Dr Esmaeil Shabanian
email: es.shabanian@gmail.com

Ph.D. student; Esmaeil Fariborz Baniadam
email: baniadam@cerege.fr

Olivier Bellier
email: bellier@cerege.fr

The kinematics of the Dasht-e Bayaz earthquake fault during Pliocene

Keywords: fault kinematic analysis, paleostress, active tectonics, Dashte Bayaz Fault, Lut Block, Central Iran Fault kinematic analysis, Paleostress, Active tectonics, Dasht-e Bayaz Fault, Lut Block, Central Iran

The Arabia -Eurasia convergence is accommodated across the Iranian plateau and surrounding mountain ranges. Strike-slip faults play significant roles in the current deformation of the Iranian plateau and were responsible for several moderate to large earthquakes, especially in east of Iran. The sinistral Dasht-e Bayaz fault shows conspicuous seismic and geological activities, while the role of the fault in the accommodation of active convergence is still debated. This paper focuses on the Pliocene-Quaternary to present-day states of stress in the region affected by the Dasht-e Bayaz fault. We applied the fault-slip inversion technique to both kinds of seismologic and geological fault slip data. The inversion results indicate a mean N045±5°E trending σ1 in the modern stress field, which agrees with the present-day tectonic regime (regional N050±05°E trending σ1) deduced from the inversion of earthquake focal mechanism data. The paleostress state is characterized by a N135±15°E trending regional mean σ1, with a transpressional stress regime; E-W faults of the region such as the Dasht-e Bayaz fault were reverse dextral in this paleostress field. We show that the shift in fault kinematics during the Pliocene-Quaternary times has not been restricted to northeastern parts of the Iranian plateau. The cross-cutting relationship between active N-S dextral and E-W sinistral faults indicates a crosswise to conjugate fault arrangement in the middle and the eastern end of the Dasht-e Bayaz fault. Integrating our results at a larger regional scale, we present a kinematic model in which the region between Lut and Kopeh Dagh is divided by the Doruneh fault into two tectonic domains. In the northern domain, active convergence is taken up by the extrusion of fault-bounded crustal blocks while, in the southern domain the convergence is accommodated through crosswise strike-slip faulting accompanied by reverse/thrust faulting in confining wedges.

Introduction

The convergence between Arabia and Eurasia is responsible for current deformation in Iran. Nearly all convergence is accommodated across the Iranian plateau and surrounding mountain ranges such as Zagros, Alborz and Kopeh Dagh; the collision boundaries correspond approximately to the political borders of Iran. The Makran tectonic province is the surface expression of the active subduction of Arabia beneath the Iranian micro-continent (e.g., [START_REF] Walpersdorf | Present-day kinematics and fault slip rates in eastern Iran, derived from 11 years of GPS data[END_REF][START_REF] Burg | Geology of the onshore Makran accretionary wedge: Synthesis and tectonic interpretation[END_REF].

In the recent decades, different parts of the Arabia-Eurasia convergence zone were studied in detail; the pieces of the puzzle of this convergence are progressively fitting together. Numerous studies have attempted to describe the role of strike-slip faults in the active tectonics of the collision zone (e.g., [START_REF] Hessami | Major active faults of Iran[END_REF][START_REF] Karakhanian | Active faulting and natural hazards in Armenia, eastern Turkey and northwestern Iran[END_REF]Talebian and Jackson, 2004;Walker and Jackson, 2004;[START_REF] Regard | Cumulative right-lateral fault slip rate across the Zagros-Makran transfer zone: role of the Minab-Zendan fault system in accommodating Arabia-Eurasia convergence in southeast Iran[END_REF][START_REF] Regard | 10 Be dating of alluvial deposits from Southeastern Iran (the Hormoz Strait area)[END_REF][START_REF] Authemayou | Late Cenozoic partitioning of oblique plate convergence in the Zagros fold-and thrust belt (Iran)[END_REF][START_REF] Meyer | Strike-slip kinematics in Central and Eastern Iran: estimating fault slip-rates averaged over the Holocene[END_REF]Shabanian et al., 2009a[START_REF] Shabanian | New tectonic configuration in NE Iran: active strike-slip faulting between the Kopeh Dagh and Binalud mountains[END_REF]Shabanian et al., and 2012a;;[START_REF] Molnar | Major intracontinental strike-slip faults and contrasts in lithospheric strength[END_REF][START_REF] Farbod | Geomorphic and structural variations along the Doruneh Fault System (Central Iran)[END_REF][START_REF] Farbod | Spatial variations in late Quaternary slip rates along the Doruneh fault system (central Iran)[END_REF][START_REF] Calzolari | Spatio-temporal evolution of intraplate strikeslip faulting: The Neogene-Quaternary Kuh-e-Faghan Fault, central Iran[END_REF][START_REF] Calzolari | Geomorphic signal of active faulting at the northern edge of Lut Block: Insights on the kinematic scenario of Central Iran[END_REF][START_REF] Calzolari | Hematite (U-Th)/He thermochronometry constrains intraplate strike-slip faulting on the Kuh-e-Faghan Fault, central Iran[END_REF]. According to these studies, strike-slip faults play significant roles in the current deformation of the Iranian plateau and were responsible for several moderate to large earthquakes especially in east of Iran (e.g., Dasht-e Bayaz 31 August 1968, Koli-Buniabad 27 November 1979and Zirkuh-Qayen 10 May 1997). Since Pliocene (5.3-2.6 Ma), the dominant tectonic regime in the Iranian plateau and surrounding deformation belts has changed from compressional to strike-slip [START_REF] Regard | Cumulative right-lateral fault slip rate across the Zagros-Makran transfer zone: role of the Minab-Zendan fault system in accommodating Arabia-Eurasia convergence in southeast Iran[END_REF][START_REF] Regard | 10 Be dating of alluvial deposits from Southeastern Iran (the Hormoz Strait area)[END_REF][START_REF] Authemayou | Late Cenozoic partitioning of oblique plate convergence in the Zagros fold-and thrust belt (Iran)[END_REF]Shabanian et al., 2009a[START_REF] Shabanian | New tectonic configuration in NE Iran: active strike-slip faulting between the Kopeh Dagh and Binalud mountains[END_REF][START_REF] Shabanian | Plio-Quaternary stress states in NE Iran: Kopeh Dagh and Allah Dagh-Binalud mountain ranges[END_REF][START_REF] Farbod | Geomorphic and structural variations along the Doruneh Fault System (Central Iran)[END_REF][START_REF] Farbod | Spatial variations in late Quaternary slip rates along the Doruneh fault system (central Iran)[END_REF][START_REF] Ghods | The Varzaghan-Ahar, Iran, Earthquake Doublet (Mw 6.4, 6.2): implications for the geodynamics of northwest Iran[END_REF]Tadayon et al., 2017Tadayon et al., , 2018;;Taghipour et al., 2018). Even in thrust-fold domains such as the Zagros and Alborz belts, where the main way of accommodation of Arabia-Eurasia convergence is crustal shortening, the role of strike-slip faulting is determinant (e.g., Talebian and Jackson, 2004;[START_REF] Authemayou | Late Cenozoic partitioning of oblique plate convergence in the Zagros fold-and thrust belt (Iran)[END_REF][START_REF] Authemayou | Quaternary slip-rates of the Kazerun and the Main Recent Faults: active strike-slip partitioning in the Zagros fold and-thrust belt[END_REF].

The role of major strike-slip faults such as the North Tabriz Fault in northwest Iran (e.g., [START_REF] Cisternas | Seismotectonics of the Mediterranean region and the Caucasus[END_REF][START_REF] Karakhanian | Active faulting and natural hazards in Armenia, eastern Turkey and northwestern Iran[END_REF][START_REF] Ghods | The Varzaghan-Ahar, Iran, Earthquake Doublet (Mw 6.4, 6.2): implications for the geodynamics of northwest Iran[END_REF], the Main Recent Fault in Zagros (Tchalenko et al., 1974;[START_REF] Braud | Eléments de continuité entre le Zagros et la Turquie du Sud-Est[END_REF][START_REF] Ricou | Le Zagros[END_REF][START_REF] Berberian | Natural Hazards and the First Earthquake Catalogue of Iran, Volume 1: Historical Hazards in Iran Prior to 1900[END_REF]Talebian and Jackson, 2004), the Minab-Zendan-Palami fault zone at the Zagros -Makran transition [START_REF] Regard | Cumulative right-lateral fault slip rate across the Zagros-Makran transfer zone: role of the Minab-Zendan fault system in accommodating Arabia-Eurasia convergence in southeast Iran[END_REF] and the Bakharden-Quchan fault system in Kopeh Dagh (Shabanian et al., 2009a[START_REF] Shabanian | New tectonic configuration in NE Iran: active strike-slip faulting between the Kopeh Dagh and Binalud mountains[END_REF] as well as the faults that re-activate the Sistan Suture zone in the east of Iran (e.g., [START_REF] Vernant | Present-day crustal deformation and plate kinematics in the Middle East constrained by GPS measurements in Iran and northern Oman[END_REF]Walker and Jackson, 2004) in accommodation of the Arabia-Eurasia convergence is nearly well-known. These strikeslip faults act as block boundaries along which the blocks are moved in accordance with the overall deformation in the Arabia -Eurasia collision zone (e.g., [START_REF] Walpersdorf | Difference in the GPS deformation pattern of North and Central Zagros (Iran)[END_REF][START_REF] Walpersdorf | Present-day kinematics and fault slip rates in eastern Iran, derived from 11 years of GPS data[END_REF]Tavakoli et al., 2008;[START_REF] Shabanian | New tectonic configuration in NE Iran: active strike-slip faulting between the Kopeh Dagh and Binalud mountains[END_REF][START_REF] Mousavi | Global Positioning System constraints on the active tectonics of NE Iran and the South Caspian region[END_REF][START_REF] Ghods | The Varzaghan-Ahar, Iran, Earthquake Doublet (Mw 6.4, 6.2): implications for the geodynamics of northwest Iran[END_REF].

Recent geodetic (e.g., [START_REF] Vernant | Present-day crustal deformation and plate kinematics in the Middle East constrained by GPS measurements in Iran and northern Oman[END_REF][START_REF] Reilinger | GPS constraints on continental deformation in the Africa-Arabia-Eurasia continental collision zone and implications for the dynamics of plate interactions[END_REF][START_REF] Mousavi | Global Positioning System constraints on the active tectonics of NE Iran and the South Caspian region[END_REF][START_REF] Walpersdorf | Present-day kinematics and fault slip rates in eastern Iran, derived from 11 years of GPS data[END_REF] and geological studies (Shabanian et al., 2009a[START_REF] Shabanian | New tectonic configuration in NE Iran: active strike-slip faulting between the Kopeh Dagh and Binalud mountains[END_REF][START_REF] Shabanian | Plio-Quaternary stress states in NE Iran: Kopeh Dagh and Allah Dagh-Binalud mountain ranges[END_REF](Shabanian et al., , 2012b;;[START_REF] Farbod | Geomorphic and structural variations along the Doruneh Fault System (Central Iran)[END_REF][START_REF] Farbod | Spatial variations in late Quaternary slip rates along the Doruneh fault system (central Iran)[END_REF] in NE Iran have revealed that active deformation is localized along block-bounding crustal faults. In Central Iran, GPS-derived velocity fields [START_REF] Walpersdorf | Present-day kinematics and fault slip rates in eastern Iran, derived from 11 years of GPS data[END_REF] and GPS block modeling [START_REF] Reilinger | GPS constraints on continental deformation in the Africa-Arabia-Eurasia continental collision zone and implications for the dynamics of plate interactions[END_REF][START_REF] Walpersdorf | Present-day kinematics and fault slip rates in eastern Iran, derived from 11 years of GPS data[END_REF] show that about 90 percent of the 5.7 mm/yr northward motion of the Lut block -Eurasia is transferred to the north of the E-W Doruneh fault (Fig. 1).

To the north, the Bakharden-Quchan fault system takes up 4. 1 -4.6 mm/yr of this dextral faulting across the Kopeh Dagh Mountains (Shabanian et al., 2009a[START_REF] Shabanian | New tectonic configuration in NE Iran: active strike-slip faulting between the Kopeh Dagh and Binalud mountains[END_REF](Shabanian et al., , 2012b;;[START_REF] Mousavi | Global Positioning System constraints on the active tectonics of NE Iran and the South Caspian region[END_REF]. In other words, this fault system accommodates 80% of Central Iran-Eurasia convergence (~5.1 mm/yr) north of 37°N. In this tectonic context, there are other strike-slip faults such as the Doruneh and Dasht-e Bayaz faults which affect the Iranian plateau and are characterized by conspicuous seismic and/or geological activities. Nevertheless, the role of these faults in the accommodation of the active convergence has been a matter of debate (e.g., [START_REF] Farbod | Geomorphic and structural variations along the Doruneh Fault System (Central Iran)[END_REF][START_REF] Farbod | Spatial variations in late Quaternary slip rates along the Doruneh fault system (central Iran)[END_REF][START_REF] Nozaem | Post-Neogene right-lateral strike-slip tectonics at the north-western edge of the Lut Block (Kuh-e-Sarhangi Fault), Central Iran[END_REF][START_REF] Calzolari | Spatio-temporal evolution of intraplate strikeslip faulting: The Neogene-Quaternary Kuh-e-Faghan Fault, central Iran[END_REF][START_REF] Calzolari | Geomorphic signal of active faulting at the northern edge of Lut Block: Insights on the kinematic scenario of Central Iran[END_REF][START_REF] Calzolari | Hematite (U-Th)/He thermochronometry constrains intraplate strike-slip faulting on the Kuh-e-Faghan Fault, central Iran[END_REF]Tadayon et al., 2017 and2018). Interestingly, these E-W faults are perpendicular to the N-S active block motions in the Lut and separate the N-S dextral strike-slip faults of the Lut borders (the Nayband and Sistan suture zone) to the south from the NW-trending structures of the Binalud and Kopeh Dagh deformation domains to the north (Fig. 1).

Our understanding of the processes involved in the plate convergence improves progressively, but we still need to know more about (1) both the pattern and kinematics of deformation in each part of the convergence/collision zone and (2) the role of intracontinental crustal faults in the accommodation of this deformation within the plateau. During the last century, areas such as Dasht-e Bayaz, Tabas, and Bam that were considered as stable areas in the interior of rigid blocks have been affected by large destructive earthquakes occurring on mostly unknown faults (e.g., [START_REF] Walker | Insights into the 1968-1997 Dasht-e-Bayaz and Zirkuh earthquake sequences, eastern Iran, from calibrated relocations, InSAR and highresolution satellite imagery[END_REF][START_REF] Berberian | Earthquakes and Coseismic Surface Faulting on the Iranian Plateau[END_REF]. After the destructive 1968 Mw 7.1 earthquake, for instance, the Dasht-e Bayaz area has been one of the most seismically active domains in Iran. Right after the Dasht-e Bayaz main shock in 1968, this area has been studied from different points of view. The first studies focused on mapping of the coseismic rupture and post-earthquake observations (e.g. [START_REF] Ambraseys | The Dasht-e-Bayaz (Iran) earthquake of August 31, 1968: A field report[END_REF]Tchalenko and Ambraseys, 1970;[START_REF] Tchalenko | Dasht-e-Bayaz fault, Iran: earthquake and earlier related structures in bed-rock[END_REF]. Meanwhile, more recent studies have focused on the seismology and the active tectonics of Dasht-e Bayaz and surrounding areas in the context of Arabia-Eurasia convergence (Walker et al., 2004;Walker and Jackson, 2004;[START_REF] Walker | Insights into the 1968-1997 Dasht-e-Bayaz and Zirkuh earthquake sequences, eastern Iran, from calibrated relocations, InSAR and highresolution satellite imagery[END_REF]. However, the main unanswered question regards the role of the E-W sinistral faults such as the Dasht-e Bayaz fault in accommodation of the NNE Arabia -Eurasia convergence (e.g., [START_REF] Vernant | Present-day crustal deformation and plate kinematics in the Middle East constrained by GPS measurements in Iran and northern Oman[END_REF][START_REF] Walpersdorf | Present-day kinematics and fault slip rates in eastern Iran, derived from 11 years of GPS data[END_REF] between Central Iran and Eurasia. This question can be answered partly through an investigation of the temporal and spatial kinematic evolution of the Dasht-e Bayaz fault and its kinematic interaction with other major structures including the Sistan suture zone. It is also important to know whether the stress field in eastern Iran is due to the stress transfer from the Arabia -Central Iran collision, or is influenced by the geometry and relative motion of individual blocks in eastern Iran (e.g., [START_REF] Jentzer | Neogene to Present paleostress field in Eastern Iran (Sistan belt) and implications for regional geodynamics[END_REF]. This paper especially focuses on the Pliocene-Quaternary to present-day states of stress (the last 5 Ma) in the region affected by the Dasht-e Bayaz fault (Fig. 1); the paleo-tectonic evolution of the area is of course out of the scope of this study. We applied the inversion technique on both kinds of fault slip data as provided through focal mechanism of earthquakes and fault measurements in the field, with wellknown senses and relative chronologies. The level of consistency of our results has been discussed in the light of previous studies on the Cenozoic stress field of the Iranian plateau and surrounding deformation belts. We have then put our results in a larger framework, which we have reconstructed using available kinematic data and results from the east and northeast Iran. This has allowed us to discuss the possible interaction of the Dasht-e Bayaz fault with other active faults of the region. Finally, we have proposed a kinematic scenario to describe the role of strike-slip faulting in the accommodation of active convergence in ENE Iran.

Geodynamic and seismotectonic framework

According to geological investigations (e.g., [START_REF] Berberian | The 1997 May 10 Zirkuh (Qa'enat) earthquake (Mw 7.2): faulting along the Sistan suture zone of eastern Iran[END_REF]Walker and Jackson, 2004;Mayer and Le Dortz, 2007;[START_REF] Foroutan | Late Pleistocene-Holocene right slip rate and paleoseismology of the Nayband fault, western margin of the Lut block, Iran[END_REF] and geodetic Global Positioning System (GPS) measurements (e.g., [START_REF] Vernant | Present-day crustal deformation and plate kinematics in the Middle East constrained by GPS measurements in Iran and northern Oman[END_REF][START_REF] Walpersdorf | Present-day kinematics and fault slip rates in eastern Iran, derived from 11 years of GPS data[END_REF], the N-striking right-lateral faults in Central Iran, especially on both sides of the Lut block (Fig. 1), accommodate the northward motion of Central Iran relative to Eurasia (Helmand block in Afghanistan). The Distribution of historic records and instrumental earthquake epicenters, as well as the GPS velocity field show that the convergence is mainly accommodated along the block boundaries, while the interior of the blocks (e.g., Lut block) is almost rigid (e.g., [START_REF] Vernant | Present-day crustal deformation and plate kinematics in the Middle East constrained by GPS measurements in Iran and northern Oman[END_REF]Walker and Jackson, 2004;[START_REF] Walpersdorf | Present-day kinematics and fault slip rates in eastern Iran, derived from 11 years of GPS data[END_REF], with low rates of deformation. The crustal-scale dextral shear continues up to the latitude 34°N, north of which E-W leftlateral faults like the Dasht-e Bayaz, Niazabad and Doruneh (further north) are present (Fig. 1). At this latitude, the change in geology is accompanied by a change in active faulting from the N-S dextral faults of the Sistan suture zone to a system mainly constituted by E-W sinistral strike-slip faults (e.g., [START_REF] Berberian | The 1997 May 10 Zirkuh (Qa'enat) earthquake (Mw 7.2): faulting along the Sistan suture zone of eastern Iran[END_REF]. The role of these crustal faults in the accommodation of active deformation perpendicular to the N-S dextral shear has been a matter of debate since, at least, thirty years ago (e.g. [START_REF] Jackson | Active tectonics of the Alpine-Himalayan belt between Turkey and Pakistan[END_REF][START_REF] Berberian | The 1997 May 10 Zirkuh (Qa'enat) earthquake (Mw 7.2): faulting along the Sistan suture zone of eastern Iran[END_REF]Walker and Jackson, 2004;[START_REF] Farbod | Geomorphic and structural variations along the Doruneh Fault System (Central Iran)[END_REF][START_REF] Farbod | Spatial variations in late Quaternary slip rates along the Doruneh fault system (central Iran)[END_REF][START_REF] Aflaki | The 2017 Mw 6 Sefid Sang earthquake and its implication for the geodynamics of NE Iran[END_REF]. The recent works by [START_REF] Nozaem | Post-Neogene right-lateral strike-slip tectonics at the north-western edge of the Lut Block (Kuh-e-Sarhangi Fault), Central Iran[END_REF], [START_REF] Calzolari | Spatio-temporal evolution of intraplate strikeslip faulting: The Neogene-Quaternary Kuh-e-Faghan Fault, central Iran[END_REF]2016) documented Neogene to Quaternary dextral strike-slip deformation along the NE-SW Kuh-e-Sarhangi and the E-W Kuh-e-Faghan faults and have revealed another complexity in the active kinematics of northwest Lut -Central Iran (Fig. 1). The objective of this part is a brief demonstration of the structural schema and the seismotectonic activity of an active fault network, with complex internal interactions; for this reason we only selected some of the most important and crucial seismic activities in the area without pointing out other subsidiary events that have not been assigned to particular faults.

Active tectonic and seismological studies conducted in Dasht-e Bayaz and the surrounding areas documented that the active faults, responsible for numerous seismic shocks in the area, are temporally and mechanically in close interaction (e.g., [START_REF] Berberian | The 1997 May 10 Zirkuh (Qa'enat) earthquake (Mw 7.2): faulting along the Sistan suture zone of eastern Iran[END_REF]Walker et al., 2004;[START_REF] Walker | Insights into the 1968-1997 Dasht-e-Bayaz and Zirkuh earthquake sequences, eastern Iran, from calibrated relocations, InSAR and highresolution satellite imagery[END_REF].

On 31 August 1968, a tremendous destructive earthquake (Mw 7.1) shocked the area and produced a 70 km E-W coseismic rupture; the maximum coseismic displacement (4.5 m left-lateral and 2.5 m vertical) was measured in north of the Nimboluk plain (Tchalenko and Ambraseys, 1970;[START_REF] Tchalenko | Dasht-e-Bayaz fault, Iran: earthquake and earlier related structures in bed-rock[END_REF]. The formerly called Dasht-e Bayaz fault was renamed later as the western segment of a now longer Dasht-e Bayaz fault, subsequent to the reactivation of its 55 km length extension to the east.

The eastern segment of the Dasht-e Bayaz fault with the same trend and straight geometry attracted attention after 27 November 1979 Mw 7.1 Koli-Buniabad earthquake, only 11 years after the Dasht-e Bayaz main shock (e.g., [START_REF] Berberian | The 1997 May 10 Zirkuh (Qa'enat) earthquake (Mw 7.2): faulting along the Sistan suture zone of eastern Iran[END_REF].

The most remarkable seismic events occurred just 20 hours after the Dasht-e Bayaz main shock during the Ferdows earthquakes of 1st and 4th September 1968 (Mw 6.3 and Mw 5.5, respectively) about 70 km west of the Dasht-e Bayaz village. The close proximity (or even overlap) between the domains of impact of the Dasht-e Bayaz and Ferdows earthquakes has prevented researchers from separating their field effects (e.g., [START_REF] Berberian | Earthquakes and Coseismic Surface Faulting on the Iranian Plateau[END_REF]. Several authors, based on field observations, suggested that the two earthquakes occurred on the NW-trending Ferdows reverse fault (Figs. 1 and2); the reverse focal mechanisms of the earthquakes were also compatible with this fault (see Berberian, 2014 and references therein). After 11 years and during less than one month, three other destructive earthquakes of Korizan (14.11.1979), Koli-Buniabad (27.11.1979-e.g., Haghipour and Amidi, 1980) and Kalateh Shur (07.12.1979-e.g., Haghipour and Amidi, 1980;[START_REF] Ambraseys | A history of Persian earthquakes[END_REF] occurred along the northern part of the Abiz fault, the eastern segment of the Dasht-e Bayaz fault and at the intersection of the two faults, respectively. The Zirkuh earthquake of 1997 May 10 (Mw 7.2), caused by the northern segment of the NNW-striking Abiz fault (Fig. 1), has also been considered as the sequence of seismic events triggered by the Dasht-e Bayaz main shock on 31 August 1968 (e.g., [START_REF] Berberian | The 1997 May 10 Zirkuh (Qa'enat) earthquake (Mw 7.2): faulting along the Sistan suture zone of eastern Iran[END_REF]. The 125-km-long surface faulting which, with dextral strike-slip mechanism has occurred during the Zirkuh earthquake is known as the longest surface rupture associated with an Iranian earthquake (e.g., [START_REF] Berberian | The 1997 May 10 Zirkuh (Qa'enat) earthquake (Mw 7.2): faulting along the Sistan suture zone of eastern Iran[END_REF]. This NNW-striking fault segment changes into a NNE-SSW strike (causative fault of the November 14, 1979 Korizan earthquake; see above) near the eastern end of the Dasht-e Bayaz fault and provides its dextral pair of a conjugate-like arrangement (see section 4; Fig. 3A).

The 1968, 31 August earthquake of Dasht-e Bayaz is considered as a trigger for the reactivation of the east segment of the Dasht-e Bayaz fault, the Ferdows reverse fault zone and the Korizan fault, causing a sequence of earthquakes (e.g. the Zirkuh, Koli-Buniabad and Ferdows earthquakes). The 1968The .09.11, 1979The .01.16 and 1997.06.25 .06.25 events did not rupture the surface (e.g. [START_REF] Berberian | The 1997 May 10 Zirkuh (Qa'enat) earthquake (Mw 7.2): faulting along the Sistan suture zone of eastern Iran[END_REF]. The 1979.01.16 event showed NW-striking reverse faulting and 1997.06.25 event has produced both the possibilities of N-S right-lateral or E-W left-lateral faulting [START_REF] Berberian | The 1997 May 10 Zirkuh (Qa'enat) earthquake (Mw 7.2): faulting along the Sistan suture zone of eastern Iran[END_REF]. The calibrated relocations and the body-wave modeling of [START_REF] Walker | Insights into the 1968-1997 Dasht-e-Bayaz and Zirkuh earthquake sequences, eastern Iran, from calibrated relocations, InSAR and highresolution satellite imagery[END_REF] showed that the epicenter of the 1979.01.16 earthquake is centered on an SW-dipping reverse fault. As for the 1997.06.25 event, [START_REF] Walker | Insights into the 1968-1997 Dasht-e-Bayaz and Zirkuh earthquake sequences, eastern Iran, from calibrated relocations, InSAR and highresolution satellite imagery[END_REF] also proposed that, through InSAR results, the rupture had occurred on the N-S trending dextral fault plane without the possibility to attribute it to any of the Boznabad or Pavak faults (Fig. 2).

Based on this seismicity, it is concluded that the Dasht-e Bayaz and nearby faults are in close kinematic interaction to accommodate the active deformation of the area. This sequence of the Dasht-e-Bayaz, Ferdows andZirkuh earthquakes (occurred between 1968 and[START_REF] Cisternas | Seismotectonics of the Mediterranean region and the Caucasus[END_REF] presents one of the most remarkable examples of temporally clustered continental seismicity in the world (e.g., [START_REF] Berberian | The 1997 May 10 Zirkuh (Qa'enat) earthquake (Mw 7.2): faulting along the Sistan suture zone of eastern Iran[END_REF][START_REF] Walker | Insights into the 1968-1997 Dasht-e-Bayaz and Zirkuh earthquake sequences, eastern Iran, from calibrated relocations, InSAR and highresolution satellite imagery[END_REF]. These consecutive destructive earthquakes could have been triggered by the 31 August 1968 Dasht-e Bayaz main shock (e.g., Berberian et al., 1999 and references therein) and occurred along the faults with different kinematics.

Methodology

Inversion of fault-slip data

Following the method proposed by [START_REF] Carey | Analyse théorique et numérique un modèle mécanique élémentaire appliqué à l'étude d'une population de failles[END_REF], determination of a deviatoric stress tensor from fault slip data is based on the stress-slip relationship described by [START_REF] Wallace | Geometry of shearing stress and relation to faulting[END_REF] and [START_REF] Bott | The mechanics of oblique slip faulting[END_REF]. Computer programs, developed for the inversion of fault slip data, compute a mean best fitting deviatoric stress tensor from a group of striated fault planes by minimizing the angular deviation (misfit angle) between the observed striation and the shear stress resolved on the fault plane [START_REF] Carey | Analyse théorique et numérique un modèle mécanique élémentaire appliqué à l'étude d'une population de failles[END_REF]1979;[START_REF] Angelier | Inversion of field data in fault tectonics to obtain the regional stress. III-a new rapid direct inversion method by analytical means[END_REF]. The inversion results are revised and refined iteratively to reach the smallest misfit angle while involving the highest possible number of measured homogenous fault slip data. The meaningful process of stress determination (deviatoric reduced stress tensor) from both geological and seismological fault slip data is a delicate challenge requiring good quality of data, meticulous observations and data separation as well as adequate knowledge on both kinematics and mechanics of faulting (see [START_REF] Allmendinger | Neotectonic deformation of the southern Puna plateau, NW Argentina[END_REF][START_REF] Shabanian | Plio-Quaternary stress states in NE Iran: Kopeh Dagh and Allah Dagh-Binalud mountain ranges[END_REF][START_REF] Hippolyte | Keys and pitfalls in mesoscale fault analysis and paleostress reconstructions, the use of Angelier's methods[END_REF][START_REF] Tranos | The use of Stress Tensor Discriminator Faults in separating heterogeneous faultslip data with best-fit stress inversion methods[END_REF]. A blind use of abundant computer programs (whatever the software is used) seems very simple, but it would lead to mathematic results without geological significance (see [START_REF] Hippolyte | Keys and pitfalls in mesoscale fault analysis and paleostress reconstructions, the use of Angelier's methods[END_REF]Tranos, 2018 for details).

The method we used is principally invented [START_REF] Carey | Analyse théorique et numérique un modèle mécanique élémentaire appliqué à l'étude d'une population de failles[END_REF][START_REF] Carey-Gailhardis | A numerical method for determining the state of stress using focal mechanisms of earthquake populations: application to Tibetan teleseisms and microseismicity of Southern Peru[END_REF] for the analysis of multiphase heterogeneous fault slip datasets measured in natural fault outcrops which contain a variety of new created and preexisting fault planes reactivated in distinct stress states. This method easily works with both new created conjugate fault pairs and preexisting faults with unknown geometric relationships and is independent of conjugate fault arrangements for resolving reduced stress tensors (see Carey-Gailhardis and[START_REF] Carey-Gailhardis | A numerical method for determining the state of stress using focal mechanisms of earthquake populations: application to Tibetan teleseisms and microseismicity of Southern Peru[END_REF][START_REF] Carey-Gailhardis | Regional state of stress, fault kinematics and adjustments of blocks in a fractured body of rocks: application to the microseismicity of the Rhine graben[END_REF][START_REF] Bellier | Recent state of stress change in the Walker Lane zone, western Basin and Range province, United States[END_REF][START_REF] Regard | Cumulative right-lateral fault slip rate across the Zagros-Makran transfer zone: role of the Minab-Zendan fault system in accommodating Arabia-Eurasia convergence in southeast Iran[END_REF][START_REF] Shabanian | Plio-Quaternary stress states in NE Iran: Kopeh Dagh and Allah Dagh-Binalud mountain ranges[END_REF] for more details). As a main aspect of the program we have used (i.e., FCALC -Geodyn-Soft; [START_REF] Carey-Gailhardis | A numerical method for determining the state of stress using focal mechanisms of earthquake populations: application to Tibetan teleseisms and microseismicity of Southern Peru[END_REF], there is no way for automatic separation of fault slip data and this job have to be done through detailed geological field observations and individual notes on the quality, reliability and chronological relationships (cross-cutting or overprinting) of the structural elements measured in the field, as well as mechanical compatibility of the fault slip data to the resolved stress tensor. Interestingly, the well-known misfit angle, which is an essential criterion for the computer software during the iteration and minimization processes, is the last parameter we consider for the analysis of a heterogeneous fault dataset. This considerably reduces the effect of geologically incompatible slip data in resolving a deviatoric stress tensor. This is simply because an apparently homogenous dataset (separated without reliable geological considerations) could be synthesized through optimizing the misfit angle distribution of the stress model and an arbitrary selection of data mainly based on this criterion. While, that dataset could comprise fault slip data which in reality belong to different tectonic regimes but apparently are compatible with an artificial mean stress tensor resolved from marginal data from those different datasets. Therefore, the misfit angle only shows the level of compatibility of data with a given stress model regardless its geological reliability! Principal inputs are fault-slip data from geological faults measured in the field or seismologically determined focal mechanism of earthquakes including attitudes (e.g., strike/dip/dip quadrant) of striated fault planes and associated striations with well-known sense of movement. As a great advantage, acquisition of field data is feasible almost everywhere and a careful inversion analysis of good quality fault slip data, with known chronological relationships, would lead to a reliable reconstruction of the kinematic history of an area (e.g., [START_REF] Angelier | Tectonic analysis of fault slip data sets[END_REF][START_REF] Carey-Gailhardis | Regional state of stress, fault kinematics and adjustments of blocks in a fractured body of rocks: application to the microseismicity of the Rhine graben[END_REF][START_REF] Hippolyte | Tectonic-stratigraphic record of paleostress time changes in the Oligocene basins of the Provence, southern France[END_REF][START_REF] Bellier | Recent state of stress change in the Walker Lane zone, western Basin and Range province, United States[END_REF][START_REF] Regard | Cumulative right-lateral fault slip rate across the Zagros-Makran transfer zone: role of the Minab-Zendan fault system in accommodating Arabia-Eurasia convergence in southeast Iran[END_REF][START_REF] Shabanian | Plio-Quaternary stress states in NE Iran: Kopeh Dagh and Allah Dagh-Binalud mountain ranges[END_REF]. The main outputs of this method are orientations (trend and plunge) of principal stress axes σ1≥ σ2≥ σ3 (corresponding maximum, intermediate and minimum stresses, respectively) and "R= (σ2-σ1)/(σ3-σ1)". This linear parameter (R) equals 1-φ, φ being another commonly used stress ratio (e.g., [START_REF] Angelier | Determination of mean principal stresses for a given fault population[END_REF][START_REF] Zoback | State of stress and modern deformation of the basin and range province[END_REF][START_REF] Ritz | Revolution stress ellipsoids in brittle tectonics resulting from an uncritical use of inverse methods[END_REF], and describes relative stress magnitudes ranging from 0 to 1 (e.g., [START_REF] Carey | Analyse théorique et numérique un modèle mécanique élémentaire appliqué à l'étude d'une population de failles[END_REF][START_REF] Mercier | Paleostress determinations from fault kinematics: application to the neotectonics of the Himalayan-Tibet and the central Andes[END_REF]Bellier andZoback, 1995, Shabanian et al., 2010 andreferences therein).

Different combinations of Andersonian stress arrangements (vertical principal stress axes of  1 ,  2 and  3 for pure extensional, strike-slip and reverse faulting, respectively) and R values lead to various stress regimes responsible for different kinds of faulting (see [START_REF] Ritz | Revolution stress ellipsoids in brittle tectonics resulting from an uncritical use of inverse methods[END_REF][START_REF] Shabanian | Plio-Quaternary stress states in NE Iran: Kopeh Dagh and Allah Dagh-Binalud mountain ranges[END_REF] for more details). We used the method originally proposed by [START_REF] Carey | Recherche des directions principales contraintes associées au jeu d'une population de failles[END_REF]; the results deduced from inversion of fault-slip data measured in individual sites along the Dasht-e Bayaz fault and nearby areas are presented in Table 1 (see Figs 3 and9 for site locations).

Relative chronology of fault slip data and data separation

According to an important assumption accepted in fault kinematic inversion methods, a distinct stress tensor (σ1≥ σ2≥ σ3 and "R") can create only one slip direction on a given fault plane. The complications of data separation are normally revealed when different sets of heterogeneous fault-slip data are collected from fault planes. Several generations of striae on a single fault plane are surely the result of changes in angular relationships between the fault plane and principal stress axes. Nevertheless, the nature of such changes could either be (1) due to temporal variations in the stress field or (2) could imply the rotation of the fault plane during deformation. In both cases, the chronology of striae is usually determined through the crosscutting relationships of striations and/or fault planes complemented by geological field observations. Except for some probable mistakes in measurements and individual cases of local rotations due to progressive deformation, the fault slip data are usually classified into homogenous sub-groups. In some of related studies, the automatic or semi-automatic methods have also been proposed or utilized to separate heterogeneous fault slip data (e.g., [START_REF] Nemcok | A stress inversion procedure for polyphase fault slip data sets[END_REF]Salvini and Storti,1999;[START_REF] Fry | Striated faults: visual appreciation of their constraint on possible paleostress tensors[END_REF][START_REF] Rossetti | Brittle architecture of the Lanterman Fault and its impact on the final terrane assembly in north Victoria Land, Antarctica[END_REF]Shan et al., 2003;[START_REF] Tranos | TR method (TRM): a separation and stress inversion method for heterogeneous fault-slip data driven by Andersonian extensional and compressional stress regimes[END_REF][START_REF] Tranos | The use of Stress Tensor Discriminator Faults in separating heterogeneous faultslip data with best-fit stress inversion methods[END_REF], however, in this study we preferred to take advantage of techniques concerning data separation based on geological observations and kinematic rules (see [START_REF] Shabanian | Plio-Quaternary stress states in NE Iran: Kopeh Dagh and Allah Dagh-Binalud mountain ranges[END_REF]. Figure 8 shows an example of this strategy which is based on crosscutting relationships, field observations and kinematic considerations. The 10 measurement sites were chosen in outcrops of different stratigraphic ages, ranging from Triassic to Quaternary (Figs 3 and 10); almost half of the measurements (a total number of 170 fault slip data) were done on fault planes affecting Pliocene and Quaternary deposits (see Table 1). Relative chronologies of different generations of striations on a fault plane or in a outcrop has been determined based on the superposition of striations and/or crosscutting relationships between fault planes affecting the outcrop. In a given outcrop, usually, there are few fault planes showing direct chronological indicators for different generations of striations, while the majority of planes only express one direction of striation with unknown relative chronology (see [START_REF] Shabanian | Plio-Quaternary stress states in NE Iran: Kopeh Dagh and Allah Dagh-Binalud mountain ranges[END_REF] for more details). In such the case, fault slip data of different generations have primarily been separated using the well-known relative chronologies observed in the field and then, other compatible fault planes with only one striation were added to each data set based on their kinematic and mechanical compatibilities with the data set, as well as the geological field notes on each fault plane (Fig. 8). The final chronology of the resolved deviatoric stress states (defined as paleo, intermediate or modern stresses) has been determined considering the age of youngest rock units affected by each stress state and chronological cross-relations between different stress tensors.

Certain criteria should be met in order to determine reliable stress solutions (e.g. [START_REF] Etchecopar | Etude des états de contraintes en tectonique cassante et simulation de deformations plastiques (approche mathématique)[END_REF][START_REF] Carey-Gailhardis | Regional state of stress, fault kinematics and adjustments of blocks in a fractured body of rocks: application to the microseismicity of the Rhine graben[END_REF]Belier and Zoback, 1995;[START_REF] Shabanian | Plio-Quaternary stress states in NE Iran: Kopeh Dagh and Allah Dagh-Binalud mountain ranges[END_REF]: ( 1) we need at least 4 fault planes with different attitudes that are well-distributed in the space. A higher number of fault planes and a good spatial distribution will result in a more constrained stress solution, (2) the inversion results will theoretically be reliable when at least 80 percent of deviation angles are under 20°, that means a confidence level of 68 per cent in a Gaussian probability distribution (3) the measured fault planes must show good mechanical compatibility with the stress tensor solution. For instance, a set of transtensional faults cannot be explained by a compressional stress tensor even if output parameters of the tensor to be excellent, (4) a reliable stress solution needs fault slip data of good quality; it greatly depends on the details of field observations, the tectonic history of the measurement site and user's experiences of data measurement and inversion analysis. Considering these criteria, A, B and C were assigned to wellconstrained, constrained and poorly-constrained stress tensor solutions, respectively. For solutions from less than four well-distributed fault planes, we used a fixed solution [START_REF] Bellier | Recent state of stress change in the Walker Lane zone, western Basin and Range province, United States[END_REF] in which, one principal stress axis is fixed as vertical. In this study the quality of fixed solutions has been considered the same as C and they were marked as CF; the stress ratio "R" is not valid for this kind of solutions.

According to the abovementioned method, the measured fault slip data were separated into three homogeneous groups of slip generations and were analyzed. This analysis has provided basic information for describing the last kinematic evolution of the Dasht-e Bayaz fault during the Pliocene and Quaternary times. We compared the pattern of kinematic changes along the Dasht-e Bayaz fault with similar studies in nearby regions in E and NE Iran (e.g. [START_REF] Shabanian | Plio-Quaternary stress states in NE Iran: Kopeh Dagh and Allah Dagh-Binalud mountain ranges[END_REF][START_REF] Farbod | Geomorphic and structural variations along the Doruneh Fault System (Central Iran)[END_REF][START_REF] Javidfakhr | Plio-Quaternary tectonic regime changes in the transition zone between Alborz and Kopeh Dagh mountain ranges (NE Iran)[END_REF][START_REF] Jentzer | Neogene to Present paleostress field in Eastern Iran (Sistan belt) and implications for regional geodynamics[END_REF]Tadayon et al., 2017), which has allowed us to place our results in a larger geodynamic scale (see the discussion).

Inversion of earthquake focal mechanism data

We determined the present-day state of stress in the Dasht-e Bayaz area through the inversion of focal mechanisms of medium to large (7.1>M>5.5) earthquakes applying the method described by [START_REF] Carey-Gailhardis | A numerical method for determining the state of stress using focal mechanisms of earthquake populations: application to Tibetan teleseisms and microseismicity of Southern Peru[END_REF]. These earthquakes have occurred between 1968 and 1997 comprising the Dasht-e Bayaz main shocks. We have only used focal mechanism solutions that had been relocated and modeled using body waves by Walker et al. (2004[START_REF] Walker | Insights into the 1968-1997 Dasht-e-Bayaz and Zirkuh earthquake sequences, eastern Iran, from calibrated relocations, InSAR and highresolution satellite imagery[END_REF]. With this method, we analyzed two orthogonal nodal planes for each earthquake focal solution taking into account that only one plane was reactivated during the earthquake due to the regional stress state. The final selection among each pairs of nodal planes can be done by ( 1) direct observation of the surface rupture of the earthquake, (2) seismological investigations of the rupture process, (3) the spatial distribution of aftershocks and (4) the inverse computation by selecting the nodal plane that results in greater consistency with the regional stress field [START_REF] Carey-Gailhardis | A numerical method for determining the state of stress using focal mechanisms of earthquake populations: application to Tibetan teleseisms and microseismicity of Southern Peru[END_REF]. For determining the regional state of stress, the importance of the main shocks (even a single datum) is significantly greater than that of the aftershocks because small earthquakes would probably reflect kinematic instabilities due to heterogeneous deformation and independent faulting in small-scale bodies (e.g. [START_REF] Carey-Gailhardis | Regional state of stress, fault kinematics and adjustments of blocks in a fractured body of rocks: application to the microseismicity of the Rhine graben[END_REF]. For some of the main shocks, we have direct information on the rupture geometry from field observations (Tchalenko and Ambraseys, 1970;[START_REF] Berberian | The 1997 May 10 Zirkuh (Qa'enat) earthquake (Mw 7.2): faulting along the Sistan suture zone of eastern Iran[END_REF]. This serves as a reference for evaluating the compatibility (in a geometric sense) of other events using inverse computation. This method was successfully applied to determine the causative fault plane of the second event of August 2012 earthquake doublet (Mw 6.4, 6.2), that had occurred in the Ahar-Varzaghan complex fault system in NW Iran (see [START_REF] Ghods | The Varzaghan-Ahar, Iran, Earthquake Doublet (Mw 6.4, 6.2): implications for the geodynamics of northwest Iran[END_REF][START_REF] Momeni | Mainshocks/aftershocks study of the August 2012 earthquake doublet on Ahar-Varzaghan complex fault system (NW Iran)[END_REF][START_REF] Momeni | Mainshocks/aftershocks study of the August 2012 earthquake doublet on Ahar-Varzaghan complex fault system (NW Iran)[END_REF].

Active fault mapping

During the four last decades, several studies have focused on different aspects of the Dasht-e Bayaz earthquake fault providing structural maps of the fault at different scales and at distinct aims (e.g., Tchalenko and Ambraseys, 1970;[START_REF] Tchalenko | Dasht-e-Bayaz fault, Iran: earthquake and earlier related structures in bed-rock[END_REF][START_REF] Walker | Insights into the 1968-1997 Dasht-e-Bayaz and Zirkuh earthquake sequences, eastern Iran, from calibrated relocations, InSAR and highresolution satellite imagery[END_REF]. However, the specific scope of our study on kinematic aspects of the fault and its interaction with other neighboring main faults has led us to prepare a detailed fault map using the high resolution satellite images (Bing images in SAS Planet, http://sasgis.org; 1 m resampled pixel size) of the area. A simplified version of this map is shown in Figure 3, while the more detailed maps are centered on the fault terminations and intersection zones , where additional information are needed to describe the structural characteristics of the Dasht-e Bayaz fault. Thanks to our new fault mapping, we reinterpreted the structural relationships between the main fault and other structures interacting with from the eastern termination westwards along the Dasht-e Bayaz fault (see below).

Active tectonics and structure of the Dasht-e Bayaz fault

The Dasht-e Bayaz fault is a 120-km-long sinistral fault in the north of the Lut block (Fig. 1). The E-W Dasht-e Bayaz fault, with an almost straight geometry, is a structural assemblage of several fault strands with different orientations ranging from N070°E to N110°E (e.g., Tchalenko and Ambraseys, 1970; Fig. 3). This particular structural arrangement forms various contractional and extensional mesoscale structures and the associated morphotectonic landforms such as pull-apart basins, pressure ridges and en-echelon folds at different scales along the fault zone; the same structural patterns were seismically created during the 31 August 1968 Dasht-e Bayaz main shock (Tchalenko and Ambraseys, 1970;[START_REF] Berberian | The 1997 May 10 Zirkuh (Qa'enat) earthquake (Mw 7.2): faulting along the Sistan suture zone of eastern Iran[END_REF]. In addition to these variations in the fault geometry, the Dasht-e Bayaz fault is affected by N-S dextral faults which are in close interaction with the main fault (Figs 3 and4).

At the eastern end, the Dasht-e Bayaz fault intersects the NNE-striking Korizan segment of the Abiz fault (Fig. 3). As an important verified observation, north of 34°N, it is difficult to define any relative dominance for the N-S Korizan or the E-W Dasht-e Bayaz faults while south of this latitude, the N-S dextral faults are dominant and cut both the E-W sinistral and the NW-SE reverse faults of the region (e.g., [START_REF] Berberian | The 1997 May 10 Zirkuh (Qa'enat) earthquake (Mw 7.2): faulting along the Sistan suture zone of eastern Iran[END_REF]. Near the village of Buniabad in the south of Kheybar Kuh-e Kuchek (i.e., Little Kheybar Mountain), these faults join together into a single ENE-WSW trend (Fig. 3). Farther northeast, however, the sinistral Niazabad fault runs parallel to the Dasht-e Bayaz fault and looks like a left-hand stepping segment in a larger E-W sinistral fault system (Fig. 1), which is apparently dominating the N-S dextral fault system of the Sistan suture. The northern parts of the Korizan fault are partly covered by eolian deposits, while the overall fault trace in the south of Buniabad village (Fig. 3) cuts the Quaternary alluvial fan surfaces. Our mapping of the intersection area shows a deforming wedge between the main traces of the Dasht-e Bayaz and Korizan faults (Fig. 3a); the conjugate arrangement of the main faults implies active contraction inside the wedge. Interestingly, N-S fault traces appear again in a discontinuous way in the northern side of the Dasht-e Bayaz fault trace, cutting through Kheybar Kuh-e Kuchek. Except for a few places (see [START_REF] Walker | Insights into the 1968-1997 Dasht-e-Bayaz and Zirkuh earthquake sequences, eastern Iran, from calibrated relocations, InSAR and highresolution satellite imagery[END_REF], the N-S fault strands cut the bedrock and there is no way to evaluate their Quaternary activity. Nevertheless, systematic dextral geomorphic offsets of main streams along these faults could indicate their activity during, at least, the Pliocene time.

Another structural node along the Dasht-e Bayaz fault occurs where it intersects with the N-S Mahyar fault (Fig. 4). In fact, the Mahyar fault (e.g. [START_REF] Berberian | Earthquakes and Coseismic Surface Faulting on the Iranian Plateau[END_REF] separates the western and eastern earthquake segments of the Dasht-e Bayaz fault (ruptures of the 31 August 1968 and 27 November 1979 earthquakes, respectively). Our detailed mapping of the intersection area (Fig. 4) shows that the crosscutting dextral Mahyar fault and the sinistral Dasht-e Bayaz fault form a typical crosswise (nearly orthogonal) fault arrangement in the middle part of the Dasht-e Bayaz fault trace. These coexisting faults have displaced each other in the sense of their movement of about 1.5 km (Figs 3 and4). Following the opposite shear senses of the crosswise faults, double-coupled extensional and contractional domains have been formed in the quarters of this intersection. In the NW and SE extensional quarters, there are two relatively lowlands with an average elevation of 1300 m, while the adjacent NE and SW contractional quarters occupy higher areas with the average elevation of 1400 m (Fig. 4). The NE contractional quarter is occupied by nearly E-dipping reverse faults which join the main trace of the eastern Dasht-e Bayaz fault, southwards (Fig. 4).

In the same area, around the Dasht-e Bayaz and Mahyar faults intersection zone (Fig. 4), different sets of dioritic and andesitic dikes have intruded in folded rocks of Jurassic to Eocene ages [START_REF] Alavi Naini | Geological quadrangle map of Iran, Map K-6, Gonabad sheet[END_REF][START_REF] Fauvelet | Geological quadrangle map of Iran, Map K-7, Qayen sheet[END_REF]. Pliocene deposits cover these post folding dikes and define their stratigraphic age of post Eocenepre Pliocene. We have mapped 379 dikes through the analysis of Bing Map (SAS Planet©) satellite images of the area. The clear crosscutting relationships of the dikes show three generations of which the oldest set (microdioritic dikes;

Mohammadi [START_REF] Mohammadi Gharetapeh | Development of structures in a shear stress regime in East Dasht-e Bayaz Fault Zone (East of Iran)[END_REF] is the most frequent, with a dominant orientation of N330±10°E (Fig. 4). Two younger minor populations of dikes (pyroxene andesitic with N345±15°E and N10±10°E preferred orientations) are less abundant in the area and clearly cut through the oldest generation where coexisted.

Our new mapping of the 1979 earthquake rupture reveals that the main trace of the coseismic rupture dies out westward into a N-S reverse fault zone, with a dextral component of faulting (Figs 4 and5). Other parallel reverse/thrust faults are observed in this quarter, but those haven't been picked up by the coseismic rupture (Fig. 5). In contrast, the adjacent NW extensional quadrant hosts the extensional termination of the 1968 coseismic rupture (Fig. 5). In this area, the E-W trend of the 1968 rupture dies out eastwards into a NE-striking normal fault zone of which a 615-m-long array of surface rupture can be mapped in recent satellite images (Figs 4 and5). The alignment of several SE-facing landslides (with fresh free-faces recognizable on images) along this part of the rupture is coherent with the extensional character of the rupture termination.

Farther west, the Dasht-e Bayaz fault reaches an E-W, pull-apart basin (the Chah Deraz pull-apart basin), which possesses an elongated shape (~3900 m in length and ~870 m in width), with the length to width ratio of 4.5. The almond-shaped geometry of the pull-apart basin, in addition to its symmetric curved boundaries (Fig. 6) implies that the basin was formed in a releasing bend (e.g., [START_REF] Dooley | Analogue modelling of intraplate strike-slip tectonics: A review and new experimental results[END_REF] along the Dasht-e Bayaz fault. Considering the lack of Quaternary activity along the southern border of the basin and the coseismic reactivation of the northern master fault during the 31 August 1968 earthquake (Fig. 6), we suggest that the pull-apart basin has entered a new stage of evolution, by a shift in active extension from the central part to the northwest margin of the basin (Fig. 6).

Further to the west, the Dasht-e Bayaz fault controls the contact between Quaternary deposits and Mesozoic sedimentary rocks. In the north of Nimboluk plain, there are outcrops of Miocene marls armored by Quaternary deposits; the dense cultivation and human-made changes in the Quaternary surfaces, cut by the fault, precluded us from following the trace of the coseismic rupture. The detailed rupture maps of Tchalenko and Ambraseys (1970) and [START_REF] Tchalenko | Dasht-e-Bayaz fault, Iran: earthquake and earlier related structures in bed-rock[END_REF] show that about 12 km westwards from the Chah Deraz pull-apart, the fault trace encounters another structural complexity (Fig. 7). After a 5-km-long en-echelon fracture zone, the main rupture trace turns southwest and continues to the west for ~20 km. This coseismic fault rupture (Mozdabad fault branch) crosses between Dasht-e Bayaz and the Khezri villages and, in the southwest of Mozdabad village, it joins the Ferdows reverse fault array at the western flank of the Kuh-e Kamarkhid and Kuh-e Kalat mountains (Figs. 2 and3).

Interestingly, the main fault trace, visible in the geomorphology of Quaternary alluvial fans, can be directly traced to the west of the Chah Deraz segment, while only a small part of this Quaternary fault has been reactivated during the 1968 earthquake. This branch of the Dasht-e Bayaz geologic fault continues westwards for 13 kilometers, where it bends towards the northwest and joins the north dipping reverse faults in the middle of Kuh-e Kamarkhid (Fig. 2 and7A). In that area, a series of en-echelon pressure ridges and folds have been formed due to a restraining curvature along the Dasht-e Bayaz fault (Fig. 7).

In summary, our new detailed mapping of the Dasht-e Bayaz fault trace and the related structures (thanks to the available very high resolution satellite images and other facilities) reveals that the Dasht-e Bayaz fault is a complex fault zone in which several fault strands with different orientations and kinematics are actively interacting. In this context, N-S dextral and E-W sinistral faults play a significant role in both the structural pattern and active tectonic deformation along the main fault zone.

Fault kinematics and states of stress in the Dasht-e Bayaz area

Modern state of stress

The analysis of the youngest group of fault slip data were measured in ten sites (Table 1, Figs 9 and11) including the last coseismic kinematics of the Dasht-e Bayaz fault (for example, sites 2, 5 and 6 in Figs 10a, 10e-f and 10h, respectively). Except for sites 4, 5b and 6, the maximum stress axis (σ 1 ) has the average trend of N045±5°E (Fig. 13C) and the deviatoric stress tensors indicate a homogenous strike-slip stress field in the area including the Dasht-e Bayaz fault (Figs 9 and 11). The trend of the σ 1 axis locally changes in sites 5b, 6 and 4, with an orientation of ~N070°E (see the section 6.1 for more details).

To avoid local stress changes caused by structural rotations in fault zones and local stresses produced at structural complexities such as fault bends, fault relay zones and fault-bend terminations, we have analyzed together the youngest set of fault-slip data only from main fault planes (MFP) measured over the study area (Figs 10 and 11). A main fault plain is the most prominent structure which controls overall deformation in a given outcrops (for instance, fault planes marked in Figs 10a, 10c, 10f-j) and is usually distinguished from other subsidiary fault planes in the outcrop during field measurements. The inversion analysis of such a particular data set leads to a mean regional stress state responsible for the reactivation of different main fault planes regardless their geographic location and structural setting. The resulting stress tensor specifies a mean regional strike-slip stress regime characterized by a N42±05°E σ 1 axis (Fig. 11). This regional mean σ 1 axis is very close to the average orientation of N45±05°E for the σ 1 that we have independently obtained in 8 individual sites (Fig. 14C). Almost all the stress tensors (except for sites 5A, 6 and 7) were resolved from the analysis of strike-slip fault planes, with pitch angles less than 20° (Fig. 11), showing different dextral or sinistral dominant component of faulting in accordance with their orientation with respect to the principal stress axes (Fig. 11). This strike-slip character is also consistent with the regional mean stress tensor deduced from the inversion of main fault planes (MFP in Fig. 14) and is confirmed by the mean R value of ~0.54 for the tensors with Andersonian strike-slip arrangement (Fig. 11 and Table 1). Accordingly, a prominent pure strike-slip regime is representative for the modern stress field over the study area.

Paleostress state

In 8 sites along the Dasht-e Bayaz fault, we have observed signatures of the oldest generation of fault slip data. These older data, which were naturally fewer than the younger data, were carefully differentiated and analyzed regarding both our field observations and cross-relation of different individual data in each site. For example, our filed observation in site 7 indicates the signature of two distinct deformation stages in Neogene deposits (Figs 8 and 12). A total number of 20 fault planes were measured in site 7. The SE-striking fault planes show an older dextral reverse kinematics (striation 1 in Fig. 8) overprinted by a younger pure reverse kinematics (striation 2 in Fig. 8). The younger fault slip data set is compatible with the modern stress state, while the older data set defines an older reduced stress tensor characterized by a NW-trending maximum compression (Fig. 8C). E-W planes in this data set are oblique-slip dextral reverse faults (right-hand stereogram in Fig. 8C).

In six of eight sites, which are well distributed over the study area, the oldest data sets comprise sufficient data to give independent deviatoric stress tensors (Figs 9 and12; Table 1). These individual stress tensors represent a paleostress state characterized by a homogeneous N135±15°E trending mean σ 1 .

As for the dominant stress regime, except for two stress tensors resolved for sites 6 and 7, the other tensors are fixed solutions, with less than four differently oriented fault planes (see the methodology section). In this case, the tensors cannot be used for determining the stress regime. However, the majority of fault planes analyzed in these paleostress tensors is oblique-slip with a dominant reverse component (Fig. 12) and are coherent with a transpressional stress regime as indicated by the B-Quality tensor 7 in Figure 12. In this paleostress regime, the E-W fault planes, which were measured on the earthquake fault trace of Dasht-e Bayaz or on other faults parallel to it, are oblique-slip reverse dextral faults and show a transpressional character (Fig. 8d).

Intermediate state of stress

In addition to these paleo and modern states of stress, the signature of an intermediate stress field was also measured in three sites along the Dasht-e Bayaz fault (Figs 8, 13; Table 1). This intermediate stress is characterized by a ~N009°E mean σ1 and a strike slip stress regime (Fig. 14B). However, the insufficient number of stress solutions for this stress state precludes us considering it as an independent regional stress field (see the discussion).

The present-day state of stress deducted from inversion of earthquake focal mechanisms

We have used 15 earthquake focal mechanisms that have been recorded in the Dasht-e Bayaz and nearby areas and have been modeled by Walker et al. (2004[START_REF] Walker | Insights into the 1968-1997 Dasht-e-Bayaz and Zirkuh earthquake sequences, eastern Iran, from calibrated relocations, InSAR and highresolution satellite imagery[END_REF] using body wave modeling (Table 2).

The final stress tensor was resolved through the inversion of fault slip data from several earthquakes affecting a vast area around the Dasht-e Bayaz fault and is therefore representative of the present-day regional state of stress in the northern Lut block. This solution indicates a single strike-slip tectonic regime, which characterized by a regional N050±05°E trending σ 1 (Fig. 15) responsible for the active deformation (whatever reverse or strike-slip fault mechanism) throughout the region.

Discussion

Regional versus local stress changes in the Dasht-e Bayaz and close vicinity

In this study, the spatiotemporal changes in the state of stress were investigated through the inversion of fault slip data measured in ten sites along the Dasht-e Bayaz fault. Based on the inversion of independent sets of geologic fault slip data (a N045±05°E compression with strike-slip regime) and earthquake focal mechanisms (a single strike-slip tectonic regime, with a regional N050±05°E trending σ 1 ), the present-day state of stress in the Dasht-e Bayaz area is characterized by a mean regional N050±05°E trending σ 1 accommodated by strike-slip tectonics (Fig. 15). The consistency of these results reveals (1) the absence of remarkable change in the modern state of stress during the late Quaternary time,

(2) the prevalence of a homogeneous stress field in the brittle crust (above the ~17 km depth of seismogenic layer) of the Dasht-e Bayaz region and (3) the lack of stress perturbation due to the activity of the Dasht-e Bayaz fault.

The main strike-slip stress regime deduced along the eastern and middle parts of the Dasht-e Bayaz fault changes into a compressional stress regime at the western end of the fault (sites 6 and 7 in Figures 9 and11). These two distinct stress regimes are coherent with different structural settings of the resolved stress tensors. In fact, despite the strike-slip character of the fault that is clearly expressed along its eastern and central portions (e.g., Tchalenko and Ambraseys, 1970), the kinematics of the Dasht-e Bayaz fault changes to oblique-slip sinistral reverse at its western end. In this area, the strike-slip character of the Dasht-e Bayaz fault disappears near the NW-SE Ferdows thrust [START_REF] Berberian | Zagros, Hindu Kush, Himalaya Geodynamic Evolution[END_REF][START_REF] Berberian | Earthquakes and Coseismic Surface Faulting on the Iranian Plateau[END_REF] where the E-W strike of the fault turns into NW. This change in strike is in accordance with the compressional stress regime obtained from site 7. As for site 6, it is inspected along a pressure ridge formed along a branch of the main fault. In that area, the fault branch locally accommodates the contractional deformation induced by left-lateral faulting along the main fault trend. In other words, this compressional stress regime expresses the local variation in regional stress at structural complexities along the fault. Besides these local changes, the paleostress state deduced from the oldest generation of fault slip data measured in Pliocene and older rock units is characterized by a N135±15°E trending mean σ 1 , with a transpressional stress regime. During the prevalence of this stress field, the E-W Dasht-e Bayaz fault was an oblique reverse dextral fault.

In the kinematic analysis, an important issue is the possibility of structural rotations due to progressive deformation. Evaluating such a possibility, we have used arrays of dikes intruded in the folded strata of the area (section 4; Fig. 4). Aside for the amazing similarity in trends of the oldest generation of dikes (N330±10°E) and the paleo- 1 we have obtained (σ hmax = N315±15°E), the overall orientation of the dikes does not significantly vary along and across the strike of both the Mahyar and Dasht-e Bayaz faults (Fig. 4). The same orientations of the first set of dikes close to, and beyond the main fault traces indicates insignificant structural rotations due to the post injection strike-slip faulting.

Therefore, in the absence of signs of gradual changes in geological markers like post Eocene dikes (see

Late Cenozoic stress fields in the Iranian Plateau, Alborz and Kopeh Dagh mountains

One of the most interesting issues concerning the accommodation of Arabia-Eurasian convergence in the Iranian plateau is the history of the evolution of stress regimes during Pliocene and Quaternary.

Thanks to modern techniques, such as the inversion of focal mechanisms of earthquakes, our knowledge about the present-day state of stress has progressed. Whereas, there is still some ambiguity left concerning the interpretation of long-term changes in stress regime and the transition between successive stress regimes.

Temporal changes in the stress field of the Alborz range, Kopeh Dagh Mountains and north of the Lut block, as well as northwest Iran have been reported by several authors (e.g., Tchalenko et al., 1974;[START_REF] Abbassi | Evolution of the stress field in the Tehran region during the Quaternary[END_REF][START_REF] Jackson | Active tectonics of the South Caspian Basin[END_REF][START_REF] Allen | Accommodation of late Cenozoic oblique shortening in the Alborz range, northern Iran[END_REF][START_REF] Guest | Thermal histories from the central Alborz mountains, northern Iran: implications for the spatial and temporal distribution of deformation in northern Iran[END_REF][START_REF] Zanchi | Inversion tectonics in central Alborz, Iran[END_REF][START_REF] Yassaghi | Influence of a transverse basement fault on along-strike variations in the geometry of an inverted normal fault: case study of the Mosha Fault, Central Alborz Range, Iran[END_REF][START_REF] Abbassi | Faulting and folding in quaternary deposits of Tehran's piedmont (Iran)[END_REF][START_REF] Landgraf | Fault-kinematic and geomorphic observations along the North Tehran Thrust and Mosha Fasham Fault, Alborz mountains Iran: implications for fault-system evolution and interaction in a changing tectonic regime[END_REF][START_REF] Shabanian | Plio-Quaternary stress states in NE Iran: Kopeh Dagh and Allah Dagh-Binalud mountain ranges[END_REF]Shabanian et al., , 2012a;;[START_REF] Farbod | Geomorphic and structural variations along the Doruneh Fault System (Central Iran)[END_REF][START_REF] Javidfakhr | Plio-Quaternary tectonic regime changes in the transition zone between Alborz and Kopeh Dagh mountain ranges (NE Iran)[END_REF]Tadayon et al., 2017;Aflaki et al., 2018aAflaki et al., , 2018b)). The rate and style of deformation in north and northeast Iran have significantly changed during the late Cenozoic (e.g., [START_REF] Ritz | Active transtension inside Central Alborz: a new insight into northern Iran-southern Caspian geodynamics[END_REF][START_REF] Shabanian | New tectonic configuration in NE Iran: active strike-slip faulting between the Kopeh Dagh and Binalud mountains[END_REF][START_REF] Shabanian | Plio-Quaternary stress states in NE Iran: Kopeh Dagh and Allah Dagh-Binalud mountain ranges[END_REF]. The systematic fault kinematics studies in these regions have shown that the late Cenozoic stress changes had been drastic (e.g., [START_REF] Shabanian | Plio-Quaternary stress states in NE Iran: Kopeh Dagh and Allah Dagh-Binalud mountain ranges[END_REF][START_REF] Javidfakhr | Plio-Quaternary tectonic regime changes in the transition zone between Alborz and Kopeh Dagh mountain ranges (NE Iran)[END_REF] As for temporal changes, Tchalenko et al. (1974), during tectonic studies in the Tehran region, have noticed the possible occurrence of a post-Pleistocene change in the orientation of maximum horizontal compression ( 1 ) from NW to NE, based on the pattern of post Eocene dikes, the style of folding and faulting in the alluvial formations. In the same region, Abbassi and Shabanian (1999) have found three distinct states of stress and a clockwise rotation in the stress field through the inversion of fault slip data mostly measured in Pliocene-Quaternary alluviums. According to their research, the oldest stress field was characterized by a NW-trending  1 that has changed into a N-S and then, into a NE-directed maximum compression affecting late Pleistocene to Holocene alluviums. Another interesting research in west-central Alborz [START_REF] Axen | Exhumation of the westcentral Alborz Mountains, Iran, Caspian subsidence, and collision-related tectonics[END_REF], has led to the attainment of the first chronological framework for a major tectonic reorganization in the Alborz Mountains. They have reported a dextral transpressional movement along main faults parallel with the range (between 56 Ma and 7 Ma) before onset (ca. 3.4 Ma) of the modern sinistral faulting on these faults.

In the Kopeh Dagh and Binalud mountains, the inversion of fault slip data measured in 39 sites revealed temporal clockwise changes in the state of stress since 3.6 Ma [START_REF] Shabanian | Plio-Quaternary stress states in NE Iran: Kopeh Dagh and Allah Dagh-Binalud mountain ranges[END_REF]; those include the horizontal σ 1 oriented N140±10°E, N180±10°E and N30±15°E for the paleo, intermediate and modern states of stress, respectively. Similar drastic temporal changes were reported in NNE Iran, including the eastern Alborz and western Kopeh Dagh mountains [START_REF] Javidfakhr | Plio-Quaternary tectonic regime changes in the transition zone between Alborz and Kopeh Dagh mountain ranges (NE Iran)[END_REF]. The analysis of fault slip data in 48 sites led [START_REF] Javidfakhr | Plio-Quaternary tectonic regime changes in the transition zone between Alborz and Kopeh Dagh mountain ranges (NE Iran)[END_REF] to characterize the three homogenous stress fields as the maximum horizontal stress σ 1 orientated N135±20°E (paleostress), N185±15°E (intermediate) and N36±20°E (modern stress) in the transitional zone between the eastern Alborz and western Kopeh Dagh mountains. Farther south, [START_REF] Farbod | Geomorphic and structural variations along the Doruneh Fault System (Central Iran)[END_REF] showed that a Pliocene-Quaternary older state of stress, with a σ 1 orientated N150±20°E, was changed into a modern maximum compression of N45±15°E, responsible for the active sinistral kinematics along the Doruneh fault system.

Other study reveals the same pattern of change in the stress field of northwest Iran (the Mianeh-Mahneshan basin; Aflaki et al., 2018a). The NW-trending fold axes in the Upper Red Formation, folded at the end of Middle Miocene, have been overprinted by two younger generations of NE and NW trending folds in a time interval between Pliocene to Quaternary. The inversion results of fault slip data in this region affirm that a compressional paleostress regime (Pliocene-Quaternary), with a N138°E trending σ 1 , has affected the area before the dominance of the present-day NE-oriented compression.

The recent study in the Sistan belt of eastern Iran [START_REF] Jentzer | Neogene to Present paleostress field in Eastern Iran (Sistan belt) and implications for regional geodynamics[END_REF], however, obtained three distinct deformation stages during late Cenozoic, including ( 1) an E-W (N087±5°E) direction of σ 1 probably in the Late Miocene, (2) a late Pliocene ENE-WSW (N059±8°E) direction of σ 1 and (3) a late Pliocene to present-day maximum compression (N026±8°E). The same authors proposed that during the last ~10-5 Ma, the direction of compression has rotated about 60° counterclockwise in Sistan. The kinematics of this region, especially from the regional geologic and geodynamic points of view, is debatable. However, there is no other similar study in the Sistan belt enabling a comparison and the evaluation of the accuracy of their results.

In summary, even though several studies confirm the occurrence of drastic changes in the dynamics and consequently, in the kinematics of the north, east and northeastern Iran, these results are geographically sparse and need absolute age-based chronologies in order to drawing firm conclusions on the time of dominance and the geodynamic causes of the change in the context of the Arabia -Eurasia convergence.

Integration of our results at the regional scale

After presenting a brief history of the related studies on the evolution of Late Cenozoic stress state in the north, east and northeast of Iran, here, we put our results in a regional tectonic context in order to evaluate the consistency of the results with other similar studies in the north, northwest and west of the Dasht-e Bayaz area.

The results of inversion on both geological and seismological fault slip data indicate the dominance of an active strike-slip tectonic regime characterized by a N45±05°E trending  1 in the Dasht-e Bayaz area. There is a good consistency between this stress regime and the modern state of stress with an average compression of N045°E reported along the Doruneh fault [START_REF] Farbod | Geomorphic and structural variations along the Doruneh Fault System (Central Iran)[END_REF]. Farther north, [START_REF] Shabanian | Plio-Quaternary stress states in NE Iran: Kopeh Dagh and Allah Dagh-Binalud mountain ranges[END_REF] reported a modern state of stress in the Kopeh Dagh and Allah Dagh-Binalud mountains (Fig. 15) characterized by a mean regional ~N030°E trending σ 1 axis. According to the results of [START_REF] Javidfakhr | Plio-Quaternary tectonic regime changes in the transition zone between Alborz and Kopeh Dagh mountain ranges (NE Iran)[END_REF], this modern state of stress prevails on the eastern Alborz and western Kopeh Dagh mountains (mean regional ~N036°E trending σ 1 axis). Interestingly, the results mentioned above cover geological domains with different structural patterns, geological histories and active tectonics, while except for some local perturbations due to structural complexities, the modern state of stress remains homogenous throughout the region.

As for the intermediate stress regime in the Dasht-e Bayaz area, the related maximum horizontal compression obtained in two sites was oriented as ~N009°E. Despite the few number of these stress solutions, at a larger scale, our results are completely in accordance with other studies done in the northeast of Iran (N180±10°E - [START_REF] Shabanian | Plio-Quaternary stress states in NE Iran: Kopeh Dagh and Allah Dagh-Binalud mountain ranges[END_REF][START_REF] Javidfakhr | Plio-Quaternary tectonic regime changes in the transition zone between Alborz and Kopeh Dagh mountain ranges (NE Iran)[END_REF]. Although there is no report of intermediate state of stress by [START_REF] Farbod | Geomorphic and structural variations along the Doruneh Fault System (Central Iran)[END_REF] along the Doruneh fault region, Tadayon et al. ( 2017) presented structural evidences for the prevalence of a penultimate N-S compression during the Plio-Quaternary time (see also Tadayon et al., 2018).

We have obtained a compressional stress regime characterized by a N135±15°E trending mean σ 1 as paleostress state, indicating that the currently left-lateral Dasht-e Bayaz fault had been reverse rightlateral during a certain period of time. As an example, the coseismic rupture of the 1968 earthquake cuts along the main fault trace at the northern border of the Chah Deraz pull-apart (Figs 3 and6). In that area, S-shaped sigmoidal lenses within the fault core (Fig. 10d) indicate an older dextral component for the main fault. A similar paleostress state has been reported in the Kopeh Dagh and the transition zone between the Alborz and Kopeh Dagh mountains (N140±10°E trending σ1 - [START_REF] Shabanian | Plio-Quaternary stress states in NE Iran: Kopeh Dagh and Allah Dagh-Binalud mountain ranges[END_REF][START_REF] Javidfakhr | Plio-Quaternary tectonic regime changes in the transition zone between Alborz and Kopeh Dagh mountain ranges (NE Iran)[END_REF]. A close stress orientation (N150±20°E trending σ1) and structural configuration were also determined along the Doruneh fault [START_REF] Farbod | Geomorphic and structural variations along the Doruneh Fault System (Central Iran)[END_REF]; see also [START_REF] Javadi | History of faulting on the Doruneh Fault System: Implications for the kinematic changes of the Central Iranian Microplate[END_REF][START_REF] Javadi | Tectonic reversal of the western Doruneh Fault System: Implications for Central Asian tectonics[END_REF]Tadayon et al., 2017 and2018). It is worthy to note that farther west, along the Kuh-e Sarhangi and Kuh-e Faghan faults, [START_REF] Nozaem | Post-Neogene right-lateral strike-slip tectonics at the north-western edge of the Lut Block (Kuh-e-Sarhangi Fault), Central Iran[END_REF] and [START_REF] Calzolari | Geomorphic signal of active faulting at the northern edge of Lut Block: Insights on the kinematic scenario of Central Iran[END_REF]2018) have reported a NW-SE directed maximum compression which is responsible for dextral faulting along these faults during the Quaternary time and should not be compared to the paleostress  1 direction we are discussing here.

The general consistency between the results on the kinematic history of the east, northeast and north of the Arabia-Eurasia collision zone [START_REF] Abbassi | Evolution of the stress field in the Tehran region during the Quaternary[END_REF][START_REF] Abbassi | Faulting and folding in quaternary deposits of Tehran's piedmont (Iran)[END_REF][START_REF] Shabanian | Plio-Quaternary stress states in NE Iran: Kopeh Dagh and Allah Dagh-Binalud mountain ranges[END_REF]Shabanian et al., , 2012b;;[START_REF] Farbod | Geomorphic and structural variations along the Doruneh Fault System (Central Iran)[END_REF][START_REF] Javidfakhr | Plio-Quaternary tectonic regime changes in the transition zone between Alborz and Kopeh Dagh mountain ranges (NE Iran)[END_REF][START_REF] Javadi | History of faulting on the Doruneh Fault System: Implications for the kinematic changes of the Central Iranian Microplate[END_REF][START_REF] Javadi | Tectonic reversal of the western Doruneh Fault System: Implications for Central Asian tectonics[END_REF][START_REF] Aflaki | Quaternary state of stress in the Mahneshan-Mianeh sedimentary basin, NW Iran, Scientific quarterly of Geoscience[END_REF]Tadayon et al., 2017Tadayon et al., , 2018;; this study) implies a homogenous transfer of stress during different periods of time, regardless of the geodynamic boundaries. Our results confirm that the Zagros collision zone, and its hinterland domain were mechanically coupled during, at least, late Miocene-Quaternary times (e.g., Tadayon et al., 2018). Such kinds of systematic regional change in the late Miocene to present-day states of stress and kinematics of crustal-scale faults discard the possibility of systematic block rotations around vertical axes in the region between Dasht-e-Bayaz, Doruneh and Kopeh Dagh.

Despite the coherency between our results and those obtained in the northern regions, the history of stress changes along the Dasht-e Bayaz fault differs from what is recently obtained along the Sistan Suture zone [START_REF] Jentzer | Neogene to Present paleostress field in Eastern Iran (Sistan belt) and implications for regional geodynamics[END_REF]. [START_REF] Jentzer | Neogene to Present paleostress field in Eastern Iran (Sistan belt) and implications for regional geodynamics[END_REF] presented different sets of fault slip data related to three successive stress states indicating an anticlockwise rotation in the direction of maximum compression from a Late Miocene E-W directed σ1 to a late Pliocene to present-day maximum compression directed N026±8°E (see the section 6.2 for more details). Their anticlockwise rotation pattern is contrary to the history we found around the Dasht-e Bayaz and Abiz faults.

As for the age, there is no general consensus on the timing of the aforesaid changes in the stress state; for example, according to the morphotectonic analysis along the Mosha and Taleghan faults in Alborz, [START_REF] Ritz | Active transtension inside Central Alborz: a new insight into northern Iran-southern Caspian geodynamics[END_REF] suggested that the change from a N-S compression (compressional tectonic regime) to the present-day NNE-trending compression should have occurred between 1 and 1.5 Ma. Shabanian et al. (2012a) showed geological evidence for late Cenozoic volcanism (dikes and volcanic domes) coeval with the prevalence of the paleostress state (a NW trending maximum compression) in the transition zone between the Kopeh Dagh and Binalud mountains. The last phase of volcanism was dated at 2.4 Ma (Ar-Ar dating of dacitic volcanic domes) and subsequently, a volcanic dome has been rightlaterally displaced by the N-S Chakaneh Fault, reactivated in the modern stress state [START_REF] Shabanian | New tectonic configuration in NE Iran: active strike-slip faulting between the Kopeh Dagh and Binalud mountains[END_REF](Shabanian et al., , 2012a)). Accordingly, they proposed a maximum age of 2.4 Ma (close to the border of Pliocene and Quaternary) for the end of the paleostress prevalence. In the Mahneshan area (NW Iran; Fig. 15), Aflaki et al. (2018a) proposed that the last drastic change in the stress regime into the present-day stress state (a NE trending maximum compression) has taken place at the Pliocene-Quaternary boundary.

Around the Doruneh fault (north of the Lut Block), however, Tadayon et al. ( 2018) suggested that the switch from an early NW-oriented σ 1 to the penultimate N-S maximum compression has occurred at the Miocene-Pliocene boundary (5-6 Ma) and this change has been the source of an important cooling/exhumation in the area.

Nowadays, a drastic change in the Plio-Quaternary tectonic regime throughout the Iranian plateau and the surrounding deformation domains is a geological fact, thanks to different researches carried out during the last two decades (e.g., [START_REF] Abbassi | Evolution of the stress field in the Tehran region during the Quaternary[END_REF][START_REF] Regard | Cumulative right-lateral fault slip rate across the Zagros-Makran transfer zone: role of the Minab-Zendan fault system in accommodating Arabia-Eurasia convergence in southeast Iran[END_REF][START_REF] Shabanian | Plio-Quaternary stress states in NE Iran: Kopeh Dagh and Allah Dagh-Binalud mountain ranges[END_REF]Shabanian et al., , 2012a;;[START_REF] Javidfakhr | Plio-Quaternary tectonic regime changes in the transition zone between Alborz and Kopeh Dagh mountain ranges (NE Iran)[END_REF][START_REF] Farbod | Geomorphic and structural variations along the Doruneh Fault System (Central Iran)[END_REF]Tadayon et al., 2017;[START_REF] Jentzer | Neogene to Present paleostress field in Eastern Iran (Sistan belt) and implications for regional geodynamics[END_REF]Aflaki et al., 2018a). The regional extent of these similar changes in distant Pliocene-Quaternary stress fields clearly discards the possibility of block/stress rotation during progressive deformation. However, the possible causes of change in stress regime, especially in E and N of Iran, remains unclear. This change may be due to the onset of the northward subduction of the South Caspian Basin, and/or changes in the structural configuration or in the lithospheric characteristics of N and NE Iran during an evolving collisional convergence (Shabanian et al., 2012a). In other words, it may correspond to a major regional reorganization of the plate boundary, following the transition from an infant to a mature stage of continental collision (Tadayon et al., 2018).

Tectonic scenario and kinematic model

According to the model frequently applied in the east and northeast of Iran, originally proposed by [START_REF] Jackson | Active tectonics of the Alpine-Himalayan belt between Turkey and Pakistan[END_REF], an uneven distribution of N-S right-lateral shear between Central Iran and Afghanistan and its westward decrease caused a clockwise rotation of fault bounded blocks north of ~34°N (Walker et al., 2004;Walker and Jackson, 2004). The model tends to explain the structural features of the northern Lut block by the concept of clockwise rotation around vertical axes (for the basic assumptions of the model see [START_REF] Farbod | Geomorphic and structural variations along the Doruneh Fault System (Central Iran)[END_REF]. This block rotation model was questioned about its lack of ability in explaining the prominent curvature and the other complexities along the Doruneh Fault System (see Farbod et al., 2011 for detail). For example, [START_REF] Farbod | Geomorphic and structural variations along the Doruneh Fault System (Central Iran)[END_REF], showed that to attain the present-day geometry of the DFS, the fault trace needs to rotate clockwise in the eastern part and counterclockwise in the western part. It is noteworthy that structural deflections and internal deformation, due to local dragging or compression caused by faults or thrust zones, have usually been interpreted as systematic block rotations around vertical axes (e.g., Walker et al., 2004).

The occurrence of pre-Pliocene dextral faulting on E-W trends distributed across Central Iran [START_REF] Javadi | History of faulting on the Doruneh Fault System: Implications for the kinematic changes of the Central Iranian Microplate[END_REF][START_REF] Javadi | Tectonic reversal of the western Doruneh Fault System: Implications for Central Asian tectonics[END_REF][START_REF] Nozaem | Post-Neogene right-lateral strike-slip tectonics at the north-western edge of the Lut Block (Kuh-e-Sarhangi Fault), Central Iran[END_REF][START_REF] Bagheri | Kinematics of the Great Kavir fault inferred from a structural analysis of the Pees Kuh Complex, Jandaq area, central Iran[END_REF][START_REF] Calzolari | Geomorphic signal of active faulting at the northern edge of Lut Block: Insights on the kinematic scenario of Central Iran[END_REF][START_REF] Calzolari | Hematite (U-Th)/He thermochronometry constrains intraplate strike-slip faulting on the Kuh-e-Faghan Fault, central Iran[END_REF]Tadayon et al., 2017) and the Quaternary kinematic shifts along the Doruneh and Dasht-e Bayaz faults [START_REF] Farbod | Geomorphic and structural variations along the Doruneh Fault System (Central Iran)[END_REF][START_REF] Javadi | Tectonic reversal of the western Doruneh Fault System: Implications for Central Asian tectonics[END_REF] this study), which clearly indicate a homogenous regional stress field distribution and coeval evolution of the intracontinental deformation in Central Iran, are not coherent with the block rotation model (see Tadayon et al., 2018 for discussion). The paleomagnetic data of [START_REF] Mattei | Neogene block rotation in Central Iran: Evidence from paleomagnetic data[END_REF] also do not show any systematic clockwise rotation over the Neogene in the region. The most recent study by [START_REF] Mattei | Clockwise paleomagnetic rotations in northeastern Iran: Major implications on recent geodynamic evolution of outer sectors of the Arabia-Eurasia collision zone[END_REF] provides new paleomagnetic data on the Kopeh Dagh. They report that paleomagnetic rotations (the mean of 11.3±9.4° clockwise rotation) occurred in the Kopeh Dagh belt between ~6-4 Ma and ≈2 Ma, before the onset of the westward extrusion of the South Caspian Block. In their studies, [START_REF] Mattei | Oroclinal bending in the Alborz Mountains (northern Iran): new constraints on the age of South Caspian subduction and extrusion tectonics[END_REF]2019) also emphasize that their oroclinal model does not correspond to the present-day kinematics of the studied areas (Alborz and Kopeh Dagh) and the rotation was stopped before the onset of the present-day kinematics at ~2 Ma.

In our tectonic scenario (Figs 16 and 17), right-lateral shear is considered as the main mechanism for the accommodation of the Arabia-Eurasia convergence, but it is not necessarily the case everywhere in E and NE Iran. As for the Lut block, the GPS velocity vectors show a northward (N013°E) block motion with respect to Eurasia [START_REF] Walpersdorf | Present-day kinematics and fault slip rates in eastern Iran, derived from 11 years of GPS data[END_REF]. In the north of latitude of 34°N (corresponding to the E-trending Dasht-e Bayaz fault), the N-S right-lateral shear interrupts and does not continue to the north.

Beyond this latitude, the convergence is mainly accommodated by crustal shortening across NW-trending reverse/thrust faults. The Ferdows reverse fault zone, the Jangal and Khaf thrust faults and the eastern reverse termination of the Doruneh fault [START_REF] Farbod | Geomorphic and structural variations along the Doruneh Fault System (Central Iran)[END_REF] as well as the restraining fault terminations in the southern flank of Binalud (Shabanian et al., 2012b) and the Fariman area [START_REF] Aflaki | The 2017 Mw 6 Sefid Sang earthquake and its implication for the geodynamics of NE Iran[END_REF] are among the most important NW-striking reverse faults confirming our tectonic scenario in northeastern Iran.

To the north and approximately at the latitude 36°N, the right-lateral shear gradually appears along the NE boundary of the Arabia -Eurasia collision zone and involves the NNW-trending faults (instead of the N-S dextral faults to the south) going through the Kopeh Dagh Mountains. The distance between these two fault systems is occupied by a soft-linking restraining relay zone (Binalud-Fariman-Torbat-e Jam; [START_REF] Aflaki | The 2017 Mw 6 Sefid Sang earthquake and its implication for the geodynamics of NE Iran[END_REF] in which the mechanism of faulting is preferably reverse to revers dextral, while farther north in the Kopeh Dagh, it is pure dextral strike-slip. In other words, the N-S right-lateral shear between Iran and Afghanistan that had been interrupted in the latitude 34° N (corresponding to the Dashte Bayaz fault) is recuperated gradually around the latitude of ~36°N, but this time along the NW-trending faults and against the Turan platform instead of the Helmand block (Afghanistan).

The integrated geological, seismological and InSAR investigations done by [START_REF] Aflaki | The 2017 Mw 6 Sefid Sang earthquake and its implication for the geodynamics of NE Iran[END_REF], in the area affected by the 5th April 2017 Sefid Sang earthquake (Mw 6), showed that the dextral shear along the NNW-striking faults (i.e., Bakharden-Quchan and Hezar Masjed fault systems) is transferred southeast into WNW-striking transpressional terminations in the region between the Binalud Mountains and Doruneh fault (Fig. 17). The CMT and the first polarity solutions of the main shock and the two aftershocks of this seismic event, which occurred close to the southern termination of the Hezar Masjed fault system near the town of Fariman (Fig. 15), indicate a mainly reverse mechanism with a small dextral component (See Aflaki et al., 2019 for details). This event clearly reveals the dominance of reverse faulting in the southeastern end of Kopeh Dagh and the eastern termination of the Doruneh fault.

In summary, we suggest that the outstanding changes in the structural pattern of these regions are the cause of a significant change in the accommodation mechanism of convergence. It means major fault zones in the E and NE Iranian regions guide and control lithospheric block motions and their related velocity fields. In the offset and/or overlapping areas of these major fault zones the convergence is accommodated by internal deformation and shortening through reverse/thrust faulting and active folding (e.g., [START_REF] Farbod | Geomorphic and structural variations along the Doruneh Fault System (Central Iran)[END_REF][START_REF] Aflaki | The 2017 Mw 6 Sefid Sang earthquake and its implication for the geodynamics of NE Iran[END_REF]. For instance, the pure strike-slip Doruneh fault becomes a typical reverse fault at its eastern end parallel to the other NW-trending reverse faults such as Ferdows, Khaf and Jangal. In this context the role of E-W sinistral faults such as the Doruneh, Dasht-e Bayaz and Niazabad faults can be explained through their setting in the regional structural pattern.

The Khaf and Jangal thrusts have been considered as probable sources for the Zuzan historical destructive earthquakes [START_REF] Berberian | Earthquakes and Coseismic Surface Faulting on the Iranian Plateau[END_REF] of 19 and 21 October of 1336 A.D., respectively. The 1 and 4 September 1968 Ferdows earthquakes (M W 6.8 and M W 5.5) also indicate significant tectonic activity of these reverse fault zone. The study of magnetic foliation vertical and oblique to the bedding of post Miocene folds in the Ferdows fault zone [START_REF] Rashid | Late folding-related magnetic foliation in the active Ferdows (northeastern Iran) thrust-fold system[END_REF] suggests that a cleavage system, not visible at the outcrop scale, has been developed as a consequence of recent shortening related to the activity of this thrust zone. All these observations reveal that, in the northern Lut, the NW-trending reverse/thrust fault zones accommodates substantial portion of the active deformation perpendicular to their strikes. The E-W strike-slip faults such as the Dasht-e Bayaz and Niazabad faults therefore retain their complementary role in the crustal shortening between these thrust zones (Fig. 2). It is worth mentioning that our kinematic model generally describes the northeastern border of Arabia-Eurasia collision zone and clearly it does not include the distant regions such as the eastern Alborz and internal blocks of Central Iran. Summarizing all these observations on both the structural configuration and the present-day relative velocity field (Eurasia fixed) in east-northeast Iran, the Doruneh fault is a major boundary separating two distinct northern and southern domains (Fig. 16). Angular relationships between N-S dextral and E-W sinistral faults obviously change in these tectonic domains such that the northern domain is characterized by NNW-striking dextral and ENE-striking sinistral faults (e.g., [START_REF] Tchalenko | Dasht-e-Bayaz fault, Iran: earthquake and earlier related structures in bed-rock[END_REF]Shabanian et al., 2009a[START_REF] Shabanian | Plio-Quaternary stress states in NE Iran: Kopeh Dagh and Allah Dagh-Binalud mountain ranges[END_REF][START_REF] Javidfakhr | Plio-Quaternary tectonic regime changes in the transition zone between Alborz and Kopeh Dagh mountain ranges (NE Iran)[END_REF], while, N-S dextral, E-W sinistral and NW-SE reverse/thrust faults are dominant in the southern domain. These different structural patterns lead to (1) the NNW extrusion of both Central Iran and western Kopeh Dagh towards the South Caspian Basin [START_REF] Hollingsworth | Strike-slip faulting, rotation and along-strike elongation in the Kopeh Dagh Mountains, NE Iran[END_REF][START_REF] Shabanian | New tectonic configuration in NE Iran: active strike-slip faulting between the Kopeh Dagh and Binalud mountains[END_REF] However, the simultaneous activity of these crosswise fault sets is mechanically impossible; therefore, the fault sets must be operating in sequence (e.g., [START_REF] Freund | Kinematics of transform and transcurrent faults[END_REF]. The sequence of recent seismic activities, producing sinistral faulting along both the western and eastern segments of the Dasht-e Bayaz fault and right-lateral faulting in the south of this system, could confirm this interaction (see [START_REF] Berberian | The 1997 May 10 Zirkuh (Qa'enat) earthquake (Mw 7.2): faulting along the Sistan suture zone of eastern Iran[END_REF][START_REF] Walker | Insights into the 1968-1997 Dasht-e-Bayaz and Zirkuh earthquake sequences, eastern Iran, from calibrated relocations, InSAR and highresolution satellite imagery[END_REF]. This active crosswise faulting also leads to the development of contractional (reverse/thrust) fault zones perpendicular to the overall direction of Arabia -Eurasia convergence accommodating two northward and eastward components of the convergence (Fig. 17).

We emphasize that this tectonic scenario is based on different geological and seismological observations (this study and the references cited above) on the eastern and northeastern boundaries of the Arabia -Eurasia convergence zone. We do not apply this scenario to kinematic complexities reported in other places in Central Iran. For example, dextral faulting along the Kuh-e Sarhangi and Kuh-e Faghan faults in the northwest margin of the Lut block [START_REF] Nozaem | Post-Neogene right-lateral strike-slip tectonics at the north-western edge of the Lut Block (Kuh-e-Sarhangi Fault), Central Iran[END_REF][START_REF] Calzolari | Geomorphic signal of active faulting at the northern edge of Lut Block: Insights on the kinematic scenario of Central Iran[END_REF]2018) has been explained as a consequence of an excess dextral shear generated in the intrafault block bordered by the Doruneh fault to the north and the Dasht-e-Bayaz fault to the south. In this context, the Ferdows reverse fault zone partly accommodates internal deformation of the intrafault block [START_REF] Nozaem | Post-Neogene right-lateral strike-slip tectonics at the north-western edge of the Lut Block (Kuh-e-Sarhangi Fault), Central Iran[END_REF].

At first glance to our tectonic scenario, one may make a similar conclusion by assuming a component of westward extrusion for the northern block of the Dasht-e Bayaz fault. However, deducing such the conclusion needs detailed information on the difference of slip rates on the Doruneh and Dasht-e Bayaz faults as well as the contribution of the Ferdows reverse fault zone in the accommodation of this differential slip rate. Our observations indicate that the kinematic changes during the Pliocene -Quaternary times have not been restricted to the northeastern part of the Iranian plateau. The general consistency between the results on the kinematic history of the east, northeast and north of the Arabia -Eurasia collision zone implies that a homogenous transfer of stress during, at least, late Miocene -Quaternary times, has taken place due to the mechanical coupling of the Zagros collision and its hinterland domains.

Conclusion

We suggest that the region between Lut and Kopeh Dagh is divided by the Doruneh fault into two northern and southern distinct tectonic domains. The northern domain is characterized by the extrusion of fault-bounded blocks towards the north-northwest, while in the southern domain, the northward motion of the central Iranian blocks occurs through structural and kinematic interactions between N-S dextral, E-W sinistral and NW-striking reverse/thrust faults at the block boundaries without a need for symmetric block rotations around vertical axes. [START_REF] Bellier | Recent state of stress change in the Walker Lane zone, western Basin and Range province, United States[END_REF]. Numbers on top left of stereograms refer to site marked in Figure 9 as well as in Table 1. MFP refers to result of inversion of major fault plane data. 1. Numbers on top left of stereograms refer to site marked in Figure 9 as well as in Table 1. The stereograms indicated by asterisk are the "fixed" solutions [START_REF] Bellier | Recent state of stress change in the Walker Lane zone, western Basin and Range province, United States[END_REF] for fault data populations comprised of less than four well-distributed fault directions. See the caption of Figure 11 for stereoplot descriptions. 1. Numbers on top left of stereograms refer to site marked in Figure 9 as well as in Table 1. See the caption of Figure 11 for stereoplot descriptions. [START_REF] Marrett | Kinematic analysis of fault-slip data[END_REF][START_REF] Allmendinger | Structural geology algorithms: Vectors and tensors in structural geology[END_REF]. Blue and red arrows indicate the mean direction of σ 1 and σ 3 , respectively. earthquakes that have been modeled using body waves (Walker et al., 2004), see the caption of Table 2 for more details. We put into practice inversion of focal mechanisms by using moderate to large earthquakes (7.1>M>5.7) and employing the method proposed by [START_REF] Carey-Gailhardis | A numerical method for determining the state of stress using focal mechanisms of earthquake populations: application to Tibetan teleseisms and microseismicity of Southern Peru[END_REF].

Figure 4 )

 4 Figure4), our results indicate a drastic change in the regional state of stress and in other words, a

  and (2) block translation and internal deformation through crosswise strike-slip faulting accompanied by reverse/thrust faulting in confining wedge in the north and south of the Doruneh fault, respectively. The details of these different processes are shown in Figure 17. The process of wedge confining at the edges of north-going blocks (Fig. 17a; due to a NE-trending compression) allows accommodating the internal deformation not absorbed by the lithospheric scale northwards motion of Central Iran relative to Eurasia. The block adjustment requiring for the accommodation of this internal deformation is done through crosswise faulting along N-S dextral and E-W sinistral faults (Fig. 17b-d). The active crosswise pattern of the faults and the almost symmetrical deformation in the four quadrants around their intersection zones (Figs 4 and 17) indicate the same structural significance for the N-S and E-W faults.

  Our inversion analysis of fault kinematics data revealed signatures of three distinct stress fields in the Dasht-e Bayaz area during Plio-Quaternary. Before the onset of the active left-lateral faulting along the Dasht-e Bayaz fault, an old stress state characterized by a N135±15°E trending σ 1 was responsible for the dextral transpressional movements. The consistency between the inversion results of both modern geological fault slip data and the earthquake focal mechanisms reveals: (1) the absence of remarkable change in the modern state of stress during the late Quaternary time, (2) the prevalence of a homogeneous stress field in the brittle crust (above the ~17 km depth of seismogenic layer) of the Dasht-e Bayaz region and (3) the lack of long-term stress perturbation due to the activity of the Dasht-e Bayaz fault.

FiguresFigure 1 .

 1 Figures

  Figure 1. General tectonic map of the east and northeastern Iran. (A) The location of the study area (blue rectangle) in the Arabia-Eurasia collision framework (after Shabanian et al., 2010). Grey arrows and associated numbers represent Arabia-Eurasia plate velocities (mm/yr) after Reilinger et al. (2006). Solid lines are boundaries of plates or major blocks. (B) GTOPO30 topographic image showing the regional tectonic setting and the major active faults (red lines) in E and NE Iran. The study area of Dashte Bayaz is marked by the black dashed rectangle. Reverse/thrust faults are marked by small triangles pointing to the fault hanging wall. The fault map is based on[START_REF] Hessami | Major active faults of Iran[END_REF],Walker and Jackson (2004),[START_REF] Shabanian | Plio-Quaternary stress states in NE Iran: Kopeh Dagh and Allah Dagh-Binalud mountain ranges[END_REF][START_REF] Farbod | Geomorphic and structural variations along the Doruneh Fault System (Central Iran)[END_REF][START_REF] Nozaem | Post-Neogene right-lateral strike-slip tectonics at the north-western edge of the Lut Block (Kuh-e-Sarhangi Fault), Central Iran[END_REF],[START_REF] Calzolari | Spatio-temporal evolution of intraplate strikeslip faulting: The Neogene-Quaternary Kuh-e-Faghan Fault, central Iran[END_REF] and this study.

Figure 2 .

 2 Figure 2. Map of the major active faults around the Dasht-e Bayaz area. (A) Major fault zones and their structural interactions in the area of interest. Focal mechanism solutions belong to the major earthquakes of the study area (redrafted from waveform modeling of Walker et al., 2004 and 2011). (B) LANDSAT ETM satellite overview (RGB, 541) of the area emphasizing the western termination of the left-lateral Dasht-e Bayaz, Kabutarkuh and Avash faults.

Figure 3 .

 3 Figure 3. Simplified geological map of the Dasht-e Bayaz area based on published geological maps of the area (Alavi Naini and Behruzi, 1983; Fauvelet and Eftekhar Nezhad, 1991). Fault traces were extracted from satellite images complemented by field observations; we used Tchalenko and Berberian (1975) maps for the co-seismic ruptures in the northern Nimboluk plain, which currently is under cultivation.

Figure 4 .

 4 Figure 4. Morpho-structural map of the central intersection zone along the Dasht-e Bayaz fault. (A) Detailed fault map of the interaction zone of the Mahyar and the Dasht-e Bayaz faults. Solid black line is geological fault; inferred fault is shown by dashed black line. Red solid line is the coseismic rupture of the Dasht-e Bayaz 1968 (west of the Mahyar fault) and 1979 (east of the Mahyar fault) earthquakes. The N-S dextral and E-W sinistral fault zones displaced each other in the sense of their movement of about 1.5 km; see Figure 17 for more details on the structural configuration of this zone. The lower right rose diagram (rosette) indicates the frequency of orientations of post-folding dikes (cut by strike-slip faults) concentrated around the intersection zone; note that the overall orientation of N330±10°E does not significantly vary along the strike-slip faults. Two topographic profiles across the contractional (P1) and extensional (P2) quadrants are shown.

Figure 5 .

 5 Figure 5. Bing Map image (SAS.Planet© 2015-2017) centered on the western termination of the East Dasht-e Bayaz fault. See Figure 3 for location. (A) Detailed fault map of the area. Solid white lines are coseismic rupture traces and dashed white lines are geological faults not reactivated during the 1979 Dasht-e Bayaz earthquake. (B) Close-up view of the sinistral rupture that terminates in a NE-dipping reverse segment. (C) Close-up view of the northern end of the reverse fault segment due to intersection with a SW-trending sinistral segment.

Figure 6 .

 6 Figure 6. SPOT image of the Chah Deraz pull-apart basin along the west Dasht-e Bayaz fault. (A) the active trace of the fault passes at the northern margin of the basin, while the southern one is inactive. (B) close-up view of the coseismic rupture (1968 Dasht-e Bayaz earthquke) at the northen margin of the basin.

Figure 8 .

 8 Figure 8. Distinct fault slips related to the modern and intermediate states of stress and a summary of data separation strategy applied in this study. (A) SE looking field photograph a fault plane (site 7) that includes two generations of striations and (B) a stereoplot of these striations. (1) and (2) refer to older and younger relative chronologies, respectively, of the striations on the fault plane in the Neogene mudstone. This site is along the western end of the Dasht-e Bayaz fault where it merges the Ferdows reverse fault zone. (C) The schmidt lower hemisphere stereographic projection of the fault slip data measured in site 7. (D) The lower hemisphere stereographic projection of the fault slip data measured in site 3. The middle diagram is non-separated data set including all fault slip data. (1) and (2) refer to the older and younger relative chronology of the striations. The stereograms (1) and (2) indicate relative chronology of two distinct sets of data. The relative chronology of striations is according to cross-cutting relationships observed on fault planes (colored as red). This strategy is applied to other sites for separation of fault slip data into homogenous data sets.

Figure 9 .

 9 Figure 9. Reconstruction of the Plio-Quaternary stress fields in the Dasht-e Bayaz area, the base is ASTER image (RGB, 321). Direction of Maximum horizontal stress axis (σ1) for different stress fields showing dominant stress regimes including strike-slip, compressional and extensional deducted from inversions of fault kinematics data in each sites (seeTable 2). (A) Modern state of stress (B) Intermediate state of

  ). (A) Modern state of stress (B) Intermediate state of stress (C) Paleostress state of stress.

Figure 10 .

 10 Figure 10. Field photographs of some of sites we have inspected for the measurement of fault slip data along the Dasht-e Bayaz fault. (a) Site 2 at the northern margin of the Chah Deraz pull-apart basin. (b) A northwards view of the fault plane and the associated sinistral striation in site 2. (c) general view of the Dashte-Bayaz earthquake rupture to the west of the intersection zone. (d) structural evidence of an ancient dextral faulting along the main trace of the Dasht-e Bayaz fault in the Chah Deraz pull-apart basin. (e) and (f) fault plane and striation of the fault measured along the coseismic rupture. (g) An outcrop of the northern continuation of the Korizan fault in site 1. (h) The reverse-sinistral fault trace in Neogene deposits in site 6. (i) a fault plane with two distinct generation of striations in site 10. (j) a metric scale sinistral fault plane along the main fault zone in site 9.

Figure 11 .

 11 Figure 11. Lower hemisphere stereograms of fault slip data with inversion results of the modern state of stress presented in Table 1. Fault planes and measured slip vectors (arrows on fault planes) are plotted. Large arrows outside stereograms represent the direction of minimum (σ3, divergent, white arrows) and maximum (σ1) horizontal stress axes. Histograms show distribution of deviation angles between the measured and calculated slip vectors (e.g.,

Figure 12 .

 12 Figure 12. Lower hemisphere stereograms of fault slip data with inversion results of the paleostress state presented in Table 1. Numbers on top left of stereograms refer to site marked in

Figure 13 .

 13 Figure 13. Lower hemisphere stereograms of fault slip data with inversion results of the intermediate state of stress presented in Table 1. Numbers on top left of stereograms refer to site

Figure 14 .

 14 Figure 14. Lower hemisphere stereograms showing statistical analysis of the preferred direction of the maximum horizontal stress axis (σ 1 ) corresponding to (A) paleostress state (N135 ±15°E), (B) intermediate state of stress (N009±10°E) and (C) modern state of stress (N45±05°E); all calculated in PBT axes method[START_REF] Marrett | Kinematic analysis of fault-slip data[END_REF][START_REF] Allmendinger | Structural geology algorithms: Vectors and tensors in structural geology[END_REF]. Blue and red arrows

Figure 15 .

 15 Figure 15. Stress map of the Iranian plateau and surrounding mountain belts. (A) S H max orientations deriving from some of earthquake focal mechanisms in the Iranian plateau created by online stress map creator: http://www.world-stress-map.org/casmo/ (see Heidbach et al., 2016 and references therein). Abbreviation is: TF, thrust faulting; SS, strike-slip; NF, normal faulting; U, unknown; B, Binalud; KD, Kopeh Dagh; EA, eastern Alborz; WA, western Alborz; MT, Meshkan transition zone; F, Fariman town; SB, Sistan belt; Za, Zagros; M, Mosha; T, Taleghan; MM, Mahneshan -Mianeh . Different tectonic regimes are characterized by different symbol colors. NF and NS data is printed in red, SS data in green, and TF and TS data in blue. Data with an unknown regime is printed in black. (B) Our inversion results (N050±05°E trending σ 1 ) showing the presentday state of stress in Dasht-e Bayaz area, source parameters were used from instrumentally recorded

Figure 16 .

 16 Figure 16. A brief explanation of our model about the northern Lut block and the southern Kopeh Dagh domain. (A) Up to latitude 34° N the majority of convergence is accommodated by rightlateral shear between Iranian plateau and fixed Eurasia. To the north of latitude 34° N, an interruption in right-lateral shear takes place and in the absence of right-lateral shear, convergence is accommodated by reverse/thrust faulting. (B) Schematic model emphasizing the role of separated thrust zones, as confining wedges at the termination of N-S dextral fault, in accommodation of the Arabia-Eurasia convergence. See text for more information.

Figure 17 .

 17 Figure 17. Details on the processes involved in the accommodation of Lut -Eurasia convergence in the NE and E Iranian regions. (A) The process of wedge confining at the edges of north-going blocks and the associated secondary sinistral faulting along E-W faults such as the Dashte Bayaz and Niazabad. The overall N013°E direction of Lut -Eurasia motion (Walpersdorf et al., 2014) is mainly taken up by lithospheric N-S dextral shear translating the southern tectonic domain (STD) northwards. Shortening at the opposing edges of the main blocks (STD against ER) is accommodated through reverse faulting in a restraining relay zone (RRZ in "A"; Farbod, 2012; Aflaki et al., 2019), while internal deformations due to sub-block adjustments is taken up by crosswise dextral and sinistral faulting accompanied by contractional deformation at their terminations (CW, confining wedge); BBFS, Bakharden -Binalud fault system; DF, Doruneh fault; DBF, Dasht-e Bayaz fault. (B) And (C) Site-scale examples for the evolution of crosswise faulting; (B) illustrates the initial stage of crosswise faulting and (C) shows the structural configuration of crosswise dextral and sinistral faults after development of contractional quadrants. "TL" is the length of the main thrust fault zone developed perpendicular to the compression and is proportional to the amount of dextral (DD) and sinistral (SD) displacements of the main crosswise fault traces. (D) The intersection zone between the Dasht-e Bayaz and Mahyar faults; note to the analogy between this structural configuration and the typical crosswise faulting illustrated in (C). Such kind of kinematic interaction accommodates the overall convergence oblique to the faults without a need for rotations of faults and blocks around vertical axes.

Acknowledgements

We would like to thank to Mr. Koreie and Mr. Fotovati from Geological Survey of Iran for their support and logistic assistance. We are grateful to municipality of Khezri-Dasht-e Bayaz and Sangan Iron Ore Complex for their support during field trips. We thank Mr. Lhôte and the staff of French Embassy in Tehran. We appreciate to A. Ghods and F. Sobouti in Institute for Advanced Studies in Basic Sciences in Zanjan. Very careful and insightful reviews by Federico Rossetti and two anonymous reviewers have greatly improved the manuscript. We are indebted to Editor Ling Chen for handling the manuscript.

Research Data Related to this Submission

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 Shan, J., Suen, H., and G. Lin (2003), Separation of polyphase fault/slip data: an objective function algorithm based on hard division, J. Struct. Geol.,25,[829][830][831][832][833][834][835][836][837][838][839][840] Tadayon, M., Rossetti, F., Zattin, M., Nozaem, R., Calzolari, G., Madanipour, S., and F. Salvini (2017),

The post-Eocene evolution of the Doruneh Fault region (Central Iran): The intraplate response to the reorganization of the Arabia-Eurasia collision zone, Tectonics,36, Tadayon, M., Rossetti, F., Zattin, M., Calzolari, G., Nozaem, R., Salvini, F., Faccenna, C., and P. Khodabakhshi (2018), The long-term evolution of the Doruneh Fault region (Central Iran): A key to understanding the spatio-temporal tectonic evolution in the hinterland of the Zagros convergence zone, Geological Journal, 1-26, doi:10.1002/gj.3241. Taghipour, K., Khatib, M.M., Heyhat, M.R., Shabanian, E., and A. Vaezihir (2018), Evidence for distributed active strike-slip faulting in NW Iran: The Maragheh and Salmas fault zones, Tectonophysics, 742, 15-33. Talebian, M., and J. Jackson (2004), A reappraisal of earthquake focal mechanisms and active shortening in the Zagros mountains of Iran, Geophys. J. Int., 156, 506-526. Tavakoli, F., Walpersdorf, A., Authemayou, C., Nankali, H.R., Hatzfeld, D., Tatar, M., Djamour, Y., Nilforoushan, F., and N. Cotte (2008), Distribution of the right-lateral strike-slip motion from the Main Recent Fault to the Kazerun Fault System (Zagros, Iran): Evidence from present-day GPS velocities, Earth Planet. Sci. Lett, 275, 342-347, doi:10.1016/j.epsl.2008.08.030. Tchalenko, J.S., and N.N. Ambraseys (1970), Structural analysis of the Dasht-e Bayaz (Iran) earthquake fractures, Geol. Soc. Am. Bull., 81, 41-60. Tchalenko, J.S., Braud, J., and M. Berberian (1974), Discovery of three earthquake faults in Iran, Nature, 248, 661-663. Note: Site numbers and their geographic coordination refer to Figure 9. The results of inversion of fault slip data are including trend and plunge of principal stress axes (σ1, σ2, σ3 (matching maximum, intermediate and minimum stress axes, respectively) and stress ratio "R= (σ2-σ1) / (σ3-σ1)" shows the relative stress magnitude. N, number of fault slip data involved in stress calculations; Rm points out to stress regimes: C, compressional; S, strike-slip; Q indicates the quality of stress tensors: A, well-constrained; B, constrained; C, poorly-constrained solutions. CF quality represents data sets consist of less than four spatially well-distributed fault slip data, for this kind of data sets a "fixed" solutions [START_REF] Bellier | Recent state of stress change in the Walker Lane zone, western Basin and Range province, United States[END_REF] is used, in which the principal stress axes were fixed to lie in horizontal and vertical planes. In site 5, two deviatoric stress tensors (5A and 5B) were obtained. Note: In this research we used the source parameters of instrumentally recorded earthquakes in the Dasht-e Bayaz region that have been modeled by Walker et al. (2004) with body wave methods. References are the same as they used in their modeling, including: ( 1) Baker ( 1993), ( 2) [START_REF] Berberian | The 1997 May 10 Zirkuh (Qa'enat) earthquake (Mw 7.2): faulting along the Sistan suture zone of eastern Iran[END_REF], (3) [START_REF] Walker | Thrust faulting in eastern Iran: source parameters and surface deformation of the 1978 Tabas and 1968 Ferdows earthquake sequences[END_REF], ( 4) Jackson ( 2001) and ( 5) Walker et al. (2004). An (m) after of some of Mw means a multiple event. For more information see Table 1 of [START_REF] Walker | Insights into the 1968-1997 Dasht-e-Bayaz and Zirkuh earthquake sequences, eastern Iran, from calibrated relocations, InSAR and highresolution satellite imagery[END_REF]. Note: Site numbers and their geographic coordination refer to Figure 9. The results of inversion of fault slip data are including trend and plunge of principal stress axes (σ1, σ2, σ3 (matching maximum, intermediate and minimum stress axes, respectively) and stress ratio "R= (σ2-σ1) / (σ3-σ1)" shows the relative stress magnitude. N, number of fault slip data involved in stress calculations; Rm points out to stress regimes: C, compressional; S, strike-slip; Q indicates the quality of stress tensors: A, well-constrained; B, constrained; C, poorly-constrained solutions. CF quality represents data sets consist of less than four spatially well-distributed fault slip data, for this kind of data sets a "fixed" solutions [START_REF] Bellier | Recent state of stress change in the Walker Lane zone, western Basin and Range province, United States[END_REF] is used, in which the principal stress axes were fixed to lie in horizontal and vertical planes. In site 5, two deviatoric stress tensors (5A and 5B) were obtained. Note: In this research we used the source parameters of instrumentally recorded earthquakes in the Dasht-e Bayaz region that have been modeled by Walker et al. (2004) with body wave methods. References are the same as they used in their modeling, including: (1) Baker (1993), (2) [START_REF] Berberian | The 1997 May 10 Zirkuh (Qa'enat) earthquake (Mw 7.2): faulting along the Sistan suture zone of eastern Iran[END_REF], (3) [START_REF] Walker | Thrust faulting in eastern Iran: source parameters and surface deformation of the 1978 Tabas and 1968 Ferdows earthquake sequences[END_REF], (4) Jackson ( 2001) and ( 5) Walker et al. (2004). An (m) after of some of Mw means a multiple event. For more information see Table 1 of [START_REF] Walker | Insights into the 1968-1997 Dasht-e-Bayaz and Zirkuh earthquake sequences, eastern Iran, from calibrated relocations, InSAR and highresolution satellite imagery[END_REF].