According to the standard No.2800, as well as most of the seismic hazard documents and analyses, Ahvaz city is reported as a region with moderate seismic hazard. These documents and information do not match with the fault condition of the region. In this paper, a "comprehensive study" of the seismicity of the Ahvaz region is presented in the field of deterministic and probabilistic seismic hazard analysis. Based on the results of this study, it seems that a fundamental review of the seismic hazard of Ahvaz is necessary. The earthquake risk analysis determines the maximum acceleration above g0.7 for an unspecified period of time and the possible risk analysis gives the maximum acceleration 0.16 g to 0.29 g for a planned earthquake and 0.33 g to 0.61g for a severe earthquake. In this way, it is suggested to include the city of Ahvaz among the cities with high seismic hazard to ensure the safety of the citizens. This study has opened a parenthesis in the field of earthquake risk in Ahvaz city and the "comprehensive study" statement is incomplete due to the lack of necessary geological information. In order to reach more reliable results and close this parenthesis in terms of financial issues, it is strongly recommended that in this field, more detailed geological and geophysical research focusing on detailed methods of paleoseismology with emphasis on accurate determination the specification of Ahvaz fault should be made.

The southwest province of Iran has a dry and semi-arid climate, with about 250, 000 hectares of sand dunes; therefore a comprehensive review and overview of these features and their correlation with other features is needed. In this study, over 200 sand samples were collected from the mobile and not mobile sand dunes to study the grain size of sand dunes in Khuzestan. The results showed there was no significant difference in the mean grain size from east to west, along a 200 km transect of the sampled area. The mean grain size in the west was 2. 87 to 2. 14 φ scale (136 to 226 microns) and in the east 3. 05 to 2. 16 φ (120 to 223 microns). The standard deviation of particle size of the samples was good and fairly good (0. 71 to 0. 35 φ ). Using tilt condensation particle diameter in the range of sand dunes area, folk scale (0. 1 to 1 φ ) was positive. These distances represent 20 to 50 km with mean transported distance of 35 km for the west and 50 to 200 km transported distance with mean value of 125 km for the east section of the Khuzestan province for the sand dunes. For the transport distances, average transport distance could be divided into four categories, including 3, 12. 5, 35 and 125 km. According to the results, the source of particles of the sand dunes in Khuzestan province is local, mainly from northwest and west.

Most of the megacities are located near the active faults. Ground motions in the vicinity of the active faults are associated with two main phenomena so called rupture directivity and fling effects. Therefore, it is important for earthquake resistance design and seismic hazard mitigation to evaluate the characteristics of near-fault ground motions in the megacities. In this paper, the near-fault ground motion was simulated using kinematic model for Tehran City, the capital of Iran. Tehran city was developed along the North Tehran Fault (NTF), which assumed to be the most probable seismic source for the city. Kinematic models are efficient tools to simulate long-period ground motions including slip heterogeneity (Asperities) on the fault and underground geology. Here, the near-fault ground motions are generated assuming NTF scenario using kinematic finite fault model. Then, the variations of faulting parameters such as rise time, maximum slip, rupture velocity, and site to fault distance on the near-fault pulse characteristics are numerically examined and discussed.

The area under investigation is the part of Fars (eastern Zagros) between Kazeron and Razak faults and investigation of its tectonic position is the main aim of this Paper. In order to this, results of previous workers have compiled together. In the other hand, geologic and seismic data have integrated with geophysical data and interpretations.Therefore, it appears that formation of high zones and embayments are the results of basement configuration and its magnetic anomalies are adapted on structural boundaries.Finally, according to all evidence, Razak, Nezam Abad, Sabzposhan and Kareh Bas faults are basement faults.

Torud fault is located in 110 Km away from the south of Damghan and trends ENE-WSW that is approximately E-W at its west end. In this termination region, observed structures indicate a special aspect of strike-slip fault terminations. These structures are of two sets: the first set are structures trending approximately N-S and are mainly compressional ones such as thrust faults and folds both verging to the east. These structures are in Paleozoic and Mesozoic rocks. Right lateral and normal shear structures, microfolds, foliations, and lineations are also associated with them. The second set is structures having NE-SW direction and include open gentle folds and younger thrusts which both verge to the south. They are mainly in Cenozoic and younger rocks but have made notable changes in older rocks too. Direction of Torud Mountain and its surrounding faults to direction of Arabia - Eurasia convergence, and effects of rotation and compression of Lut block and movements of its surrounding faults, led to transpressional deformation in the area under study The direction of slip in this system was related to tactors that were mentioned above and has been changed in response to the local changes of stress field. Strain in some locations has been partitioned into two components: shearing; and compression. They operated contempo-rarily or in two separate times. Other minor structures such as Reidel and P shears and folds of wrench tectonic also exist as they are predictable in shear zones.

the study area of this study is located in central iran and part of the Urmia-Dokhtar volcanic belt. It is the oldest rock in the region, depending on the median eocen. there are several earthquakes in this area caused numerous earthquakes. in general, an earthquake risk analysis study consists of several steps that will be addressed in this chapter. Two basic parts are important here. first, the recognition of tectonic Source that includes the recognition of seismic Source and knowledge of their main characteristics. these features can include length, distance, dip and dip direction, Siesmic potential, active faults, quaternary deposits. The second part deals with the seismic activity of the region. in this part, we identify and analyze the seismic status of the region as we identify prehistoric earthquakes (benefiting from the historical data of seismology). Such investigations resulted in the identification of valuable information, such as the Siesmic rate of Gutenberg-Richter coefficients, and seismic pattern. finally, the combination of these two parts in the form of a comprehensive model is modeled as the seismic model and can be considered as input data Research Method. Methodology: in this study, advanced EZ-Frisk software has been used for analyses. since in such studies it is necessary to apply at least a suitable Atteniuation relation. regard to features and geological conditions, tectonics and Siesmotectonic of this area in Iran, have finally used four new generations to calculate the seismic velocity parameters of the region by considering equal weight for each relationship. the probabilistic approach for determining the Siesmic parameters of this study is the probabilistic approach of risk analysis. in the PSHA method, using probabilistic models from Siesmic Source (point, line, path, or region), the maximum amount of seismicity values of the pick Ground Acceleration is calculated while using probabilistic models from Siesmic Sourse (point, line, path, or region). Analyses: Important faults of this area are Alborz, Kushke-e-Nosrat, Indes, qom – Zefreh, and Ipak. the Ipak fault over 100 km, along with east-west, is the most active element of Siesmotectonic in this range. The earthquake event of 1962 with magnitude 7. 2 has occurred as the largest instrument event in the region, relating to the activity of the Ipak fault. Alborz fault, 2 km distance, is the closest Siesmotectonic element to the Saveh city. this fault has overturned the from south east on quaternary deposit. according to the explanations that have been studied in the study section, the PSHA diagram for the Saveh city is calculated based on Fig. 3. therefore, the 0. 22 acceleration for Saveh city is evident in the period of 475 years. The most probable magnitude during the 475 year period is 5 / 5 and at a distance of approximately 21 km. the results clearly show that although Alborz fault is located near the middle of the Saveh city, it is not the main factor in the production of earthquakes for this city and produces only 8. 5 percent of total risk. Instead of the Kushk-e-Nosrat and Indes, respectively, at 18 and 21 km, respectively, have 90 % of the risk for the Saveh city. Conclusion: It was thought that the acceleration was the result of Alborz Fault that is almost from the middle of the Saveh city. therefore, the risk separation calculation was performed to determine the validity of this issue. but it was found that the main factor in the earthquake production was not for the city. After magnitude-distance deaggregation analysis, it is clear that the Indes fault with 21 km distance from Saveh city create the 45. 12% of hazard within its activity. In fact the controlling earthquake at 475 year return period is associated with Indes fault.

In this paper a monitoring GPS network has been designed for Bam fault in order to estimate the fault-model parameters, slip-rate and locking-depth, as accurately as possible. We integrated geological constraints to the optimization problem which limits the site locating. The optimization algorithm determines suitable places which are stable enough for setting GPS stations. The optimization tool is the genetic algorithm based on the principle of genetics as an intelligent method which gives the capacity of defining combined objective functions to optimize the geometry of the network for various applications. The numerical example shows that the fault-model must be considered in the fault monitoring network design.