A model suggests the current shear, which originated about 5 Ma ago, has been accommodated by strike-SLIP faulting within and along the margins of the Lut area. The measured Quaternary SLIP RATE along the Nehbandan fault system to the east and the Nayband fault system to the west margins of the Lut area is ~ 5 and ~ 1.7±0.3 mm/year, respectively. Therefore, the observed SLIP RATE is shown to increase from west to the east margin. This has resulted in the development of a dextral strike-SLIP shear system with heterogeneous SLIP RATE across the Lut area. We have used satellite images, field observations, aeromagnetic data and analogue modeling to measure Cenozoic strain distribution and SLIP-RATE changes in the Lut area. Results show direct linkage between deformation distribution and SLIP RATE changes along the margins of the Lut area.

In previous decades, using traditional geodetic observations such as distance and angle measurements was prevalent in the earth surface displacement studies. After accessing to satellite positioning systems with a high precision ability such as GPS, we encountered to an upheaval in the earth surface displacement studies. Indeed using temporal variations of the earth surface deformation, the seismotectonics of the area can be distinguished. Deformation modeling of the area can be accessed using the analyzing of repeated geodetic measurements. In Tehran area the earthquake studies is an important task and in this paper we are going to use GPS measurements for this field. Here 35 GPS stations cover whole of Tehran which consists North Tehran fault. These stations were occupied at least 2 annual epochs and some of them were measured more than 4 times. After processing the acquired data and analyzing the results, the velocity field was obtained. Deformation analysis of the velocity field shows a small left lateral movement about 0.5-2 mm/year and more or less the same value for shortening in the northern band Tehran area. This value is not constant along the northern band and it seems the eastern part where we reach the Mosha fault the deformation is more significant than western part. The observed RATE is equal to a total movement of ~5km during 2.5-10 my which is consistent with geological studies carried out in this area.

Introduction: The 200 km long Gailatu-Siah Cheshmeh-Khoy (GSK) fault, with the same trend as the North Tabriz, Chaldiran, Nakhichevan and Pambak-Sevan-Syunik faults, is regarded as a part of the strike-SLIP fault system in the middle of Arabian and Eurasian collision zone, which extends from 42˚ E to 48˚ E with the Tutak and North-Tabriz faults in the west and east, respectively. This system includes a series of right-lateral strike-SLIP faults between the southern front of the Lesser Caucasus in the northeast and Bitlis-Zagros suture zone in the southwest. Tchalenko (1977), Apart and Iz (1977) and Baraka and Kadinsky-Cade (1988) was studied different segments of GSK fault and Berberian (1997) and Karakhanian et al. (1998, 2002 & 2004) describe them as a unified active strike-SLIP fault. Different sections of GSK fault was named by previous authors as the Northwestern Fault System (Tchalenko, 1977) and Balikgö lü fault (Baraka and Kadinsky-Cade, 1988), as well as, considering this fault as the western continuation of the North-Tabriz and Chaldiran faults by some authors has been called, North Tabriz-Gailatu fault system (Krakhanian et al., 1998) Balikghel-North-Tabriz fault (Karakhanian et al., 2002), Guilato– Siahcheshmeh– Khoy– Tabriz (Solaymani Azad et al., 2015) and Chaldiran-Khoy fault (Berberian, 1977). Seismicity: During historical times, some destructive earthquakes especially on the northwestern parts of GSK fault have been occurred. The disastrous M=7. 4 earthquake of 1840 A. D., reported as a strongest historical earthquake along GSK fault, destroyed the region along the NW part of this fault and more than 1000 people were killed in the towns of Maku, Dogubayazit, Avajigh (Kelissa-kandi) and many villages around NW part GSK fault (Ambraseys and Melville, 1982). About 72 km surface rupture along this and eruption of Ararat volcano is presumably was related to this event (Ambraseys and Melville, 1982; Karakhanian et al., 2002). After 3 years, an earthquake in 1843 A. D. devastate khoy city and killed between 500 and 1000 people (Berberian. 1977). Maku, Avajikh, Siahcheshmeh and its surrounding area, in 1968 A. D. damaged by Bedavli earthquake, considered to be related to activity of GSK fault (Berberian. 1977). Earthquakes of 363 A. D., 1319 A. D. (Qara Kelisa earthquake), 1808 A. D., 1834 A. D (Pambukh earthquake), 1900 A. D. and 1970 A. D. (khoy and Badalan earthquakes) are the other modeRATE historical and instrumental earthquakes of GSK fault (Ambraseys and Melville, 1982; Berberian. 1977). Outlines of this fault is very obvious and display a series of well-developed and preserved morphologic evidence indicating recent activity of the fault, same as, fault scarps and horizontal deflection in the Quaternary features, pull-apart basins, hot water springs and uplifted terrace deposits. The available literature, fault plane solutions, offsets of various geomorphological, man-made features and basaltic lavas indicate the right-lateral strike-SLIP nature of the GSK fault. Debate on the eastern and the northwestern terminations of the Chaldiran and North-Tabriz faults, respectively, have been raised in the few recent decades. In this paper, we investigated linkage of the North-Tabriz and Chaldiran faults, to the southeast and northwest of GSK fault, respectively. Methods and discussion: This paper also provides critical data for the Quaternary SLIP RATE and kinematic behavior of the GSK fault. One of the remarkable structural features is the Siah Cheshmeh pull-apart basin at a right step-over of the GSK fault. Two remarkable offsets along the strike of GSK fault define its horizontal SLIP RATE. To determine long-term SLIP RATEs, Copley and Jackson (2006) studied two morphological features that have been displaced along the GSK fault up to 13-km, SPAB and Agchay river. By using these displacements, they estimated an average horizontal SLIP RATE of 2-4 mmyr-1 since late Miocene along GSK fault. Along the SK, Quaternary basaltic lavas, known as Maku basalts, form a few ridges that are elongated parallel to the strike of the fault and displaced by ~ 725± 50. Using the about 400 kyr published age of these basalts (Pb206/U238 and Ar40/Ar39 dating methods, Allen et al., 2011; Lechmann et al., 2018), a mean SLIP RATE is 1/65 ± 0. 1 mmyr-1. On the SK segment, we excavated a trench to determine the fault geometry and its rake, and assessment of offsets which conditioned by the fault activity. In the trench, faults are shallow dipping with thrusting components that resemble foreberg structures in pressure ridges along strike-SLIP faults. Radiocarbon dating of the youngest deposits in the stream wall which displaced by 42± 4 m, yield 6764± 283 calBC, indicate the horizontal SLIP RATE of 4. 6± 0. 3 mmyr-1. Also, ourOur field observations have not identified any step along the SK segment, where more than four releasing and restraining bends have been reported by some authors along the GS segment. The existence of multiple bends along the GS segment relative to SK fault indicates lower geological offset of GS fault relative to SK fault, in accordance with theoretical consideration of Wesnousky (1988) for strike-SLIP faults. Based on this theory, the number of steps per unit length along the trace of strike-SLIP fault zones is a decreasing function of cumulative geological offset. In addition, published geodetic results show that the largest displacements occur along the North-Tabriz and Chaldiran faults, in the northwestern Iran and Eastern Turkey. Conclusion: Our results indicate that, SK segment of the GSK fault, due to its greater activity relative to its GS segment, can be considered as the western and eastern continuation of north Tabriz and Chaldiran faults, with a high SLIP RATE.

The evaluation of seismic potential along the Dehshir fault with 550-km length (accounting of northern and southern splays) is critical thanks to that more than 3.5 million people live in cities and towns located at vicinity of the fault. The Dehshir fault is considered as westernmost limit of N-striking dextral strike-SLIP faults set that slice Central and eastern Iran. Due to the lack of large recorded earthquakes (instrumental and historical) in Central Iran, access to seismic potential of active faults by studying the earthquake catalogs seems to be impossible. No instrumental earthquake has been recorded greater than mb 4.7 around the Dehshir fault and also historical data shows no evidence for occurrence of large earthquake around the fault. No sign of destruction in Marvast historical castle (at a distance of less than 10 km far from the Dehshir fault) built in Islamic period (~700-1250), shows any remarkable seismic activity until 750-1300 years ago. However, several evidence of geomorphologic markers such as drainages, gullies, streams and alluvial fans offsets, represent activity of the Dehshir fault in Late Quaternary. Geomorphic evidence at Marvast and Harabarjan sites record dextral - SLIP on the Dehshir fault during the Late Pleistocene-Holocene as major movement with minor dip - SLIP component. Rake of the fault movement has been considered for assessing to amount of horizontal and vertical SLIP RATE on the Dehshir fault. This value in the North Marvast site has been calculated ~10 degrees and according to right-bank offset on the Marvast river is  ~7 degrees with horizontal and vertical displacements of 13 m and 1.5 m, respectively. Combining cumulative offset markers with OSL dating implies the Dehshir fault in Late Pleistocene-Holocene time period SLIPs at horizontal and vertical components about 1±0.3 and 0.1 mm yr-1, respectively. We observed a minimum dextral offset along the Marvast segment in west of Harabarjan about 2 m that allows assuming the related magnitude and date of most recent large paleoearthquake on the Dehshir fault on the order of Mw 7 and 2000 years ago, respectively.

The Alborz mountain range accommodates some of the convergence between Central Iran and Eurasia. At present, the kinematics of the range involves a strain partitioning mechanism, and is associated with clockwise rotation of the South Caspian Basin. Left-lateral strike-SLIP faulting is present along the entire of its central part, while reverse faulting is affects its northern and southern borders. Several SLIP-RATE studies have been carried out along active faults in the internal and southern parts of the range. Our analysis provides new constraints on the activity of this important active thrust fault. We show that the fault generally is a hidden thrust fault, often associated with fault-bend and fault-propagation folds (forebergs). In the central part of the fault near Chamestan, radiocarbon dating on an old elevated terrace allows estimating the minimum vertical SLIP of 2. 0± 0. 5 mm/year. Considering a 34 degree slope for the fault, the minimum horizontal SLIP RATE will be 3 mm/yr and the minimum SLIP RATE along the fault plane will be up to 3. 6 mm/year. Our results confirm that the Khazar Fault is a major active structure in northern Iran, and represents a significant seismic hazard for the entire Central Alborz region.

Fault SLIP RATE distribution plays an important role in earthquake studies. Faults are loaded at very slow RATEs in continental interiors. So, interaction among faults and resulting SLIP distribution can give rise to earthquakes on other faults after a long period of quiescence and seismicity that can migRATE from one fault to the onother one.NW Iran-Eastern Turkey is a region of active deformation as a result of oblique collision of Arabia-Eurasia tectonic plates. In northwestof Iran, deformation between the Central Iranian block and the Caucasus domain is accommodated by a fault system and mainly by right lateral strike-SLIP on the North Tabriz fault. In the current study, we did SLIP RATE partitioning in the fault system of northwest Iranian plateau using the concepts of dislocation theory. Modelling approach is described by Gomberg and Ellis (1994), Flerit et al., (2003) and Armijo et al., (2004) and it differs from rigid block models (Reilinger et al., 2006; Djamour et al., 2011) in which dislocation conditions at the boundaries of blocks are often incompatible with geological evidences. In the alternative method of Flerit et al., (2003), SLIP everywhere has a direction of motion consistent with geological constraints. The dislocations do not divide the region into closed rigid blocks and SLIP can vary along strike as observed geologically. Finally we obtain a tectonic model for NW Iran-Eastern Turkey that is more realistic than rigid block model (Reilinger et al., 2006; Djamour et al., 2011) or models based on seismic or geologic strain RATEs (Haines, 1982; Haines and Holt, 1993; Jackson et al., 1995; Masson et al., 2005). For this purpose we use a three dimensional boundary elements method. First, we consider an elastic and homogeneous half-space for the study area. Then geometric data of fault system are collected from geological and geophysical sources including fault length, width, dip, and locking depth. For Lame coefficients, we use global average values. Both mentioned geometrical and physical data are kept fixed in the modeling process. Then, strain tensor that best fits the GPS data is estimated for the study area using least squares method. Then, stress RATE tensor is estimated using generalized Hook’s law. Geomerical chracteristics of faults, physical characteristics of crust and stress RATE tensor act as boundary conditions in the model.Faults are locked in normal direction but they are allowed to SLIP freely in strike and dip directions under the influence of boundary conditions. Regarding the strike changes of faults, the fault surfaces are divided by different segments in strike direction with constant strikes and dips. Then fault segment surfaces are divided into 1km elements. Finally, we have free SLIPping elements in strike and dip directions as inputs for modeling.Our model is fitted to the fault traces data set of NW Iran-eastern Turkey. The results indicate the dependency of the partitioned SLIP RATE on the boundary conditions and confirm the existence of interaction among faults. Also, partitioned SLIP RATEs show that the Chalderan, Guilato-Siahcheshmeh-Khoy, Nakhchivan, North Tabriz and Pambak-Sevan-Sunik faults are right-lateral strike SLIP in all cases. Also, the SLIP RATE in these faults is almost symmetric and reaches its maximum value around the center of the faults. We show that the maximum value of SLIP RATE in the fault plane is reduced by partitioning, which it will be definitely closer to reality. According to the gridding for SLIP RATE partitioning in the fault system, the highest value of SLIP RATE is always related to the North Tabriz Fault.Previous studies show that the geological SLIP RATE estimates are lower than the present-day GPS-derived SLIP-RATEs along the North Tabriz fault. We show that SLIP RATE partitioning solves this discrepancy by considering the mechanical interaction among faults. Our partitioned SLIP RATEs for North Tabriz Fault are lower than geodetic RATEs and are more consistent with geological RATEs. Finally, we present a model that fits best with the geological constraints.The proximity of the partitioned SLIP RATE to the paleo-seismic values indicates the closeness of the partitioning results to reality with the Boundary Elements Method, compared to other analytical and numerical methods. This research may open new research direction to handle the differene between geologic and geodetic SLIP RATEs values in the Iranian Plateau.The boundary elements method is both faster and more accuRATE for modeling compared to the finite element method used by Khodaverdian et al. (2015). Considering the effect of topography and sphericity of Earth, using the Galerkin boundary element method developed by Thompson (2019) is proposed to get more realistic results. The coefficients matrix in the of Boundary Elements Method is fully populated and in high dimensions it takes a lot of time to solve the resulting system of equations. Sparsing of the coefficient matrix using wavelet transforms is suggested (Ebrahimnejad et al., 2010) in this study. The use of iterative computational methods along with parallel processing will also reduce the computational time (Thompson and Meade, 2019).

For an idealized fault, SLIP distributions are symmetrical about a central SLIP maximum and follow an elliptical distribution in an elastic material. However, SLIP distributions in nature are neither symmetric nor elliptical. The distribution of SLIP along a fault depends on its geometry and that of neighboring structures, the remote boundary conditions and boundary conditions along the fault (s), and the constitutive behavior of the surrounding host rock (Bürgmann et al., 1994). In fact, an interaction among the mentioned parameters determines the manner of the SLIP distribution on the fault (s).On the other hand, fault SLIP distributions play an important role in earthquake studies.Because faults are loaded at very slow RATEs in continental interiors, interactions among them and the resulting SLIP distribution can give rise to earthquakes on other faults after a long period of quiescence and seismicity can migRATE from one fault to the other (Landgraf et al., 2009).The Alborz Mountains accommodate about one-third of the Arabian-Eurasian convergence (e.g., Priestley et al., 1994; Berberian and Yeats, 1999; Jackson et al., 2002).The Mosha-Fasham Fault, the Northern Tehran Thrust and the Taleghan Fault are active faults of the North of Tehran in Southern Central Alborz. It is necessary to analyze the seismic hazard in this area by considering the mechanical interaction among faults.In this research, a SLIP partitioning is done among the faults in the North of Tehran.First, an elastic and homogeneous half-space was considered for the study area. Then the geometric data of faults are gathered from geological and geophysical references including the fault length, width, dip, upper and lower locking depths. For Lame coefficients, we used average global values. Both mentioned geometrical and physical data were kept fixed in the modeling process.Then, a displacement gradient tensor that best fitted the study area is calculated using GPS data by least squares method. The strain-RATE tensor and finally stress RATE tensor were then estimated using the generalized Hook’s law. It is necessary to note that the orientation of the regional stress field (N36.5oE) was kept fixed in modeling for all of the study area. The stress RATE tensor acts as a boundary condition in the model. As another boundary condition, the faults were locked in a normal direction but they were allowed to SLIP freely in strike and dip directions under the influence of stress boundary conditions.Our problem involved a medium containing faults. Each fault had two surfaces or boundaries, one effectively coinciding with the other. A boundary element method called "the displacement discontinuity method" can cope with this problem. It is based on the analytical solution (Green function) to the problem of a constant discontinuity in a displacement over a finite line segment in a plane of a half-space elastic solid. Okada (1985) analytical solutions were used as Green functions for modeling.Regarding the strike and dip changes of the selected active faults, fault surfaces were divided into different segments in strike and dip directions with constant strike and dip. In this way, we had 22 fault segments in total. Then the fault segment surfaces were divided into 1×1 km elements. Finally, we had 8248 free SLIPping elements in strike and dip directions as input for modeling.In most cases, the results showed that the partitioned SLIPs did not have an elliptical shape. Also, they were not symmetric around a central maximum.The modeling results showed that most of the faults in the study area were left-lateral strike SLIP and reverse dip SLIP faults. Also, the left-lateral strike SLIP RATE magnitudes were often greater than the reverse dip SLIP ones. This was due to the obliquity of the horizontal along strike of the fault component of the principal stress was greater than the fault normal component.

Statement of Problem: Zirconia has been introduced as an appropriate structure for fabricating metal free copings. A major advantage of such restorations is esthetic concerns; however, due to its high strength, zirconia can also be used in posterior areas. One of the recent methods of making these restorations is CAD/CAM machines.Purpose: This study aimed to evaluate the fracture resistance of zirconia copings fabricated by two methods, CAD/CAM and SLIP casting.Materials and Method: 32 brass dies were fabricated for this study and divided into two groups of 16 dies each. Zirconia copings were made by CAD/CAM machine for one group and by SLIP casting method for the other. The copings were cemented to dies by a resin-modified glass ionomer (GC plus). A hardened steel ball with a diameter of 5 mm was used to apply the load to the copings in the long axis of the dies at a crosshead speed of 0.5 mm/min. Then the amount of force needed to fracture each coping was recorded. Independent Sample T-test was used to compare the two groups.Results: The average of fracture resistance for the CAD/CAM group was 1411±424 N and for the SLIP cast group it was 1542±412 N, having no significant difference (p>0.05).Conclusion: Zirconia copings made by CAD/CAM and SLIP casting methods have no significant difference in fracture resistance.