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Papers by Behzad Zamani g.

Research paper thumbnail of Recent tectonics of East (Iranian) Azerbaijan from stress state reconstructions

Tectonophysics, 2014

Iranian (East) Azerbaijan (E-Azerbaijan), in northwestern Iran, is characterized by relatively co... more Iranian (East) Azerbaijan (E-Azerbaijan), in northwestern Iran, is characterized by relatively complex active tectonics. The area is shaped like a lozenge and is bordered by strike-slip faults. This region includes three fold and thrust belts, the Arasbaran, Ghoshe Dagh and Bozkosh mountain ranges, and includes a set of N-S trending compressive thrusts and folds and a set of E-W trending compressive structures. The stress inversion analysis and separation of stress tensors performed in this study indicates that the region is characterized by N-S to NE-SW (N018°) thrusting compression and NW-SE (N287° and N155°) strike-slip compression. The first stress system was responsible for the development of the three fold and thrust belts, while the second system formed the N-S striking structures, such as those in the Talesh, Salavat, Moro and Kiamaki Ranges. The stress reconstructions indicate that E-Azerbaijan is colliding with the South Caspian Basin and the Lesser Caucasus in the NE and N due to the compressive stress (S2) and with the Central Iranian Block and western Alborz in the southeast and east, respectively, due to the strike-slip stress mode (S3 and S1, respectively).

Research paper thumbnail of Analysis of Neo-Tectonic Stress State of Zagros Orogeny and Separation of Stress Regimes by Earthquake Data

فصلنامه علمی علوم زمین, Jun 1, 2015

Research paper thumbnail of Finite element modeling of tectonic stress field of Iran based on geodetic and seismic data

Acta Geodynamica et Geomaterialia, 2017

In this paper, the tectonic stress field of Iran studied by a two-dimensional elastic finite elem... more In this paper, the tectonic stress field of Iran studied by a two-dimensional elastic finite element model (FEM) using inverse modeling technique. Using the named method, the relative magnitude of the tectonic forces and the regional parameters of the major blocks estimated. Geodetic and stress analysis results used for evaluating and validating the results of the developed inverse model. This developed model allows estimating the effect of different parameters of the stress pattern. The results denote that the direction of convergence plays an important role in distribution of the stress pattern, and the shape of the plate boundary is the main factor in controlling the shape of the distribution of the maximum compressional stress. The results also show that the magnitude of the maximum principal stress axes (δ1) reduce from the west and southwest to the north and northeast of Iran. The maximum stress magnitude is dominantly in the NW-Zagros, Azarbaijan, Qatar-Kazeron, Kope-Dagh, Zabol block and Lut block, while western part of Iran shows a thrusting mode stress state.

Research paper thumbnail of Experimental tectonic modelling of East (Iranian) Azerbaijan, inferred from stress pattern

Modeling Earth Systems and Environment, 2017

Research paper thumbnail of State of stress in the northern Tabas block, east-central Iran, as inferred from focal mechanisms of the 1978 Tabas earthquake sequence

Central European Journal of Geosciences, 2011

In this paper, the state of stress in the northern Tabas block in east-central Iran is analyzed b... more In this paper, the state of stress in the northern Tabas block in east-central Iran is analyzed based on the systematic inversion of aftershock focal mechanisms from the 1978.09.16 Tabas earthquake, to characterise the stress regime that controls most earthquakes in this area. Here, stress inversions of double-couple focal mechanisms of earthquakes recorded during the 30 days following the main shock have been carried out. The calculated average stress regime indicates dominant major 226° to 237° trending compression for the Tabas region. The dominating regime in east-central Iran is thrusting with a minimum stress axis, σ 3, close to vertical. The reconstruction of the main seismotectonic stress in east-central Iran with a NE-SW compression is consistent with independent information of the active plate convergence related to Arabia-Eurasia convergence. Most earthquakes in the mentioned area occur near or around concealed Quaternary thrust faults with their activity being controlled...

Research paper thumbnail of State of stress induced by plate convergence and stress partitioning in northeastern Iran, as indicated by focal mechanisms of earthquakes

Journal of Geodynamics, 2008

We analyse the state of stress in northeastern Iran, based on systematic inversion of available f... more We analyse the state of stress in northeastern Iran, based on systematic inversion of available focal mechanisms of earthquakes. The calculated average stress regimes in this area indicates major N32 • E trending compression expressed in reverse and strike-slip focal mechanisms, consistent with the plate convergence in Iran that shows clockwise deflection with respect to Arabia-Eurasia convergence. A secondary stress regime is reliably characterised from our stress inversion, with a N172 • E trending compression expressed in focal mechanisms of predominant strike-slip type. Whereas the NNE-SSW and N-S compressions coexist in the western Kopet Dagh, East Alborz and the northwestern Doruneh fault zone, where the structural grain trends ENE-WSW, the N-S compression is absent in the eastern and central Kopet Dagh, Binalud and northeastern Doruneh fault zone, where the structural grain trends ESE-WNW, perpendicular to relative motion. This configuration reveals stress partitioning involving oblique compression with significant along-belt component of left-lateral shear to the west, in contrast to typical belt-perpendicular compression in the eastern sub-area.

Research paper thumbnail of InSAR analysis of the coseismic deformation of the August 11th, 2012 Ahar-Varzaghan (NW Iran) earthquakes (Mw 6.4 and 6.3)

Research paper thumbnail of Recent tectonics of East (Iranian) Azerbaijan from stress state reconstructions

Tectonophysics, 2014

Iranian (East) Azerbaijan (E-Azerbaijan), in northwestern Iran, is characterized by relatively co... more Iranian (East) Azerbaijan (E-Azerbaijan), in northwestern Iran, is characterized by relatively complex active tectonics. The area is shaped like a lozenge and is bordered by strike-slip faults. This region includes three fold and thrust belts, the Arasbaran, Ghoshe Dagh and Bozkosh mountain ranges, and includes a set of N-S trending compressive thrusts and folds and a set of E-W trending compressive structures. The stress inversion analysis and separation of stress tensors performed in this study indicates that the region is characterized by N-S to NE-SW (N018°) thrusting compression and NW-SE (N287° and N155°) strike-slip compression. The first stress system was responsible for the development of the three fold and thrust belts, while the second system formed the N-S striking structures, such as those in the Talesh, Salavat, Moro and Kiamaki Ranges. The stress reconstructions indicate that E-Azerbaijan is colliding with the South Caspian Basin and the Lesser Caucasus in the NE and N due to the compressive stress (S2) and with the Central Iranian Block and western Alborz in the southeast and east, respectively, due to the strike-slip stress mode (S3 and S1, respectively).

Research paper thumbnail of Analysis of Neo-Tectonic Stress State of Zagros Orogeny and Separation of Stress Regimes by Earthquake Data

فصلنامه علمی علوم زمین, Jun 1, 2015

Research paper thumbnail of Finite element modeling of tectonic stress field of Iran based on geodetic and seismic data

Acta Geodynamica et Geomaterialia, 2017

In this paper, the tectonic stress field of Iran studied by a two-dimensional elastic finite elem... more In this paper, the tectonic stress field of Iran studied by a two-dimensional elastic finite element model (FEM) using inverse modeling technique. Using the named method, the relative magnitude of the tectonic forces and the regional parameters of the major blocks estimated. Geodetic and stress analysis results used for evaluating and validating the results of the developed inverse model. This developed model allows estimating the effect of different parameters of the stress pattern. The results denote that the direction of convergence plays an important role in distribution of the stress pattern, and the shape of the plate boundary is the main factor in controlling the shape of the distribution of the maximum compressional stress. The results also show that the magnitude of the maximum principal stress axes (δ1) reduce from the west and southwest to the north and northeast of Iran. The maximum stress magnitude is dominantly in the NW-Zagros, Azarbaijan, Qatar-Kazeron, Kope-Dagh, Zabol block and Lut block, while western part of Iran shows a thrusting mode stress state.

Research paper thumbnail of Experimental tectonic modelling of East (Iranian) Azerbaijan, inferred from stress pattern

Modeling Earth Systems and Environment, 2017

Research paper thumbnail of State of stress in the northern Tabas block, east-central Iran, as inferred from focal mechanisms of the 1978 Tabas earthquake sequence

Central European Journal of Geosciences, 2011

In this paper, the state of stress in the northern Tabas block in east-central Iran is analyzed b... more In this paper, the state of stress in the northern Tabas block in east-central Iran is analyzed based on the systematic inversion of aftershock focal mechanisms from the 1978.09.16 Tabas earthquake, to characterise the stress regime that controls most earthquakes in this area. Here, stress inversions of double-couple focal mechanisms of earthquakes recorded during the 30 days following the main shock have been carried out. The calculated average stress regime indicates dominant major 226° to 237° trending compression for the Tabas region. The dominating regime in east-central Iran is thrusting with a minimum stress axis, σ 3, close to vertical. The reconstruction of the main seismotectonic stress in east-central Iran with a NE-SW compression is consistent with independent information of the active plate convergence related to Arabia-Eurasia convergence. Most earthquakes in the mentioned area occur near or around concealed Quaternary thrust faults with their activity being controlled...

Research paper thumbnail of State of stress induced by plate convergence and stress partitioning in northeastern Iran, as indicated by focal mechanisms of earthquakes

Journal of Geodynamics, 2008

We analyse the state of stress in northeastern Iran, based on systematic inversion of available f... more We analyse the state of stress in northeastern Iran, based on systematic inversion of available focal mechanisms of earthquakes. The calculated average stress regimes in this area indicates major N32 • E trending compression expressed in reverse and strike-slip focal mechanisms, consistent with the plate convergence in Iran that shows clockwise deflection with respect to Arabia-Eurasia convergence. A secondary stress regime is reliably characterised from our stress inversion, with a N172 • E trending compression expressed in focal mechanisms of predominant strike-slip type. Whereas the NNE-SSW and N-S compressions coexist in the western Kopet Dagh, East Alborz and the northwestern Doruneh fault zone, where the structural grain trends ENE-WSW, the N-S compression is absent in the eastern and central Kopet Dagh, Binalud and northeastern Doruneh fault zone, where the structural grain trends ESE-WNW, perpendicular to relative motion. This configuration reveals stress partitioning involving oblique compression with significant along-belt component of left-lateral shear to the west, in contrast to typical belt-perpendicular compression in the eastern sub-area.

Research paper thumbnail of InSAR analysis of the coseismic deformation of the August 11th, 2012 Ahar-Varzaghan (NW Iran) earthquakes (Mw 6.4 and 6.3)