. & Arshadi, S., 1976- On the evidence of the youngest activity of the North Tabriz Fault and the seismicity of Tabriz city, Geol. Surv. Iran Rep., 39, 397-418.
Berberian, M., 1997-  Seismic sources of the Transcaucasian historical earthquakes. In: Giardini, D., Balassanian, S. (Eds.), Historical and Prehistorical Earthquakes in the Caucasus. Kluwer Academic Publishing, Dordrecht, Netherlands, pp. 233–311.
Berberian, M. & Yeats, R. S., 1999- Patterns of historical earthquake rupture in the Iranian plateau, Bull. Seismol. Soc. Am., 89, 120-139.
Copley, A. & Jackson, J., 2006-  Active tectonics of the Turkish-Iranian Plateau, Tectonics, Vol. 25, TC6006, doi:10.1029/2005TC001906.
Hessami, K., Pantosi, D., Tabassi, H., Shabanian, E., Abbassi, M., Feghhi, K., Sholaymani, S., 2003-  Paleoearthquakes and slip rates of the North Tabriz Fault, NW Iran: preliminary results, Ann. Geophys. 46, 903–915.
Hessami, K. & Jamali., F., 2008- New evidence of earthquake faulting in the Tabriz city, NW Iran, Geoscience, vol 17, No. 1, pp. 156-161.
Jackson, J. A., 1992-  Partitioning of strike-slip and convergent motion between Eurasia and Arabia in Eastern Turkey and the Caucasus, J. Geophys. Res. 97, 12471-12479.
Karakhanian, A., Trifonov, V., Philip, H., Avagyan, A., Hessami, K., Jamali, F., Bayraktutan, M., Bagdassarian, H., Arakelian, S., Davtyan, V. & Adilkhanyan, A., 2004-  Active faulting and natural hazards in Armenia, eastern Turkey and Northern Iran, Tectonophysics, 380, 189–219.
Masson, F., Djamour, Y., Van Gorp, S., Chery, J., Tatar, M., Tavakoli, F., Nankali, H. & Vernant, P., 2006-  Extension in NW Iran driven by motion of the South Caspian Bosin, Earth Planet. Sc. Lett., 252, 180–188.
McCalpin, J. P., 2009- Paleoseismology, Academic Press, New York.
Nilforoushan, F., Masson, F., Vernant, P., Vigny, C., Martinod, J., Abbassi, M., Nankali, H., Hatzfeld, D., Bayer, R., Tavakoli, F., Ashtiani, A., Doerflinger, E., Daignières, M., Collard, P. & Chéry, J., 2003- GPS network monitors the Arabia- Eurasia collision deformation in Iran, J. Geody., 77, 411–422.
Solaymani Azad, S., 2009- Evaluation de l'alea sismique pour les villes de Tehran, Tabriz et Zandjan dans le NW de l’Iran approche morphotectonique et paleosismologique, Université Montpellier II (France), 151 p.
Vernant, P., Nilforoushan, F., Hatzfeld, D., Abbassi, M., Vigny, C., Masson, F., Nankali, H., Martinod, J., Ashtiani, A., Bayer, R., Tavakoli, F. & Chery, J.,  2004- Contemporary crustal deformation and plate kinematics in Middle East constrained by GPS measurement in Iran and northern Oman, Geophys. J. Int., 157, 381–398.
Vernant, P. & Chery, J., 2006- Low fault friction in Iran implies localized deformation for the Arabia-Eurasia collision zone, Earth Planet. Sci. Lett., 246, 197-206.
Vittori, E., Labini, S. S. and Serva, L., 1991- Paleoseismology: Review of the state-of-the-art. Tectonophysics, 193, 9-32.
Westaway, R., 1990- Seismicity and tectonic deformation rate in Soviet Armenia: implications for local earthquake hazard and evolution of adjacent regions, Tectonics, 9, 477-503.
Scientific Quarterly Journal of Geosciences
Volume 22, Issue 86
Autumn 2012
Pages 3-12