iran

Part of the sun’s rays is made up of ultraviolet rays, which have short wavelengths and a lot of energy. Ultraviolet light in three ranges of long wavelength ultraviolet (UV-A) with a wavelength range of 0.390 - 0.315 μm, medium wavelength ultraviolet (UV-B) with a long range the wavelength is divided by 0.155 μm - 0.280 μm and short-wavelength ultraviolet (UV-C) with a wavelength less than 0.280 μm. UV-B light is the most harmful radiation on the skin and causes various side effects including sunburn, skin allergies and skin cancer. This radiation affects the DNA strand by altering the genetic material and increases the potential for intracellular carcinogenesis. Ultraviolet (UVI) index is a small (numerical) value that indicates the intensity of ultraviolet (UV) rays in the desired location and area. This index is a parameter for raising public awareness about the effects of UV radiation on health and how much skin protection is needed for different amounts. Based on the index provided by the World Health Organization, the concentration level or UV index is shown on a scale of 2 to +1. The higher the value of this index, the more destructive power it has on the skin and eyes.

In this study, the Level 3 product (OMUVBd-L3) of the solar ultraviolet (UV-B) index of the OMI sensor with a spatial resolution of 0.25 × 0.25 degree for the time series 2005 to 2020 was used. The required data was downloaded from the website http://aura.gsfc.nasa.gov in a daily time step and after the necessary processing; it was converted into monthly and seasonal values. The data used were converted into network data and information tables by applying the necessary algorithms, and the necessary outputs were extracted as a raster based on the geographical border of Iran. Finally, in order to better understand the temporal-spatial behavior of the UV index reaching the surface in Iran, the results were presented in the form of maps, graphs and graphs and the temporal-spatial estimation of solar UV radiation in Iran.

Spatially, there is a significant difference in the distribution of UV-B input radiation in Iran. According to the global index of solar ultraviolet radiation, more than 90% of Iran's area is exposed to high to very high radiation risk. The highest average of UV-B index is related to the summer season (11.29) and the lowest average is related to the winter season (3.53). In terms of spatial distribution, there are significant differences between the seasons. The spatial distribution of the monthly UV index provides more information about the details of changes in solar UV radiation reaching the earth's surface throughout the year; So that it is possible to determine the minimum and maximum, months as well as the months with balanced UV radiation conditions. A comparison of the amount of UV-B radiation in different months clearly shows January as the least dangerous month and June as the most dangerous month of the year. Since the value of the solar UV index is a function of the total amount of incoming solar radiation. Therefore, factors such as the angle of radiation, the duration of radiation and the amount of UV control the UV-B solar ultraviolet index.

The results of the analysis and comparison of seasonal and monthly maps of solar UV index in Iran, indicate that in all months and seasons of the year from north to south, the intensity of solar UV radiation increases. In the northern part of Iran, due to higher latitude and less solar radiation reaching the earth's surface, the UV-B index is lower than other parts of Iran. On the other hand, in the more southern offerings, because both the angle of radiation is vertical and the sky is clearer, it provides the conditions for receiving the maximum amount of solar energy and consequently UV-B solar ultraviolet radiation. The prevalence of such conditions is established in all months and seasons of the year, so that the radiant regions (ultraviolet UV-B) are fully compliant with the mentioned conditions. Therefore, it can be said that in the warm period of the year (spring and summer), the highlands as well as the lower offerings have more solar UV radiation and therefore the risk of eye and skin vulnerability increases. Therefore, it is recommended to take protective measures against UV radiation if it is necessary to be present in areas exposed to direct sunlight.

 Mineral chemistry data as well as petrography provide a comprehensive picture of magma crystallization conditions that support the conclusions based on geochemical data. In addition, the chemical composition of minerals such as clinopyroxene, olivine, biotite, feldspar, and Fe-Ti oxides reflect physicochemical parameters (pressure, temperature, and oxygen fugacity), crystal growth history, and melt origin. The pressure, temperature and oxygen fugacity parameters are estimated from chemical data of various rock-forming minerals to provide information regarding the crystallization of magmas. The essential purposes of present study are to determine the physicochemical conditions (temperature and pressure), to identify the tectonic environment and to propose an emplacement model for Pargeh mafic magmas formation.

Regional Geology:

The Pargeh area is a part of the Central Alborz Magmatic Belt (AMB) (Figure 1). There are extensive magmatic sections in this zone including the Cenozoic calc-alkaline and alkaline (potassic) magmatism generated in an arc and back-arc setting in an extensional environment (post collision). This belt is mainly composed of Upper Precambrian to Eocene sedimentary and volcanic sequences intruded by Mesozoic to Cenozoic plutons, in the central and western parts of the belt. The igneous rocks of the north and northeast of Qazvin were formed during three volcanic phases, of which only two phases can be seen in the study area. These Late Eocene-Oligo-Miocene plutonic rocks are related to post-collisional magmatic activities originated in back-arc extensional basins and have calc-alkaline to high-potassium shoshonitic characteristics. According to U–Pb dating, the age of the syenite and monzonite rocks is Late Eocene. But the exact age of the Pargeh gabbroic rocks is not known, considering that these intrusions were injected into Eocene tuffs, they are Late Eocene and possibly Oligocene.

The main minerals were analyzed by an electron microprobe at the Queen’s Facility for Isotope Research (QFIR), Queens University, Kingston, Canada. Operating conditions were as follows: the acceleration voltage was 15 kV, the beam current was 20 nA, and the diameter of the probe was 3 µm (Tables 1 to 6).

Petrography:

Field and petrographic observation show that most of the Pargeh pluton is monzogabbro and olivine gabbros make up only a small part of the pluton. Olivine gabbro is a medium- to coarse-grained mesocratic-melanocratic rock. Olivine gabbro and monzogabbro are texturally varied. In both samples, intergranular, poikilitic, sub-ophitic and granular textures were identified. Olivine gabbro are dominated by olivine (20-25%vol), clinopyroxene (15-20 %vol), plagioclase (50-55 %vol), biotite (~ 5 %vol) and K-feldspar (~ 5 %vol). Accessory minerals include apatite and Fe-Ti oxides. Monzogabbros are characterized by a high proportion of plagioclase (55-60 %vol) and clinopyroxene (20-25 %vol), biotite (5-10%vol) and K-feldspar (8-10%vol).. Fe-Ti oxides and apatite are common accessory minerals in monzogabbros.

Based on research on the distribution of Ti in silicates and oxides of magmatic rocks, Verhoogen (1962) proposed that the crystallization temperature of clinopyroxene is positively correlated with its Ti content. Therefore, the higher clinopyroxene, crystallization temperature, the more Ti clinopyroxene likely to contain. The TiO2 content of clinopyroxenes in olivine gabbros is slightly higher than that of monzogabbros, pointing to the clinopyroxenes in olivine gabbro having a relatively higher crystallization temperature compared to that of clinopyroxenes in monzogabbro. In the 9-A and B diagram, all the samples are in the range of alkaline basalt, so the parental magma can be an alkaline magma. As mentioned above, clinopyroxenes have high amounts of Al and Ti, consistent with the evolution of an alkaline magma. High amounts of calcium in the studied clinopyroxenes indicate that the parental magma may have an alkaline nature. This tectonic setting discrimination diagram can distinguish basaltic clinopyroxenes from volcanic arc basalt (VAB), ocean floor basalt (OFB), intraplate tholeiite (WPT) and intraplate alkaline environments (WPA). In the F1-F2 tectonic environment discrimination diagram, all the study samples fall within the range of volcanic arc basalts (VAB+OFB), which shows that these rocks are probably formed in a volcanic arc and arc-related tectonic setting environment. In general, all tectonic discrimination diagrams based on clinopyroxene chemistry indicate an arc-related environment for the parental magma.

The mafic rocks of Pargeh are composed of olivine gabbro and monzogabbro which are characterized by the presence of olivine, plagioclase, clinopyroxene, biotite and K-feldspar. The mineral chemistry results show the role of fractional crystallization as the main process in the formation of the parental magma of the rocks under study The chemical features of clinopyroxenes point that the parental magma must belong to a silica under-saturated alkaline series, characterized by high temperature, low pressure, low Si and high Ca contents possibly formed in a volcanic arc tectonic setting environment. As the xamined thermobarometers data show, the olivine gabbros generated at higher temperature and pressure than that of monzogabbros indicating that the olivine gabbros probably crystallized at a greater depth.

Temperature is a major variable in the Earth's climate system, which plays an important role in energy exchange interactions between the Earth's surface and the atmosphere. There are various sources for temperature estimation, including ground stations, satellite products, reanalysis datasets, and multi-source weighted-ensemble datasets. Reanalysis datasets are generated by combining different types of observational data for a certain time in numerical weather prediction models and using ground and satellite observations. The purpose of this research is to investigate the performance of the ERA5-Land and AgERA5 reanalysis datasets as well as the MSWX multi-source dataset to determine reliable datasets for estimating temperature in Iran. First, we evaluated the temporal variations of the three datasets against the station data. We used the air temperature from 98 stations for 30 years from 1991 to 2020. Three metrics including Root Mean Square Error, Bias, and Index of agreement were used to evaluate ERA5-Land, AgERA5, and MSWX datasets.Then, considering the seven main climate zones of Iran, the spatiotemporal quality of the annual mean temperature was evaluated in different climate zones. The results showed that all three datasets have less error and bias in the estimation of the minimum temperature of Iran. However, AgERA5 and MSWX significantly showed less error in the estimation of the maximum temperature with RMSE of 1.74℃ and 1.42℃, respectively. On the other hand, the ERA5-Land dataset shows overestimation (5.05℃) and high error values (5.07℃) over the country-averaged. The results showed that the MSWX dataset has a better performance in estimating Iran's temperature with an average bias of 1℃. The interannual variations and decreasing and increasing trends of temperature in three datasets with correlation above 0.86 in all climate zones of Iran show a high consistency with observational data.The RMSE in all three datasets reaches its maximum in the winter season in mountainous climate zones of the country. This may be caused by snow-albedo feedback in mountainous climate zones. The findings showed that performing bias correction and downscaling methods as they have been done in MSWX and AgERA5, significantly improved the reanalysis dataset compared to the direct model output. Nevertheless, in the southwest of the Caspian Sea, the bias-corrected MSWX and AgERA5 show more errors than ERA5-Land. In general, the values of bias and RMSE in all three datasets are affected by the physical schemes of the model, parameterization, and data assimilation system, or the downscaling and bias correction methods. However, sources of bias can be different in different seasons of the year. The monthly spatial distribution of temperature in Iran shows that the minimum temperatures are located in the middle of Alborz and the northwest mountains of the country, and the coldest month of the year is January with a temperature of -10.8℃. The maximum temperatures in Iran are located in the southwest of the country and the southern coasts, and the hottest month of the year is July with an average temperature of 42.38℃.

Complex network theory has appeared as a suitable tool for studying complex phenomena. Earthquakes show spatio-temporal complex behavior that can be studied using complex networks, which enables us to recognize the global properties of Earthquakes. It is so hard to consider all factors affecting the movement of faults and put them into a compact mathematical equation in order to describe the earthquake phenomenon. In complex network theory, we do not need to know details of the fault system. Using the network method, knowing  the magnitude, time of occurrence and location of seismic events, we are able to understand several aspects of the earthquake phenomenon.  Studies on earthquakes using the network method are based on how the network is constructed. It was tried to show that the main statistical features of earthquake phenomena in any region can be retrieved from the associated earthquake network.  In this research, the Baiesi-Paczuski (2004) network model used to investigate the earthquake network. Earthquake epicenters play the role of network nodes and the relationship between both nodes was established by the relationship defined by Baiesi-Paczuski. In this project, by constructing the network, the parameters of seismicity (a-value, b-value), fractal dimension and correlation ratio in the Iran region. In the first attempt we drew out the Gutenberg–Richter law from the earthquakes network and the Omori law from the Baiesi-Paczuski network model.  We have used data recorded from 1996 to 2020 data at all the broadband and short-period stations of the Iranian Seismological Center. The results showed that b-value≈ 0.93 and a-value≈6.9  and. Also, the results showed that for df≈1.56  each earthquake with a certain magnitude, the aftershock rates follow the Omori law with the line gradient of p≈-1 and the earthquake degree distribution function in Iran from the power relationship ((P(k)~kγ) with a γ = 1.59. In addition, the distribution function showed that the correlation relation is also a power relationship.

Cut-off  lows are cold -core cyclones in the upper troposphere that are identified as local minimums of geopotential elevation fields in the range of 500 and 200 hPa )Nito et al, 2008; Pinheiro et al, 2017; Muñoz et al, 2020(. Cut-off lows occur in most seasons, often in late winter and early spring. One of the synoptic patterns affecting temperature and precipitation as well as heavy rainfall in Iran is cut-off lows. This study has been compiled according to the importance and relationship between cut-off lows and heavy rainfall in the statistical period of 33 years (1986-2018). In this study, the climatology of cut-off lows systems at the level of 500 hPa of the northern hemisphere effective on heavy rainfall in Iran has been discussed. The ECMWF reanalysis data were used to identify and track cut-off lows that lasted for more than 48 hours in the statistical period of 33 years (1986-2018). For this purpose, geopotential, wind, and temperature data also were used.

In this study, from the average daily data: Geopotential height, wind orbit, and temperature level of 500 hPa of the re-analyzed ECMWF European site with a grid step of 0.125 * 0.125 in the statistical period of 33 years (1986-2018) Used in areas including 0 to 80 degrees north latitude and 0 to 80 degrees east longitude. The Tibaldi-Multney index was used to identify Cut-Off low. And the Cut-Off lows that were effective in Iran's heavy rainfall were studied.

Annual, monthly and seasonal distribution of cut-off lows during the statistical periodIn the statistical period of 33 years (1986-2018), a total of 632 cut-off lows with a lifespan of 2 days and more were identified. The average was 18.87 days for each year. The trend line or regression during the statistical period shows that the amount of cut-off lows is increasing.The share of cut-off lows in heavy rainfall in the four regions of Iran In the northwestern region of Iran, the highest percentage of the effect of shear compressions on heavy rainfall is in Kashan, Takab, Mahabad, Maragheh, and Tabriz stations, respectively. The lowest percentage of the impact of this phenomenon on heavy rainfall was inKhorramabad, Karaj, Babolsar, and Parsabad stations, respectively. In the southeast region, the highest percentage in Chabahar, Bandar Abbas, and Sirjan stations and the lowest percentage were in Jask, Zabol, and Khash stations. In the southwestern region, the highest effect is in Bushehr and Kish stations and the least effect is in Omidieh and Masjed Soleiman stations. In the Northeast, the highest share was in Birjand, Ferdows, and Tabas stations and the lowest impact was in Gorgan, Mashhad, Quchan, and Bojnourd stations.The amount of heavy rainfall and the effect of cut-off lows in it in different regions and Iran The highest occurrence of heavy rainfall due to cut-off lows was in the northwest region with (36.62 occurrences) and the lowest in the southeast region with (8.5 occurrences). In research study stations (76 stations), the frequency of heavy rainfall during the study period was average (124.76 events) and the effect of shear cut-off lows on heavy rainfall in total (26.1 events) in the station has been.

A total of 632 cut-off lows with a lifespan of 2 days or more were identified in the research area. The trend line of the statistical period has a slight positive and increasing slope; the most occurrences of cut-off lows is in October, March, and January. The lowest incidence of cut-off lows is in July, August, and June. Seasonally, the highest number of cut-off low events was in spring, winter, and autumn. The highest occurrence of heavy rainfall under the influence cut-off lows was in the northwest region and the lowest in the southeast region during the study period. Therefore, it can be concluded that the entry of cut-off lows from the northwest and the proximity of the northwest region to the formation location of cut-off lows may be a factor contributing to the highest frequency of heavy precipitation events influenced by cut-off lows. Furthermore, the distance of the southeast region from cut-off lows indicates a lesser impact of this phenomenon on heavy precipitation in this area.

Gneissic domes are evidence of vertical movements in both compressional and extensional tectonic regimes in orogenic systems. These domes are evidence of mutual interaction between gravitational and tectonic forces in the continental crust. Gneissic domes have unique structures in deformed regions. These domes include a complex of deformed metamorphic rocks and intrusive masses covered with the upper layers of the crust. The Toutak gneissic dome is located in the high-pressure-low-temperature Sanandaj-Sirjan metamorphic belt and is an example of gneissic domes in the Zagros orogenic system. The purpose of this research is to determine the deformation temperature based on the petrofabric characteristics of quartz minerals in the mylonite rocks exposed in the Toutak gneissic dome. The temperature obtained from the quartz c-axis pattern shows the temperature range from 260±50 to 565±50 °C for the deformation. The asymmetry of quartz c-axis patterns indicates the occurrence of dextral shear during the deformation.

It is challenging to estimate how the climate of a region will change under global warming in the future. Among the essential climate variables, temperature, relative humidity and wind speed are very important, and their changes in relation to each other can have many consequences, such as increasing heat stress and evapotranspiration.    In this research, we investigated future temperature, wind speed, and relative humidity in Iran. Five models, namely GFDL-ESM4, IPSL-CM6A-LR, MPI-ESM1-2-HR, MRI-ESM2-0, and UKESM1-0-LL from the Coupled Model Intercomparison Project Phase 6 (CMIP6) have been evaluated versus observations for 1990-2014. A multi-model ensemble was generated with the Integrated Weighted Mean (IWM) method from selected CMIP6 models, and the performances of individual CMIP6 and CMIP6-MME models in estimating temperature, wind speed, and relative humidity were investigated. The results showed that all five selected models are capable to reproduce the variables; however, the CMIP6-MME significantly improved the results. The CMIP6-MME showed good agreement with observational data both in terms of climatology and spatial distribution of each variable, and its performance is higher compared to individual models.   We have used two Shared Socioeconomic Pathways (SSPs), namely SSP2-4.5 and SSP5-8.5, and three-time periods, namely near-term (2026-2050), midterm (2051-2075), and long-term (2076-2100) relative to the historical period (1990-2014).The results of this study showed that Iran will undergo changes in temperature, wind speed, and relative humidity spatial distribution in the future. The decrease in relative humidity and dryness of the air in the future can have important consequences for agriculture, food security, and water resources management. The findings of this study, in agreement with previous studies, emphasize the significant increase in temperature throughout Iran. Under the SSP2-4.5 (SSP5-8.5) scenario, the average annual temperature of the country increases by 1.40 (1.83), 2.34 (3.58), and 2.99 (5.58) degrees Celsius in the near (2026-2050), middle (2051-2075), and far (2076-2100) future, respectively.    Along with the increasing trend of temperature in Iran, wind speed will decrease in most regions of the country in the middle and end of the 21st century under two SSP scenarios. This decreasing trend can be a result of decreasing atmospheric instability and increasing potential temperature. The northwest of Iran has shown the maximum increasing temperature and the maximum decreasing wind speed. The decrease in relative humidity in Iran has been evident since the 1990s, and the projection results indicate that it will decrease in large parts of Iran in the future. However, the relative humidity in the southeast of Iran shows an increasing rate in the future. Results of this study show that the heat stress will be significantly higher through SSP5-8.5 than SSP2-4.5 in the 21st century due to the decrease in wind speed and increase in temperature throughout Iran. Therefore, Iran should quickly move on to formulate and implement long-term adaptation plans for resilience against climate change.

Masteroon area is located in the northeast of Azna city, in the Sanandaj-Sirjan zone. The rocks units include a relatively uniform sequence of slate and phyllite with a granodiorite intrusive mass that includes pegmatitic complex. The most important minerals include quartz, alkaline feldspar, plagioclase, tourmaline and muscovite. Quartz is high pure and does not have any other elements. EPMA shows the albite-type feldspar with a lesser extent than orthose-type with a less than 550⁰C crystallization temperature. This can be due to the result of below the freezing of the feldspars composition during the cooling of the mass. The available tourmalines are of schorl and alkaline type with a deficiency in the X position, and their numerous and abundant presence, automorphism and absence of chemical zoning, indicate that tourmalines are magmatic. Muscovites are present in two forms: coarse-grained in pegmatites and fine-grained in joints and cracks, and the coarse-grains does not stretch to phengite.

The Pargeh pluton is located in the northeast of Qazvin. The rocks of this pluton mainly include monzogabbro and olivine gabbro, which mineralogically contain olivine, clinopyroxene, plagioclase, biotite and alkali feldspar. Geochemically, they have features of potassic alkaline magmas with enrichment in large ion lithophile elements (LILE: Ba, U, Pb, Sr) and depletion in high field strength elements (HFSE: Nb, Ti, Zr), which are similar to subduction zone magmatism and mantle-derived magmas. Chondrite-normalized REE plots show enrichment in light REE (LREE) (4.43< (La/Yb) N <8.58)) and slight negative anomalies (Eu/Eu* = 0.82-0.99). The studied gabbroic rocks have resulted from fractional crystallization of a parental magma which formed by partial melting of depleted lithospheric mantle with spinel-peridotite composition. The primary ratios of 87Sr/86Sr and 143Nd/144Nd (0.70493-0.70525 and 0.51272-0.51269) are compatible with the parental magma formation in the mantle wedge. The values of ɛNd(i) (1.47 to 1.92) are in the range of mantle-derived melts. We suggest that Pargeh gabbroic rocks are part of the Alborz magmatic belt, which according to the geochemical data, their tectonic setting is consistent with a post-collisional, back-arc extensional environment.

In the context of global warming and climate change, carbon dioxide (CO2) is known as one of the most important greenhouse gases that has significant effects on the global warming. It is considered as one of the consequences of the accumulation of greenhouse gases. It is very important to control the amount of CO2 emissions and reduce the effects of human activity on climate warming and understanding the spatial and temporal distribution of atmospheric CO2. Due to the coarse horizontal resolution of global transport models, simulation of CO2 concentration in hourly/weekly time intervals and with a good vertical resolution in continental or coastal sites is one of the most important environmental challenges especially in the Middle East.   While compiling information on CO2 emission from different sources, regional numerical simulation with spatial resolution of 30 and 10 km of atmospheric CO2 concentration was carried out using the Weather Research and Forecasting-Chemistry (WRF-GHG) model. XCO2 information retrieved from GOSAT satellite observations was used as accuracy control information and evaluation of simulated results in CO2 column concentration in hot (August) and cold (February) seasons compared to the output results of TM3 global model.  The performance of simulations in predicting the concentration of greenhouse gas carbon dioxide (CO2) for the study period of February and August in 2010 showed that the spatial and temporal variability of meteorological variables have been simulated well with the correlation coefficients of 86-92%, 75-67% and 76-82% for temperature, wind and relative humidity, respectively. The evaluation results showed that the WRF-GHG model performs better than the TM3 global model in terms of statistical errors. On average, the skewness error values in both hot and cold seasons are -0.79 and 0.45 (-0.85 and 1.12) in the regional (global) model, respectively. The evaluation results showed that the difference between the simulated concentrations and XCO2 observations from the GOSAT satellite could be caused by the underestimation of emissions produced by human activities, oceanic emissions, and exploitation of fossil fuels. This study showed that the WRF-GHG model is able to simulate well many important features of the atmospheric variables fields in Southwest Asia (Middle East-Iran region); then its application for future studies in this region is assured.

Earthquake descriptions documented in various reports are one of the most important datasets to assess the macroseismic intensity distribution of an earthquake and preparing different intensity maps. This information consists of building damages and earthquake environmental effects as macroseismic data points (MDPs). Extracting the macroseismic parameters of the earthquake will be possible using these MDPs. Each location with any information can be considered as a point of the intensity map.    In this study, Ardekul Ghaen earthquake (10 May 1997) was selected to show the effect of using complete dataset to assess the intensity values and prepare the earthquake intensity map. There are several reports for this earthquake. Researchers in different fields in their reports mentioned to various descriptions of this earthquake effects consisting of descriptions on different types of building damages, descriptions on various environmental effects, and information from people who felt the earthquake. For this study, the descriptions published in different reports were collected separately for the cities and the rural areas (MDPs) affected by the earthquake. Totally, about more than 100 locations with various effects from the earthquake were reported for this earthquake. Since the descriptions of all reports were not complete, the intensity values were assessed using all descriptions reported by different references for each MDPs. As the main dataset of this study is MDPs with their intensity values, complete descriptions of each MDP reported by different references were considered for reassessing the intensity values of MDPs. However, the intensity maps were separately prepared for each selected report using their reported MDPs. On the other hands, depending on the reported MDPs, the intensity maps of each report will be different from others. For this study, to show that the effect of completeness of the earthquake reports on estimating the results depends on their datasets, five reports were selected from different reports published. The intensity maps of this earthquake were separately plotted based on each of the selected reports. According to this study, the best report should be the one with more complete information of each MDP affected by the earthquake. It consists of all descriptions related to the building damages or the environmental effects. Thereafter, the earthquake intensity values can be assessed with more accuracy. Moreover, the intensity map of the selected earthquake will also be plotted with more details. If there are enough MDPs, the macroseismic parameters of the earthquake can be also estimated. More MDPs and complete description for each one, more accuracy and high quality estimations.

In this research, we investigate the seismic hazard associated with the Kheyrabad blind thrust fault at the north of Birjand, Eastern Iran. Field measurements from a structural transect through the Kheyrabad anticline indicate fault-propagation folding above a 38° northeastward-dipping blind thrust fault which probably reaches into a horizontal detachment at a depth of ~500 meters. In this research, in order to evaluate the seismic risk of Khayrabad blind fault have been investigated, parameters such as average slip rate, maximum earthquake (Mmax) and its recurrence. Obtaining estimates of the slip-rate on the blind fault, and of the rate of crustal shortening are difficult, but we assume that transport of material on the horizontal decollement at depth is balanced by extrusion of material at the surface, we can produce approximate measurements of slip-rate and shortening by using area balancing. In this method, the rates of fault slip, horizontal shortening, and uplift have been estimated as 0.75, 0.59, and 0.46 mm/yr, respectively. Using the regression equation between earthquake magnitude and rupture area, magnitude of the maximum earthquake is estimated at 4.7. Also, using the empirical relationships between magnitude, coseismic displacement and slip rate, the recurrence of this earthquake is predicted to be 577 years. According to the obtained slip rate (0.75 mm/yr), the activity grade of Khairabad blind fault is considered moderate.