Present Stress Map and Deformation Distribution in the NE Lut Block, Eastern Iran: Insights from Seismic and Geodetic Strain and Moment Rates

Rashidi, Ahmad; Kianimehr, Hossein; Yaminifard, F.; Tatar, M.; Zafarani, Hamid

doi:10.1007/s00024-022-03015-x

Cited by 13 publications

(7 citation statements)

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“…The seismic/geodetic moment rate is a significant indicator in analyzing to release of more energy [2]. This ratio in the study area with ~0.23 × 10 6 km 2 area is 70.7 which can be compared with the results of the previous studies in the United States [1], Basin and Range [2], the west and south Lut block [3]., and the east and north Lut block [4] (Table 11). The seismic/geodetic moment rate in the area is higher than that of the Basin and Range and the west-south Lut Block where morphotectonic studies emphasize its activity [104][105][106].…”

Section: Analysis Of Geodetic and Seismic Moment Ratesmentioning

confidence: 63%

“…Northern Iran is one of these areas which is home to Iran's capital (Tehran) and more than 23 million people. In this article, we will compare our interpretation of the multidisciplinary data from northern Iran to that from other parts of the world, including the United States [1], Basin and Range [2], the west and south of the Lut block [3], and the NE of the Lut block [4,5].…”

Section: Introductionmentioning

confidence: 99%

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Strain and Moment Rates from GPS and Seismological Data in Northern Iran: Implications for an Evaluation of Stress Trajectories and Probabilistic Fault Rupture Hazard

Rashidi

Derakhshani

2022

Remote Sensing

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This study provides a multi-disciplinary overview of the seismology and geodetic data with tectonics analysis in order to provide an evaluation of stress trajectories, and probabilistic fault rupture hazard assessment. Based on the different scenarios obtained from the comparison of several overviews and their interpretation, we investigated the kinematics and active tectonics of different structural zones. In this study, the magnitudes and directions of seismic and geodetic strain rates (SSR and GSR) were evaluated using reliable earthquake focal mechanisms and all available GPS data (1999–2015) in the structural subzones of northern Iran, where have experienced more than 14 strong instrumental earthquakes (Mw ≥ 6). In addition, a tectonic stress model was inferred from the Focal Mechanism Stress Inversion (FMSI). The new crustal stress map was proposed by the weighted average analysis of the SSR, GSR, and FMSI. N35.5° E and N104° E were estimated for the Alborz and Talesh mountains, respectively. The numerical analysis of stress regimes confirms the slip partitioning mechanism of oblique shortening on the sub-parallel thrusts and strike-slip faults in the area. Four main stress regime categories were defined, including thrust (49.37%), strike-slip (39.24%), thrust with a strike-slip component (2.53%), normal (1.27%), and unknown faulting (7.59%). Seismic and geodetic moment rates (SMR and GMR) and their comparison were also calculated in order to evaluate the function of these parameters in determining the seismicity arrangement. The ratio of the seismic/geodetic moment rates for the area is ~70.7%. This ratio for the Alborz, western Koppeh-Dagh, north part of Central Iran, South Caspian Basin, and Talesh is ~0.9, 0.3, 11.9, 0.3, and 57.3, respectively, which indicates the most elastic energy has been released in the Talesh and the north part of Central Iran. The comparison of geodetic moment rates in the subzones of the area indicates that geodetic deformation is high in the Central Alborz (networks 8, 9, 17) and western Koppeh-Dagh (networks 5, 13).

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Section: Analysis Of Geodetic and Seismic Moment Ratesmentioning

confidence: 63%

Section: Introductionmentioning

confidence: 99%

Strain and Moment Rates from GPS and Seismological Data in Northern Iran: Implications for an Evaluation of Stress Trajectories and Probabilistic Fault Rupture Hazard

Rashidi

Derakhshani

2022

Remote Sensing

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“…These active faults are laterally slipping at a rate of 5.6 ± 0.6 mm/yr and 4.4 ± 0.4 mm/yr, respectively (Walpersdorf et al, 2014). The maximum stress direction (σ1) in the East Iran orogen was determined by the weighted average of the focal mechanism stress inversion, seismic strain rate, and geodetic strain rate at about N36 °E (Nemati and Derakhshani, 2021;Rashidi et al, 2022b). This stress direction is positively correlated with the current mechanism of the faults in the area so that the NS and EW faults, respectively, display dominant rightlateral and left-lateral movements, and the NW-SE faults indicate the reverse movement (Walker and Khatib, 2006;Rashidi et al, 2022c).…”

Section: Tectonic Settingmentioning

confidence: 99%

“…The post-late Cretaceous buckling phases with geodetic strain map of the northern domain of the East Iran orogenic. The current-day strain and stress directions are as a result of the inversions of geodetic and fault slip data, respectively, adapted from (Rashidi et al, 2022b). The focal mechanism stress inversions (FMSI) are based on Sheikholeslami et al (2021) and Rashidi et al (2022b).…”

Section: Figure 17mentioning

confidence: 99%

“…The current-day strain and stress directions are as a result of the inversions of geodetic and fault slip data, respectively, adapted from (Rashidi et al, 2022b). The focal mechanism stress inversions (FMSI) are based on Sheikholeslami et al (2021) and Rashidi et al (2022b). The presented paleo-stress data are from Jentzer et al (2017) and Ezati et al (2022b).…”

Section: Figure 17mentioning

confidence: 99%

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Flexural-slip folding in buckling phases of orogenic belts: Insight into the tectonic evolution of fault splays in the East Iran orogen

et al. 2023

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Introduction: The East Iran orogen has experienced multiple buckling phases resulting in the formation of strike-slip fault splays. The geometric and kinematic characteristics of these splays are influenced by folding mechanisms. This study focuses on investigating the structural characteristics and tectonic evolution model of the Khousf splay, located in the northern terminus of the Nehbandan right-lateral strike-slip fault system.Methods: Field visits and geometrical properties from map views were used to analyze the structural features of the Khousf splay. The splay was found to consist of a multi-plunging anticline and syncline, referred to as the Khousf anticline and Khousf syncline, respectively. Flexural slip was identified as a significant mechanism for the formation of these structures. Structural evidence, including parasitic folds, active folds, and strike-slip duplexes, suggested that flexural slip occurred on discrete movement horizons among the rock units.Results: Analysis of the parasitic folds in the cores and limbs of the Khousf anticline and syncline revealed M, W, Z, and S shapes, with complex slicken-line patterns observed on faults parallel to the beds at the limbs. The analysis results indicated strain partitioning and inclined left- and right-lateral transpressional zones. Shortening estimates obtained from profiles in the Shekarab inclined transpressional zone were approximately 33%, 65%, and 68% for NE-SW, N-S, and NW-SE profiles, respectively. In the Arc area, which is the core of the anticline, shortening estimates from NE-SW and N-S profiles ranged from 14% to 10%. Structural analysis of the folds in this area revealed broad, close, semi-elliptical, and parabolic shapes, suggesting that secondary folds with NW-SE axis directions have been superimposed on the first-generation folds with E-W axis directions in the Khousf refolded splay.Discussion: The findings of this study highlight the structural characteristics and tectonic evolution model of the Khousf splay in the northern terminus of the Nehbandan right-lateral strike-slip fault system. The results suggest that flexural slip played a crucial role in the formation of the multi-plunging anticline and syncline in the Khousf splay. The presence of parasitic folds and complex slicken-line patterns on faults indicate the complexity of deformation processes. The observed strain partitioning and inclined transpressional zones suggest a complex tectonic history in the study area. The superimposition of secondary folds with different axis directions on first-generation folds adds further complexity to the structural evolution of the Khousf refolded splay. Overall, this study provides new insights into the structural characteristics and tectonic evolution of the Khousf splay in the East Iran orogen.

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Tectonic paleostress field and its impact on the geodynamic evolution of Central Iran, case study: the Shotori Mountain

Abbaspour,

Mousavi,

Rashidi

et al. 2023

J. Mt. Sci.

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Present Stress Map and Deformation Distribution in the NE Lut Block, Eastern Iran: Insights from Seismic and Geodetic Strain and Moment Rates

Cited by 13 publications

References 98 publications

Strain and Moment Rates from GPS and Seismological Data in Northern Iran: Implications for an Evaluation of Stress Trajectories and Probabilistic Fault Rupture Hazard

Strain and Moment Rates from GPS and Seismological Data in Northern Iran: Implications for an Evaluation of Stress Trajectories and Probabilistic Fault Rupture Hazard

Flexural-slip folding in buckling phases of orogenic belts: Insight into the tectonic evolution of fault splays in the East Iran orogen

Tectonic paleostress field and its impact on the geodynamic evolution of Central Iran, case study: the Shotori Mountain

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