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Article Dans Une Revue Journal of Asian Earth Sciences Année : 2021

Active tectonics along the Khazar fault (Alborz, Iran)

Jean-François Ritz
Mohamadali Shokri
Negar Haghipour
  • Fonction : Auteur
Mehdi Mohammadi Vizheh
  • Fonction : Auteur
Hasan Fazeli Nashli
  • Fonction : Auteur
Mohamadreza Ensani
  • Fonction : Auteur

Résumé

The Alborz Mountain accommodates some of the convergence between Central Iran and Eurasia, is characterized by active range-parallel fold and thrust structures. At present, the kinematics of the range involves a strain partitioning mechanism and clockwise rotation of the South Caspian Basin. Range-parallel, left-lateral strikeslip faulting dominates the central part of the mountain range, while reverse faulting affects its northern and southern borders. Several slip-rate studies have been carried out along active faults in the internal and southern parts of the range. However, the characteristics of the main northern bounding fault (the Khazar [Persian: Caspian] Fault) remain poorly known. Our analysis provides new constraints on the activity of this fault. We first show that the fault generally is a hidden thrust fault, often associated with fault-bend and fault-propagation folds (forebergs). In the central part of the fault, the radiocarbon dating of an uplifted terrace allows estimating minimum vertical and average horizontal slip rates of 2.0 ± 0.5 mm/yr and 3 mm/yr respectively. hence, minimum slip rate along the fault reach to 3.6 mm/yr. About 150 km further east, near the city of Behshahr, within the archeological site of Gohar-Tappe, a paleoseismological trench study on a young detachment foldsuggests that at least 5 events occurred in the past 5,300 years, 3 of them with surface-rupturing between 5300and 3900-years cal BP, our results confirm that the Khazar Fault is a major active structure in northern Iran, and represents a significant seismic hazard for the entire Central Alborz region.
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Dates et versions

hal-03402665 , version 1 (25-10-2021)

Identifiants

Citer

Hamid Nazari, Jean-François Ritz, Jean-Pierre Burg, Mohamadali Shokri, Negar Haghipour, et al.. Active tectonics along the Khazar fault (Alborz, Iran). Journal of Asian Earth Sciences, 2021, 219, pp.104893. ⟨10.1016/j.jseaes.2021.104893⟩. ⟨hal-03402665⟩
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