مجله پژوهش های دانش زمین
پیاپی 56 (زمستان 1402)

Temperature is a key atmospheric variable and has a direct effect on other atmospheric variables including precipitation. The average global temperature has increased in recent decades, which causes an increase in evapotranspiration, an increase in climate extremes, drought, and wildfires. Examining the performance of different versions of ERA5 can help in choosing the best version of ERA5 in climate studies of the country. This research examines Iran's temperature based on deterministic and probabilistic versions of the ECMWF-ERA5 reanalysis, which replaces the previous releases.

The data used in this study is the average monthly air temperature which we examined in two ERA5 deterministic and probabilistic datasets. To investigate the impact of horizontal resolution on temperature estimation, two horizontal resolutions of 0.25o and 0.5o from the deterministic and probabilistic versions of ERA5 have been used. Also, the multi-member Ensemble of Data Assimilations (EDA) version with a horizontal resolution of 0.5o has been used to compare ERA5 probabilistic dataset versus its deterministic version. Before evaluating the data of three different versions of ERA5, a multi-member ensemble dataset was generated from 10 different members of the probabilistic version of ERA5, which are presented as Member0 to Member9.

The results showed that ERA5 correctly estimates the spatial distribution of average temperature in Iran. However, in Iran's higher latitudes and regions with complex topography, the performance of ERA5 in temperature estimation is worse than in arid and semi-arid interior regions. In addition to the complex topography, the ERA5 performance is affected by certain complex geographical features such as the southern coast of the Caspian Sea. The worse performance of ERA5 temperature in the coastal areas of the north of the country and Zagros may reflect some shortcomings in the accurate representation of the geographical features of these areas, such as the air-sea interaction and the simultaneous interaction of local moist currents with the coastline and the complex topography of Alborz and Zagros.

Comparing different versions of ERA5 with observational data showed that the deterministic version of ERA5 with a resolution of 0.5o systematically underestimates the temperature in Iran, which is -7.41% for the area-averaged of the country. On the other hand, the deterministic version with a resolution of 0.5o overestimates the temperature of Iran by 12.01% in the area-averaged of the country.Examining three different versions of the ERA5 dataset for two deterministic and probabilistic versions showed that the deterministic version of ERA5 with a horizontal resolution of 0.25o with an area-averaged bias of 1.07 oC and a percentage of bias of 9.36% shows the best estimate of Iran's temperature. The monthly distribution of Iran's average temperature based on the ERA5 deterministic version with a resolution of 0.25o showed that the minimum temperature of Iran is -10.49 oC in January and the maximum temperature is 39.83 oC in July. The temperature in all months and the annual average follow the topography in Iran. The minimum temperature is negative in 5 months of the year (January, February, March, November, and December) in Iran.

Rivers are crucial for the society because they provide fresh water for agriculture, human needs, industry and transportation. Therefore, water quality assessment has been considered as an important issue by many researchers in the field of hydrology and hydrogeology. Water quality is influenced by natural and anthropogenic effects including local climate, geology, irrigation practices and the use of water resources.

Cheshmeh Kileh catchment is one of the most important basins in the west of Mazandaran province and has two main tributaries, Dohezar and Sehezar, which, after surveying mountainous areas, join in a plain area and form the Cheshmeh Kileh river. This catchment originates from Nosha Heights, northern heights of Alamut and Alam Kooh Glacier. According to the Meteorological Organization report, it has a humid climate with hot summers and slightly cold winters. . The center of gravity and grading of the canals were determined using a Digital Elevation Model (DEM). Sampling points were determined based on the degree of waterway and possible terrestrial and anthropogenic pollutants. After sampling, the samples were sent to the laboratory to determine the concentration of the main anions and cations, Acidity, TDS, Conductivity and Alkalinity. To study the hydrogeochemical changes in the catchment area, Piper, Durov, Stiff, Schoeller and radial Plot diagrams were drawn in AqQA software and Gibbs diagram and role index diagram were drawn in Excel. Then the process of hydrochemical evolution, type and hydrochemical facies of water were determined and the hydrogeochemical control mechanism was investigated.

The two sub-basins of rivers Dohezar and Sehezar have different chemical compositions of water at the source, which are influenced by the lithology of the region in their path, and finally, by joining together, the water type has evolved as bicarbonate-calcium. In the meantime, the sample that originates from the landfill effluent (CH16) also flows into this river, but due to the high volume of water flowing in the river, it does not have a significant effect on the overall water quality downstream. According to the Gibbs diagram, the main factor controlling water chemistry in the Cheshmeh Kileh catchment is the chemical weathering of the minerals that make up the rocks, and only in the CH16 sample (landfill) was the anthropogenic factor effective. Also, with the help of the roll index, it was found that saline seawater or trapped fossil saline water did not affect the composition of ions in the surface water of this catchment. With the help of the models provided for the Stiff diagram by Hounslow, the origin of water in CH1 sample was determined from gypsum lithology and other samples were mostly from limestone lithology. The presence of gypsum interlayers in the structure of Karaj Formation upstream of CH1 station in Maran village can be a proof of this analysis. Based on the relationship between origin and water composition, the origin of some stations was identified from the dissolution of evaporative rocks and others due to dewatering of silicates.

In general, it can be concluded that the chemical composition of water in Cheshmeh Kileh catchment has been affected by dissolution and oxidation of calcites and sulfides, as well as oxidation and weathering of silicates and sulfides.

Landslide is defined as the movement of a mass of rock, debris, or earth down a slope. Sedimentary mass movement can be various factors that play an important role in the destruction of communication roads and residential houses, the destruction of pastures and gardens, as well as erosion and sediment transport in the basins. Various studies have been conducted on landslide risk zoning using logistic regression model. Which factors such as distance from fault, slope, slope direction, land use, rainfall, lithology, elevation and distance from river and road were reported as the most important factors affecting landslides.

In this study, Chaharmahal and Bakhtiari province as an important mountainous region in the country was studied. Reviewing past research showed that among the various factors affecting landslides, 9 factors including distance from fault, slope, slope direction, land use, precipitation, lithology, elevation classes and distance from river and road as independent variables, are the most important factors. To analyze the data, first 200 landslide areas were randomly selected, and another 200 points in the whole area without landslides were also randomly selected. After preparing the layers, the logistic regression model was performed to investigate the role and weight of each of the 9 independent variables. The accuracy of the model results was checked using three statistics, R2 Naglerk, R2 Cox and Snell and factor-2LL.

The results of running the logistic regression model, showed that among the studied variables, the texture and slope of the land, respectively, can be considered as the most effective factors in creating landslides in the region. After that, the distance from roads and finally the amount of rainfall has the greatest impact on landslides in the studied region. The evaluation results of the model obtained from these five parameters, showed that the overall accuracy of the model is 90.9% and acceptable. After that, the distance from the roads is an effective factor in creating this phenomenon, and in the end, the amount of rainfall is effective on the landslides. The results of evaluating the correctness of the logistic regression model show that the factor -2LL in the last iteration of the model is equal to 117.893 and the coefficients of R2 Naglerk, R2 Cox and Snell are 0.65 and 0.42, respectively, which indicate the accuracy of the model. Based on the obtained results, a landslide risk zoning map was prepared for the study area.

Due to the high number of landslides recorded in Chaharmahal and Bakhtiari province and the risk of new landslides, this study was conducted on the area to determine the factors that have the greatest impact on this phenomenon and areas with a high risk of landslides. Based on the results, it can be stated that in addition to natural factors (land type, land slope and rainfall), some human factors, including unprincipled road construction, have an important role in landslides. These factors have caused 13.8% of Chaharmahal and Bakhtiari province is at high risk of landslides. To reduce the risks, ecosystem change and land use of the regions should be avoided as much as possible.

Regional sustainable development is influenced by many variables, and institutional capacity is one of them. If institutions have significant capacity, development is more possible, that's why this subject has a special importance for study. However, there are fundamental challenges in using the institutional capacities, which, especially in developing countries, have endangered the goals of sustainable development more than before and should be discussed and investigated.

This research aims to answer two questions with a comparative study of Bojnord and Raz and Jorglan in North Khorasan province. 1- What is the level of institutional capacity in the study areas? 2- What is the relationship between institutional capacity and regional sustainable development? The statistical population of the research is at the level of institutional employees and civil society, from which 400 samples have been selected from each of them.

The results of the research based on the independent one-sample t-test show that according to the employees, the average of the institutional capacity components in Bojnord is equal to 2.63 and in Raz and Jorglan it is 2.44, which is lower than the average. According to the opinions of the civil society, institutional measures in line with the sustainable development of the region are 2/44 in Bojnord and 2/37 in Raz and Jorglan, which can confirm the obtained results with a 95% confidence level and realize the unfavorable performance of the institutions. Also, the results of Pearson's test show a positive and significant relationship between some research components. In Raz and Jarglan, as one of the most deprived areas of North Khorasan province, the situation is far more critical than in Pebjnoord as the capital of the province. Because, on the one hand, the institutional capacity is extremely low, and on the other hand, the performance of the institutions, in parallel with their capacity, has had very little effects on the process and institutionalization of sustainable development. Although this pattern is also true in Bojnord, but to some extent its situation is more hopeful and more favorable than Raz and Jarglan.

The results of this research are related to the study areas and its generalizability may not be confirmed in other regions of the country and the world because there is a big difference between the development process and the degree of development of societies as well as the executive systems of countries. Finally, executive proposals have been presented, such as "providing incentives for institutions to improve service delivery and more optimal and desirable functions."

Travertine refers to all non-marine carbonate sediments consisting of calcite/aragonite formed by calcium and CO2-rich fluids under surface conditions and low pressure. Travertine deposition takes place as a result of the decomposition of calcium bicarbonate and the release of CO2 gas. Based on elemental geochemistry, origin of carbon dioxide gas and composition of stable isotopes, travertines are divided into two groups: thermogenic and meteogenic. Studies of stable isotopes of carbon and oxygen play a fundamental role in determining the origin and type of travertine. Thermogenic travertines, which are often associated with young volcanic areas, were deposited from medium to high temperature fluids and their carbon isotope composition is heavy. While meteogenic travertines are formed from relatively low temperature fluids and their carbon isotope composition is light.

In this study, the mineralogical, geochemical and isotopic characteristics of Borjlu travertine located in the Alborz-Azerbaijan magmatic belt in the northwest of Iran have been investigated based on field and laboratory studies. In this research, petrographic studies were done using microscopic thin sections by polarizing microscope. The samples were analyzed by inductively coupled plasma mass spectroscopy (ICP-MS) to determine Ba and Sr contents. X-ray diffraction (XRD) and scanning electron microscope (SEM) imaging have also been used to study the mineralogy of the samples. The analysis of stable isotopes of carbon and oxygen has been done to determine the isotopic composition of carbonate minerals by mass spectrometer (MS) method.

Three facies including crystalline crust in the form of alternating light and dark layers, raft in the form of discontinuous layers, and shrub consisting of branching structures with rounded and buttons ends can be seen in Barjelo travertine. The result of XRD analysis from the crystalline crust shows that they are formed from pure calcite. SEM image shows the limited presence of microbial accumulations on the surface of calcite crystals. Petrographic studies of the crystalline crust part of travertine show that calcite crystals have grown in three forms of lamellar prisms, fibrous crystals and micrite grains. Some sections also indicate the alternating growth of crystalline crust and shrub facies. The average values of Ba and Sr in the travertine samples are 40.22 and 563.89 ppm, respectively. The values of δ13C(VPDB) and δ18O(VPDB) isotopes of the samples range from +1.44‰ to +2.19‰ and -14.39 to -16.51‰, respectively. The calculated values of δ18O(SMOW) and δ13C(CO2) for the samples show changes from +13.84‰ to +16.02‰ and -7.87 to -8.77‰ respectively.

The comparison of Ba and Sr contents indicates the thermogenic origin of Borjlu travertine. Although the δ13C(VPDB) positive values in Borjlu travertine indicate its thermogenic origin, its values are lower than typical thermogene travertines. Comparison of δ13C(VPDB) and δ18O(SMOW) values showed that Borjlu travertine samples located in the field of thermogene and meteogene travertines, which indicates the mixing of two fluids with heavy and light isotopic composition. The calculated values of δ13C(CO2) indicate the inorganic and internal origin of CO2 in the travertine-forming fluid. Also, in the isotope composition diagram of δ13C(VPDB) versus δ18O(VPDB), carbonate rocks are shown as the source of CO2 gas for the formation of Borjlu travertine. Some field evidences, such as the formation of crystalline crust and shrub facies, the presence of a hot spring with a relatively high temperature in the studied area, and the presence of a geothermal reservoir in the depth are signs of active hydrothermal phenomena in the area. It is thought that the presence of limestone units in the region and their contact with the fault system has provided the possibility of infiltration and circulation of hydrothermal fluids containing CO2 inside them. In this way, the bicarbonate ions necessary for the formation of travertine has been provided by decarbonation and dissolution of these carbonates. It seems that the fault system acted as a conduit for the migration and ascent of fluids containing calcium bicarbonate towards the surface. The mixing of this fluid with meteoric waters near the surface caused lighter isotopic composition of the ascending fluid. Based on isotope composition of travertine samples, the temperature of outflowing fluid is estimated about 70 °C.

Understanding regional tectonics and characterizing local processes greatly benefit from local measurements of paleo-stress direction. Mathematical techniques based on the inversion of fault slip data are one of the frequently used techniques for detecting the direction of the paleo-stress (Balansa et al., 2022; Zhang et al., 2020; Angelier 1994; Jentzer et al., 2017). The deformed area of Koleh-Sangi is situated structurally in the centert of the Sistan Suture Zone, north of Zahedan. Sistan Suture Zone is a most intricate structural regions that several research have been conducted to comprehend the past deformation of this area. Given that the studied region has several faults and fractures, the orientation of paleo-tectonic stresses has mostly been dependent on the orientation of faults and the relative movement along them, and the results of structural analysis and paleo-stress investigations were ignored. Therefore, it is essential to conduct this research, and its findings may contribute to a better knowledge of the Sistan Suture Zone.

A kinematic process results in slickenside and movement along the fault. For many years, structural investigations have employed the kinematic study index to identify several types of paleo-stress, including fault lines, shear zones, veins, and stylolites. The slickenside fault planes can be employed as movement or kinematic markers (Hancock 1985; Roberts 1996; Roberts and Michetti 2004). The range of structural components, such as slickenside, have been considered in the reconstruction techniques for paleo-stress. The four stress tensor parameters are based on the amount and direction of slide on the fault plane (Angelier, 1989; 1991). These parameters, which include the principal stress axes σ1≥σ2≥σ3, are introduced in the form of the following equation with the title R, which is the same as the ratio of the magnitude of the stress ellipse. These parameters depend on the ratio of the magnitude of the intermediate stress σ2, the maximum σ1, and the minimum σ3 principal stresses.

It was attempted to take the spatial features of faults and their related structures from four sites with varied ages of deformed rocks to calculate the paleo-stress parameters in the different area (areas A, B, C and D). According to the main goal of the article, it has been tried to take into account the early and late geological events. The properties of the fault planes, the slickenside, as well as the fault's Cross-cutting relationships and movement, were collected during the field surveys. The stress ratio (φ) has been fluctuating between 0.3 and 0.9 based on observations made and the interpretation of the data acquired in the MIM software from four areas with varying rock ages. The maximum and minimum trend and plunge of the computed axes were drawn on the contour diagram for each range to produce a specific pattern to estimate the orientation of the stress axes, and the most compatible planes for the axes were identified on the diagram.

The earliest rock formations in the area, were impacted by a compressional phase that occurred at an N84°E.The second phase of progressive deformation indicates the N59°E.Its compressional direction has been determined to be N10°. This compressional direction is consistent with both the compressional trend determined by GPS (Vernant et al, 2004) and the trend obtained for the major faults in this region,) such as the Zahedan dextral strike-slip fault, the Nosratabad dextral strike-slip fault and reverse faults with a north-northwest strike (Berberian et al., 2000; Walker and Khatib, 2006). According to the available data and earlier investigations, this deformation phase occurred during or after the Eocene and has persisted up to the current day.A transtension regime is visible in the youngest phase in Paleocene and Oligocene-Miocene outcrops. This phase may be brought on by normal faults along fold axes, on the hanging wall of thrust faults and associated with north-south strike-slip faults. The latest stage of deformation in the area may be explained by the presence of the Zahedan strike-slip fault, which has a significant amount of displacement throughout its length.

Very few palynological studies have been conducted on the Nayband Formation, as a part of the Upper Triassic coal deposits of central Iran. Mousavi, 2002 (seen in Aghanabati 2004, pp. 209-210) considered the abundance and diversity of marine palynomorphs compared to terrestrial types indicate the shallow sea environment for Nayband Formation. Cirilli et al., 2005 attributed the Nayband Formation palynofloras to tropical plants such as Bennettitales, Matoniaceae, and Marattiaceae accompanied by characteristic forms of the Siberian Province. Sabbaghiyan et al., 2015 examined the palynology of the Nayband Formation, Tabas Block. They believed the associated marine palynomorphs (dinocysts), accompanied by spores indicate a nearshore depositional environment for the Late Triassic deposits. Sajjadi et al., 2015 studied the palynology of the Nayband Formation, Kamar Macheh Kuh, southeastern Tabas. They concluded that the abundance of ferns and Coniferophytes in parent flora implies that the host strata accumulated under a moist warm climate with progressively decreasing temperatures during Late Triassic. Sabbaghiyan et al., 2020 investigated the palynology of the Upper Triassic Bidestan and Howz-e-Sheikh members in Tabas Block. They believed that co-occurrence of marine elements (dinoflagellate cysts, bivalves, corals, and gastropods) with terrestrial elements (spores and pollen) shows a shallow marine depositional environment for the Nayband Formation.
A total of 62 samples were collected from the Nayband Formation (Qadir Member), at exploratory well no. 948b. All samples were prepared following standard palynological processing procedures (Phipps & Playford, 1984), including HCl (10-50%) and HF (40%) utilized for the dissolution of carbonates and silicates, respectively. Then the residues were saturated with ZnCl2 solution (specific gravity 1.9 g/ml) for density separation. All the residues were sieved with a 20 μm mesh sieve previous to making strew slides. Three slides for each preparation were examined by a transmitted light microscope.
To reconstruct the paleoclimate of the Nayband Formation (Qadir Member) in the south of Tabas, 62 samples were collected from exploration well no. 948b for palynological investigations. The assemblage of diverse palynomorphs includes spores and pollen of land plants, dinoflagellate cysts, foraminiferal test linings, acritarchs, and algal spores with moderate to good preservation. The parent plants of existing miospores show that the diversity and abundance of ferns is 64%, cycadophytes 16%, lycophyta 9%, conifers 4%, gynophytes 4%, pteridospermophyta 2% and Bryophyta 1%. The maximum diversity and relative abundance belong to miospores attributed to ferns (64%), which indicates the predominance of warm to semi-warm climate with high humidity at that time of deposition. Based on the model of Sporomorph EcoGroups, miospores typifying all six plant communities are present in the studied strata, but the highest frequency is related to the lowlands SEGs. To reconstruct the paleoclimate variation, the large quantity percentage of four main plant groups (Hydrophilic, xerophilic, Thermophilic, Psychrophilic) was calculated and the paleoclimate study was determined by the pattern of relative abundance of drier/wetter and warmer/cooler elements. The consequences of these calculations approve the warm to semi-warm climate with high humidity conditions. Also, the paleogeographic position of Iran during the Late Triassic in the southern active margin of Eurasia (Turan Plate) is another confirmation of this type of climate.
Diverse palynomorphs with high abundance including spores, pollen, dinoflagellate cysts, foraminiferal test linings, acritarchs, and algal spores with moderate to good preservation are present in the studied material. Inferred natural relationships of the Nayband sporae dispersae imply derivation from a diverse parental flora such as ferns, Conifers, Lycophyta, Cycadophytes, Gynophytes, Pteridospermophyta, and Bryophyte. Ferns have relative abundance and maximum diversity in the composition of the vegetation around the sedimentary environment. It implies that the host strata accumulated under moist warm to semi-warm climates. In addition to, the high ratio of warmer/cooler, wetter/drier palynomorphs and the palaeogeographic position of Iran during the Late Triassic in the southern active margin of Eurasia (Turan Plate) and the location of Iran at a latitude of about 35°N, all confirm the above results that hot and humid climate prevails.

Fluid inclusions provide valuable evidence of the formation temperature of minerals, the pressure on their formation environment, the fluids densities that make up the minerals, and the chemical composition of the mineralizing fluids. This data can be used to interpret temperature history, maturity, determination of diagenetic environment, cementation timing, and hydrocarbon migration related to burial history.

In this study, the cores of Asmari reservoir of 7 wells from Ahvaz field (AZ) were used. After checking the appearance characteristics of the samples, 19 double-polished sections with a thickness of 200 to 300 micrometers were prepared. In order to perform microthermometric analysis, at first, all samples were placed in acetone for 24 hours. In the following, after separating the double polished samples from the slide, in order to completely remove the surface contamination, the samples were placed in an ultrasonic device for five minutes in distilled water. After the initial investigation of the occurrence of fluids inclusions in the studied samples, regardless of the size of the fluids involved, 54 intermediate loads of fluids were selected to conduct microthermometric studies. All microthermometric data were obtained using cooling and heating operations on the involved fluids using a Linkam THMSG 600 model stage placed on an Olympus microscope. In addition, in order to determine the amount of UV reflection in the Petroleum Inclusions in the study, the UV light source model U-RFL-T placed on the Olympus microscope was used. After performing microthermometric operations on the fluid’s inclusions, the selected samples were selected for Raman laser spectroscopy analysis to accurately determine the liquid and vapor phases of the Petroleum Inclusions. It should be noted that Raman laser spectroscopy analyzes were performed on microthermometric analyzed samples. All measurements were made using a LABRAM model Raman spectrometer (ISA Jobin Yvon) available in the Fluid inclusions Laboratory of Montanuniversitat University.

Petrographic studies All the samples were subjected to petrography study, which is in terms of the types of single-phase gas, single-phase liquid, two-phase liquid-rich (oil) intermediates. In these samples, hydrocarbon materials can be seen scattered and filling fractures. In terms of origin, it can be seen in different and varied types, primary and secondary false. Microthermometric studies Microthermometry was performed on 54 fluids inclusions. The homogenization temperature of fluid inclusions is between 50 and 362 degrees Celsius. The samples of the Asmari reservoir show the melting temperature of the last ice crystal between -22 and 13.9. The degree of salinity is calculated to be 0.16 to 35% by weight equivalent to table salt. API study In the samples selected from the Asmari reservoir in Ahvaz field, 54 fluid inclusions were identified. These fluid inclusions emitted the following fluorescence spectrum under UV light. The frequency of reflective color is related to green with a value of 55%, which is in the range of 30-40 API degrees, and the value of 40% belongs to blue color, which indicates the range of API degree 40. -50 and only 5% of these colors belong to the yellow color, which indicates the API degree in the range of 20-30. Therefore, in the samples of the Asmari reservoir, the green color with a frequency of 55% has a density of 0.82 to 0.74 g/cm3, which generally indicates oil with a light density. Also, in the second category of these samples, the abundance of fluorescent reflective color, blue color with an abundance of 40%, with a density of less than 0.74 g/cm3, is considered an extremely light oil. Finally, the lowest reflective color abundance of Asmari reservoir samples is yellow with 5% density of 0.9 to 0.82 g/cm3, it is considered a medium density oil. Raman spectroscopy The calculation of liquid phase salinity in petroleum inclusions cargoes using the Raman laser spectroscopy method is dependent on the geometric shape of the spectrum obtained from the liquid phase present in the petroleum inclusions. According to the Cauchy-Lorentz scattering, the Raman spectrum for pure water shows three peaks at cm-13220, cm-13433 and cm-13617. In the samples that were analyzed by Raman spectroscopy, they indicate hydrocarbon compounds in the fluid inclusions.

Based on the petrographic studies conducted on 19 samples (54 fluid inclusions) according to their diversity (primary, secondary), it indicates and confirms the different compositions of the activity of different phases of Asmari reservoir charging. Based on the data obtained from the microthermometric studies, the physicochemical properties of the reservoir, including the last ice melting temperature, homogenization temperature, and salinity of the reservoir were determined. Based on the physicochemical properties of the Asmari reservoir, it shows two temperature ranges, which can be concluded that this reservoir was charged during two phases in two different time periods. One of the reasons confirming this conclusion can be mentioned that the oil of this reservoir has two origins. Also, based on the composition of the phases in the fluid inclusions (two-phase, three-phase with oil, etc.), it is possible to predict the path of charging the reservoir.

The megacity of Tehran, Iran's capital, is positioned on the southern slope of the central part of the Alborz Mountain range. This range displays active tectonics, resulting in a history of destructive earthquakes, quaternary deformation, massive ancient landslides, and geodetic phenomena. Earthquake movement and deformation can lead to the emergence of numerous secondary geological and non-geological hazards. This article presents a revised map showcasing the fault distribution in the northern region of the Tehran megacity, based on a synthesis of both current and novel information.

This study entails the formulation of a fault map encompassing the northern sector of Tehran city, employing a cartographic scale exceeding 1:20000. This endeavor capitalizes on geological maps, historical as well as instrumental seismic records, and both extant and novel fault-related insights extrapolated from satellite image scrutiny, aerial photography archives dating back to 1955, and comprehensive field investigations. Subsequently, instances of quaternary faulting have been delineated for salient fault lines. Through a comprehensive examination of strategies aimed at mitigating the risk posed by surface rupture events, heightened attention has been accorded to, and an evaluation has been undertaken of this peril within the delineated study expanse. Elaborated information is expounded upon within the corresponding Persian manuscript.

Figure 1 illustrates the revised cartographic representation delineating the geographic positioning of pivotal faults situated within the northern precinct of Tehran. Of paramount significance within this cartographic presentation is the discernment of fault line continuities previously introduced but whose terminal extents remained obscure. Moreover, an expansive network of fractures or subsidiary faults aligned with the North Tehran fault system has been meticulously charted, particularly in the hangingwall segment thereof, hitherto unreported in extant literature.The North Tehran fault, alongside the Pardisan, Niavaran, Mahmoudieh, Davoodieh, and Kan faults, the latter boasting the most extensive reach, collectively constitute the foremost fault trends imparting significant geological risk within the confines of Tehran city. Creating comprehensive geoscience data systems tailored to urban scales emerges as a viable solution to address myriad requisites, encompassing the effective management of contemporary urban risks.Preliminary inquiries substantiate the assertion that a minimum of twenty prominent public and private hospitals within Tehran directly confront the hazard of surface rupture events.Fig. 1. The updated map of the faults in the northern zone of Tehran city is placed on the digital elevation model. The fault information is from Berberian et al. (2014), Abbasi and Farbad (2009), Talebian et al. (2017) and other sources, along with observations made and the analysis of satellite images and aerial photographs in this research. At the base of the map, the built areas of Tehran are based on 1:25,000 topographic maps of the country's mapping organization, which do not show the full extent of the current city of Tehran.

Contemporary perspectives pertaining to the computation and observation of fault setbacks underscore the imperative of meticulous fault location mapping prior to urban development. While subsurface methodologies hold promise for generating these highly accurate maps within regions characterized by youthful sedimentary deposits, historical data gleaned from fault observations provide valuable context. Given sufficient financial resources, such historical data can corroborate or negate the veracity of known fault lines. Absent such resources, judicious evaluation compels the prioritization of fault line delineation and the concomitant alignment of construction codes therewith.Of paramount import within the context of the presented map is the recognition of fault trend continuities previously introduced, the onward trajectory of which remained enigmatic. Additionally, an extensive matrix of fractures or attendant subsidiary faults inherent to the North Tehran fault system has been methodically charted, with a notable focus on its hanging wall portion hitherto unpublished.The Northern Tehran fault, in conjunction with the Pardisan, Niavaran, Mahmoudieh, Davoodieh, and Kan faults, the latter exhibiting the most expansive extent, collectively constitute the preeminent fault trends engendering pronounced geological risk within the confines of Tehran city. It is noteworthy that although faults such as the Mosha fault, situated at a minimum distance of 30 km from Tehran city, are acknowledged as influential seismic sources for the city, the paramount concern lies in the evaluation of surface rupture hazard, wherein those faults positioned within the urban area assume a markedly more critical role.