Tehran Region Research Articles

Identification of dust sources inside and outside of Iran affecting air quality in the Tehran region

Introduction: Recent climate changes and droughts have exacerbated the impact of dust sources globally, necessitating a thorough understanding of their influence on air quality. In Tehran, the interaction between internal dust sources from Iran and external sources from neighboring countries significantly affects air quality. Materials and methods: This study spans a 20-year period (2003-2022), utilizing satellite data and advanced algorithms to analyze dust event trends and patterns. The material and methods section outlines the use of Aqua satellite MODIS sensor data alongside two algorithms to identify dust sources, focusing on Aerosol Optical Depth (AOD) data during peak dust event seasons. Statistical analysis of dust events in 2022 supplements the investigation. Results: The analysis reveals distinct patterns in dust particle origin and transport, highlighting the predominant contribution of internal dust sources from Iran's southern Semnan province and significant input from external sources in Iraq and northern Saudi Arabia. Examining meteorological conditions during severe dust events highlights the role of synoptic conditions, particularly the presence of a tropospheric trough, in facilitating dust transport. Increased convective motions and downburst occurrences in specific regions further exacerbate the spread of dust particles, particularly those originating from external countries and provinces. Conclusion: The conclusion emphasizes the complex interplay between internal and external dust sources and the necessity of understanding dust emission dynamics for effective mitigation strategies. It calls for proactive measures involving local and regional cooperation to mitigate dust pollution's adverse effects on air quality in Tehran and similar urban centers.

Quantifying the features of earthquake clusters in north-Central Iran, based on nearest-neighbor distances and network analysis

The statistical features of earthquake clusters in North-Central Iran (Tehran Region) are investigated, with the aim of quantitatively characterizing the properties of earthquake triggering and allow exploring their possible relations with the tectonic setting of the study area.The nearest-neighbor approach is used for the identification of the earthquake clusters in the space-time-energy domain. This approach permits for a data-driven identification of clusters so that, within multi-event clusters, the features of secondary and higher orders dependent events can be explored. The study is based on a revised dataset that is extracted from the catalog compiled by the Iranian Seismological Center (IRSC) for the period of 1996–2022. In order to exclude the effect of non-tectonic events, which turn out quite numerous within the study region, explosions within quarry-rich areas are removed; the identification of non-tectonic events is performed by considering the normalized ratios of daytime to nighttime events in an iterative removal procedure. According to preliminary analysis of the resulting catalog, an area is selected, within which a satisfactory completeness level is assessed for events with magnitude >2.0. Robust values of the scaling parameters, namely the b-value and the fractal dimension of epicenters, are also computed and are used to calculate the nearest-neighbor distances and to identify the earthquake clusters.The nearest-neighbor method also permits to investigate the internal structure of earthquake sequences, and to differentiate the spatial properties of seismicity according to the different topological features of the clusters structure. The obtained results allow us identifying two macro-areas, approximately separated by the 52°E meridian, which are characterized by different clustering features, namely: high complexity indexes, indicating simple (burst-like) structure of clusters, to the East; low complexity index, corresponding to complex multi-level (swarm-like) structure of clusters, to the West. The complexity measures, borrowed from network theory (i.e. the Closeness and Outdegree Centralization indexes), consistently capture the complexity of the identified clusters, and confirm that the cluster structures have distinct preferred geographic locations. The territorial heterogeneity of the examined clustering properties can be related with the spatial variability of tectonic, structural and geophysical features of the Alborz region, in good agreement with findings from the Alps-Dinarides junction (Northeastern Italy), a region also characterized by a contractional structural setting, mainly including reverse and strike-slip faulting systems, and by moderate to high seismic activity.

Earthquake-induced paleo-landslides in the Tehran Region and its role in assessing the seismic hazard, Iran

In the central portion of the Arabia-Eurasia collision zone, the Tehran domain is positioned at a transitional boundary between seismotectonic zones of the Central Iranian lowland (to the south) and the Alborz highland (to the north). Consequently, numerous destructive seismic events have occurred in this active tectonic domain. This study delves into the tectonic geomorphology of the region within its northern highland domain, specifically focusing on the hanging wall of the E-striking north-dipping North Tehran fault (NTF) zone. Our findings in this northern domain emphasize several prominent topographic scars as significant co-seismic features. These include huge landslides, rockfalls, rock avalanches, and offset geomorphic surfaces and could be present as the main indirect co-seismic morphological features. Within this seismically active region, the extensive dimensions of these geomorphic pieces of evidence reveal the seismic potential of the Tehran Region to experience really strong earthquakes (i.e. M>7.5). These results contrast with the previous Maximum Credible Earthquake (MCE) magnitude estimated for the Tehran Region (i.e. M~7.2) through different approaches in Seismic Hazard Assessments (SHAs). Consequently, the previous SHAs of the Tehran Region might have underestimated the seismic risk, and therefore, it is necessary to conduct an updated and complementary deterministic SHA based on the more detailed seismogenic geological features in this crucial area.

Uncertainty and sensitivity assessments on the inputs of probabilistic seismic hazard assessment: A case study of the North Tehran fault

Probabilistic seismic hazard analysis (PSHA) often incorporates significant uncertainty in its inputs, which have the potential to substantially affect the estimated hazards. To improve the reliability of seismic hazards, the present work examines how these uncertainties impact the variability of PSHA and disaggregation results. For this purpose, uncertainty and sensitivity analyses have been performed for different sites in the Tehran region, with the seismic source of the North Tehran Fault as a case study. The results show that uncertainties in the input parameters have a moderate to significant effect on the PSHA and disaggregation results. The uncertainty and sensitivity analyses of this study provide a better understanding of the various PSHA parameters and their associated uncertainties. Therefore, such analyses establish confidence in the PSHA results and expose the main sources of uncertainty, which enable the prioritization of endeavors to reduce hazard variability.

Recognition of the causative fault of the 2017 MW 4.9 Malard (Tehran, Iran) earthquake from directivity analysis of the recorded ground motions

On December 20, 2017, a light shallow earthquake (Mw 4.9) with a purely strike-slip mechanism occurred on a hidden unknown fault, 30 km west of the city of Tehran. The purpose of this study is to determine the causative fault plane based on the directivity effect that was observed during this shallow crustal depth earthquake, referred to as the Malard earthquake. This was achieved by using data from 96 seismic and accelerometer stations, and employing a variety of methods.For the analysis of the directivity effect, we employed methods including empirical Green's function deconvolution in the frequency domain, inversion of corrected ground motions based on empirical models, and comparison of relative peak ground acceleration and velocity between the mainshock and the largest aftershock. All approaches indicate that the Malard earthquake occurred on a previously unknown fault with a strike of 71°, a steep southward dip, and a confirmed left-lateral strike-slip mechanism, as evidenced by the analysis of aftershock distribution. The earthquake exhibited a strong directivity effect, with rupture propagating unilaterally from the hypocenter to the southwest at a velocity of 2.5 km/s.In addition to enhancing our understanding of active earthquake sources in the densely populated areas of Iran, the findings of this study will also contribute to future earthquake risk assessments in the Tehran region. However, it's important to note that Tehran was situated in the backward zone of the Malard earthquake rupture, where the least ground motion was recorded. Future earthquakes on this fault may exhibit different propagation patterns, toward the city. The determination of a preferred propagation direction can only be achieved probabilistically through the study of a substantial number of earthquakes in the region. The absence of recorded ground motion data will lead to significant uncertainty in predicting the propagation direction of future earthquakes, which must be taken into consideration during hazard analysis.

Spatial correlation models of VS30 values: A case study of the Tehran region

The average shear wave velocity of the top 30 m of soil profile (VS30) is considered as an indicator of local-site effects in seismic hazard assessment (SHA) studies. Previous research works have demonstrated that in addition to actual VS30 values, their spatial correlation characteristics have considerable effects on the estimated values of earthquake intensity measurements, particularly when the seismic risk assessment of spatially distributed assets and infrastructure networks is of interest. Tehran city, in addition to its proximity to several faults, is situated on a variety of sedimentary textures and encompasses a large number of residential buildings and infrastructure networks. The current study utilizes advanced spatial statistics methods and investigates the spatial correlation characteristics of the random field of VS30 values in Tehran. Moreover, by employing a more comprehensive database of VS30 values measured using geoseismic approaches and using eight spatial interpolation methods, a new estimated VS30 map of Tehran city is provided. The geological formations of the study area are also investigated considering the distribution of sample points with different VS30 values. The findings of the current research can be utilized in spatially correlated SHA studies in the Tehran region and can be viewed as a step towards filling the data gap required for seismic risk assessment studies in this region. Moreover, by identifying the local variations in site classes, the findings of the current study can be used for further detailing of geological formations.

Near-surface azimuthal anisotropy using the Rayleigh wave inversion in the Tehran region, Iran

Near-surface azimuthal anisotropy using the Rayleigh wave inversion in the Tehran region, Iran

Active seismogenic faulting in the Tehran Region, north of Iran; state-of-the-art and future seismic hazard assessment prospects

This study summarizes the state-of-the-art investigation into active-seismogenic faulting in the Tehran Region, and presents new complementary data to provide an overall view on potential seismic sources to strike the capital of Iran. The study region lies in the central portion of the Arabia-Eurasia collision zone. The Tehran Region is located in a transitional zone between the seismically active regions of Central Iran to the south and Alborz to the north and exhibits a tectonic context characterized by both dip-slip and strike-slip E-striking fault systems such as the Mosha, Parchin, Garmsar and North Tehran faults. Seismic catalogues record numerous strong and moderate earthquakes in the Tehran Region. Although the mapping of active faults and paleoseismological records have defined the seismic sources of several historical and prehistorical earthquakes, still many of them need to be constrained. Based on successive fault displacements and related microseismicity, five previously unknown or poorly understood major active seismogenic fault zones in the Tehran Region were introduced. From the west to the east, and in both near- and far-field contexts, the Qezel Hessar, Mahdasht-South Karaj, Kuhak-Lavizan, Arakuh, and Kajan define the fault zones. Critically, in the last decades, the rapid urban development in Tehran, including the new settlements of Karaj, Hashtguerd, Pardis, and Parand, has covered some of the surface expressions of these fault zones. The Kuhak-Lavizan fault zone, however, is known to cut across inner city parts of Tehran. Within the Tehran Region, seismicity on these faults demonstrates ongoing active structural evolution. The active faults of Tehran City are generally discussed in three northern, central and southern ∼E-striking basement zones. The major zones, which contain deep-seated faults, are capable of producing moderate to strong seismic events near and within the metropolitan areas of Tehran and Karaj and nearby settlements.

A non-extensive approach to probabilistic seismic hazard analysis

Abstract. We modify the probabilistic seismic hazard analysis (PSHA) formulation by replacing the Gutenberg–Richter power law with the SCP (Sotolongo-Costa and Posadas) non-extensive model for earthquake size distribution and call it NEPSHA. The SCP claimed to model the regional seismicity better than the classical models. The proposed method (NEPSHA) is implemented in the Tehran region, and the results are compared with the classic PSHA method. The hazard curves show that NEPSHA gives a higher hazard, especially in the range of practical return periods. The uniform hazard spectra of NEPSHA provide more spectral accelerations, especially for the medium-height buildings, which are the most common urban structures.

Determining the City-Region’s Boundary as an Adequate Scale of Spatial Planning: Case Study of Tehran Metropolitan Region, Iran

The development and expansion of 20th-century urbanization have led to large-scale populated regions that did not exist prior to this era. City-region is a kind of 20-century large-scale concept recognized as the most advanced stage of urban development. Regardless of its long history, the concept of city-region does not enjoy a standard definition. In this vein, the present paper seeks to provide a suitable framework for the primary argument determining the city-region boundary. Indeed, understanding the boundary allows planners to study a precise area, resulting in refining the concept and meticulously planning. Therefore, as applied research, it is aimed to respond to the practical problem in spatial planning by expanding and developing the city-region’s knowledge base. The paper has a mixed-method, using content analysis, the Structural Equation Model techniques, and Hot spot analysis. The results introduce six factors for determining the city-region’s boundary, including economic self-sufficiency, community relation, regional competitiveness, balanced management, services and infrastructure capacities, and the space of flows. The research’s flexible model allows planners to adjust it based on their field of study, inferring that the proposed model is utterly comprehensive; however, having access to different databases, scholars may encounter a challenge to adapt indicators. Accordingly, indicators should be customized based on general ones. In this study, the indicators are customized according to Iran’s data sources, and the output framework is tested on the Tehran region that deals with inefficiencies in urban and regional planning.

Ten-Year Survival of Breast Cancer in Iran: A National Study (Retrospective Cohort Study)

Purpose: This study aimed to estimate the 5- and 10-year survival rates of breast cancer in Iran. Methods: This retrospective cohort study was performed in 2019 on breast cancer patients registered in the national cancer registry system of Iran during 2007–2014. The patients were contacted to collect their information and status (alive or dead). Age and pathological type of tumor were categorized into five groups, and the place of residence was divided into 13 regions. The Kaplan-Meier method and the Cox proportional hazards model were used for data analysis. Results: A total of 87,902 patients were diagnosed with breast cancer during the study, 22,307 of whom were followed-up. The 5- and 10-year survival rates of the patients were 80% and 69%, respectively. The mean age of the patients was 50.68 ± 12.76 years (median age, 49 years). About 2.3% of the patients were male. The 5- and 10-year survival rates were 69% and 50% in men, respectively. The highest survival rate was reported in the age group of 40–49 years, and the lowest rate was found in the age group of ≥70 years. Of all pathological types, 88% were found in the invasive ductal carcinoma group; the highest survival rate was reported in the noninvasive carcinoma group. The highest survival rate was reported in the Tehran region and the lowest in the Hamedan region. Based on the results, the Cox proportional hazards model, sex, age group, and pathological type were statistically significant differences. Conclusion: This nationwide study performed on breast cancer patients indicated an improvement in the overall survival rate of these patients over the past years (the 5-year survival rate increased from 71% in 2011 to 80% in the present study), which might be attributed to advances in cancer management.

Risk and damage-based optimal design of storm sewer networks using rational and fully dynamic methods, a case study (Tehran region 2).

In this study, the risk analysis is used to determine the return period in which the design cost plus the damage risk cost is minimum. The damage includes the roads and traffic, the lawn areas, and the residential and commercial buildings. The traffic damage is based on two factors, time of delay and social negative impacts. The nonlinear reservoir model is used to convert the rainfall into runoff and the dynamic wave model is utilized to perform the network hydraulic simulation in stormwater management model (SWMM) software. This model is defined as an appropriate model. This model was applied in the risk analysis of a region in Tehran to obtain the optimal return period design. The results indicated that the optimal return period is 10 years. The rational method was also applied to the same region and same return period, but the total design cost of the rational method was greater by 5%. The damage due to the traffic include financial damages due to delays and loss of fuel resources in addition to the dissatisfaction of people due to the psychological burden.

Estimating greenhouse emissions from sanitary landfills using Land-GEM and IPCC model based on realistic scenarios of different urban areas: a case study of Iran.

This study examined the emission of greenhouse gases from municipal solid waste disposal centers in different regions of Iran based on different scenarios. Assuming landfill site opening in 2012 and considering the 20-year plan period for its usage, the amount of wastes entering the landfill site was calculated for 2012-2032. For calculating the production of methane (CH4) and other gases during different years of the project, Land-GEM and IPCC model were used. We defined 9 scenarios for these two models based on the growth rate of population and waste generation. The results revealed that the lowest amount of gas emission in nine scenarios by Land- GEM model was related to non-methane organic compounds (NMOCs). According to the results obtained, the total emissions of greenhouse gases from sanitary landfills for Iran in 2032 were 3,844,000 Mg/year, the largest and lowest amounts of gas emission were related to Tehran region, 860,400 Mg/year, and the South Coast area of the country,138,200 Mg/year, respectively. The major section of the gas production in both landfills was related to greenhouse gas and carbon dioxide emissions. The difference in gas production in the studied regions was due to differences in the percentage of moisture and organic compounds.

A backbone probabilistic seismic hazard analysis for the North Tehran Fault scenario

In this study, a comprehensive probabilistic seismic hazard analysis (PSHA) using both time-independent and time-dependent approaches is carried out for the North Tehran fault (NTF) scenario. We applied a novel backbone approach to consider the epistemic uncertainty associated with the ground motion estimates. For this purpose, a backbone ground motion model (GMM) is selected using the data-driven deviance information criterion (DIC) method, and the logic tree branches are populated with the backbone GMMs that are added/subtracted from a scale factor. The results show that the estimated ground motions follow the spatial pattern of the NTF and decrease in the far-field, but this spatial pattern is also influenced by the amplification from site effects, in the southern alluvium part where the sites are classified as the category D of NEHRP. Furthermore, the effect of the multi-segment rupture is investigated using a cascading model. The results show that the ground motion values are increased by 20–40% and 10–20% for the 10%-in-50 years and 2%-in-50 years, respectively, particularly at near-fault distances. The results of this study are generally compatible with the previous seismic hazard studies for the Tehran region. Therefore, the novel backbone approach used in this study provides a more reliable seismic hazard estimates for the Tehran metropolis.

Rapid Estimation of the Epicentral Distance in the Earthquake Early Warning System around the Tehran Region, Iran

Correction| May 20, 2020 Rapid Estimation of the Epicentral Distance in the Earthquake Early Warning System around the Tehran Region, Iran Sahar Nazeri; Sahar Nazeri Search for other works by this author on: GSW Google Scholar Zaher Hossein Shomali Zaher Hossein Shomali * *Corresponding author: Hossein.Shomali@geo.uu.se Search for other works by this author on: GSW Google Scholar Seismological Research Letters (2020) 91 (4): 2438. https://doi.org/10.1785/0220200113 Article history first online: 20 May 2020 Connected Content Errata: Rapid Estimation of the Epicentral Distance in the Earthquake Early Warning System around the Tehran Region, Iran Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Tools Icon Tools Get Permissions Search Site Citation Sahar Nazeri, Zaher Hossein Shomali; Rapid Estimation of the Epicentral Distance in the Earthquake Early Warning System around the Tehran Region, Iran. Seismological Research Letters 2020;; 91 (4): 2438. doi: https://doi.org/10.1785/0220200113 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search nav search search input Search input auto suggest search filter All ContentBy SocietySeismological Research Letters Search Advanced Search We discovered that there are minor typos with equations (3) and (4) in Nazeri and Shomali (2019), the equations are accidentally reversed, and the correct ones are (Yamamoto et al., 2012): (3)logΔ=−0.50 logB+1.96,(4)logΔ=−0.49 logC+1.83. View Original Article You do not currently have access to this article.

A Study of the Effects of Lifestyle Changes on Urban Trip Generation with an Approach to Futures Studies: A Case Study of Tehran Region 6

This research is a descriptive analytical study. The goal was to identify the key factors that affect lifestyle changes and urban trip generation. To achieve this goal, we used two components (pattern, value), 20 criteria (social, economic, cultural, psychological, political, etc.), and 56 variables. For data analysis, the Delphi method, cross-impact analysis and MICMAC were used. The results showed that 25 factors were key factors affecting urban lifestyle changes and urban trip generation. These factors, in order of priority, were: increasing income level of people; more welcoming to urban residents from well-kept homes and high-quality residential neighborhoods; changing role of streets for a new type of recreational trips apart from serving traffic;increasing number of young and adolescents in the region; increasing daily, monthly, seasonal and annual purchases from large retail stores and luxury shopping malls away from downtown; increasing residency of people in new and high-quality urban areas away from the central areas of the city; increasing rate of apartment living and people’s preference to stay in apartments rather than single-family houses; increasing number of single people; increasing non work-related trips, etc. Moreover, the results showed that changes in patterns lead to changes in values and, ultimately, lifestyle changes and increased urban trip generation. Abstrak. Penelitian ini adalah penelitian deskriptif analitik. Tujuan dari penelitian ini adalah untuk mengidentifikasi faktor-faktor kunci yang mempengaruhi perubahan gaya hidup dan generasi perjalanan perkotaan. Untuk mencapai tujuan ini, kami menggunakan dua komponen (pola, nilai), 20 kriteria (sosial, ekonomi, budaya, psikologis, politik, dan lain-lain), dan 56 variabel. Untuk analisis data, digunakan metode Delphi, analisis dampak silang dan MICMAC. Hasil penelitian menunjukkan ada 25 faktor yang merupakan faktor kunci yang mempengaruhi perubahan gaya hidup perkotaan dan generasi perjalanan perkotaan. Faktor-faktor ini, dalam urutan prioritas, adalah: peningkatan tingkat pendapatan masyarakat, peningkatan sambutan penduduk kota yang berasal dari rumah yang terawat baik dan lingkungan perumahan yang berkualitas tinggi, perubahan peran jalan untuk perjalanan rekreasi jenis baru selain melayani lalu lintas, perluasan kelompok usia muda (kenaikan jumlah kaum muda dan remaja) di wilayah tersebut, peningkatan belanja harian, bulanan, musiman dan tahunan dari toko ritel besar dan pusat perbelanjaan mewah yang jauh dari pusat kota, peningkatan jumlah penduduk di daerah perkotaan baru dan berkualitas tinggi yang jauh dari pusat kota, kenaikan tingkat kehidupan di apartemen dan preferensi orang untuk tinggal di apartemen daripada di rumah keluarga tunggal, penambahan jumlah orang lajang, kenaikan perjalanan yang tidak berhubungan dengan pekerjaan, dan lain-lain. Selain itu, hasil menunjukkan bahwa perubahan pola tersebut menyebabkan perubahan nilai dan, pada akhirnya, perubahan gaya hidup dan peningkatan generasi perjalanan perkotaan. Kata kunci. Gaya hidup, generasi perjalanan perkotaan, studi masa depan, metode Delphi.

Rapid Estimation of the Epicentral Distance in the Earthquake Early Warning System around the Tehran Region, Iran

ABSTRACT The estimation of epicentral distance is a critical step in earthquake early warning systems (EEWSs) that is necessary to characterize the level of expected ground shaking. In this study, two rapid methodologies, that is, B‐Δ and C‐Δ, are evaluated to estimate the epicentral distance for use in the EEWSs around the Tehran region. Traditionally, the B and C coefficients are computed using acceleration records, however, in this study, we utilize both acceleration and velocity waveforms for obtaining a suitable B‐Δ and C‐Δ relationships for the Tehran region. In comparison with observations from Japan, our measurements fall within the range of scatter. However, our results show a lower trend, which can strongly depend on the few numbers of events and range of magnitude (small‐to‐moderate) of earthquakes used in the current research. To improve our result, we include some large earthquakes from Iran, Italy, and Japan with magnitude larger than 5.9. Although the optimal trend is finally obtained by fitting a line to the distance‐averaged points, we conclude that the same trend and relationship as Japan can be used in Tehran early warning system. We also found that B and C parameters are strongly compatible to each other. As time windows of 3.0 and 0.5 s after the P onset are chosen respectively to compute the B and C values, so by selecting the C parameter as a proxy of B parameter to estimate the epicentral distance, we may save significant time in order of about 2.5 s in any earthquake early warning applications.

PERFORMANCE ANALYSIS OF HYBRID SOLAR-WIND RO-MSF DESALINATION SYSTEM

Introduction: Water, energy, and the environment are three important elements of sustainable development. Production of potable water using desalination technologies powered by renewable energy systems could help solve water scarcity in remote areas with shortages of water or conventional energy sources, or in large cities with air pollution. Hybridization of solar and wind could increase the sustainability and availability of renewable energy sources and reduce energy costs. Additionally, hybridization of reverse osmosis (RO) and MSF could increase efficiency and desalinated water quality and decrease desalinated water cost. Materials and Methods: The research method in this paper is based on modeling, computer simulation, and optimization with MATLAB software, and manufacturing and evaluating the plant at the Tarbiat Modares University Renewable Energy Laboratory. Results: The process of manufacturing the MSF system, solar panel structure, and wind turbine was explained and modeling and optimization results were presented. Testing results of the plant were mentioned, as were the produced power of wind turbine simulated and plant performance evaluated under the environmental conditions of the Tehran region. The rate of fresh water production under changing feed water salinity was evaluated and the real costs of fresh water produced ($/m3) were estimated. At the end of this section, model results and test results were compared. Conclusion: Hybridization of RO and MSF systems with wind and solar energy resources led to increased system reliability and flexibility and higher produced drinking water quality. The desalinated water cost was 1.35 $/m3 in theory and 1.5 $/m3 for actual conditions. Hybridization of wind, solar, RO, and MSF showed proved the best choices to minimize water cost compared to fossil fuel RO or MSF, wind RO, wind MSF, solar RO, solar MSF, or fossil fuel RO-MSF. Hybridization of RO and MSF would result in better economics and operation characteristics than those corresponding to MSF. Water cost can be reduced by 23 to 26% of that of a sole MSF process and the amount of desalinated water produced by the hybrid RO-MSF system is much greater than that of MSF. A comparison of theory outputs and experimental test results showed very good agreement between measured and model data. The test results of the manufactured hybrid solar-wind RO-MSF justified theory results.

PERFORMANCE ANALYSIS OF HYBRID SOLAR-WIND RO-MSF DESALINATION SYSTEM

Introduction: Water, energy, and the environment are three important elements of sustainable development. Production of potable water using desalination technologies powered by renewable energy systems could help solve water scarcity in remote areas with shortages of water or conventional energy sources, or in large cities with air pollution. Hybridization of solar and wind could increase the sustainability and availability of renewable energy sources and reduce energy costs. Additionally, hybridization of reverse osmosis (RO) and MSF could increase efficiency and desalinated water quality and decrease desalinated water cost. Materials and Methods: The research method in this paper is based on modeling, computer simulation, and optimization with MATLAB software, and manufacturing and evaluating the plant at the Tarbiat Modares University Renewable Energy Laboratory. Results: The process of manufacturing the MSF system, solar panel structure, and wind turbine was explained and modeling and optimization results were presented. Testing results of the plant were mentioned, as were the produced power of wind turbine simulated and plant performance evaluated under the environmental conditions of the Tehran region. The rate of fresh water production under changing feed water salinity was evaluated and the real costs of fresh water produced ($/m3) were estimated. At the end of this section, model results and test results were compared. Conclusion: Hybridization of RO and MSF systems with wind and solar energy resources led to increased system reliability and flexibility and higher produced drinking water quality. The desalinated water cost was 1.35 $/m3 in theory and 1.5 $/m3 for actual conditions. Hybridization of wind, solar, RO, and MSF showed proved the best choices to minimize water cost compared to fossil fuel RO or MSF, wind RO, wind MSF, solar RO, solar MSF, or fossil fuel RO-MSF. Hybridization of RO and MSF would result in better economics and operation characteristics than those corresponding to MSF. Water cost can be reduced by 23 to 26% of that of a sole MSF process and the amount of desalinated water produced by the hybrid RO-MSF system is much greater than that of MSF. A comparison of theory outputs and experimental test results showed very good agreement between measured and model data. The test results of the manufactured hybrid solar-wind RO-MSF justified theory results.

Three-Dimensional P-Wave Velocity Structure of Tehran from Local Micro-Earthquake Tomography

Tehran region is located at the southern foothills of central Alborz Mountains which is one of the most seismically active regions due to the convergence between the Arabian and the Eurasian plates. In this study, 3-D crustal velocity structure of Tehran region was investigated using first P-wave arrival times of events with magnitudes less than 4. Data used was recorded by the stations from Tehran Disaster Management and Mitigation Organization, Iranian Seismological Center and International Institute of Earthquake Engineering and Seismology from 2004 to 2018. In order to obtain the crustal velocity structure of Tehran, iterative, damped least-squares method was used to solve/obtain earthquake parameters and velocity structures, simultaneously. Final results show three tectonic characteristics in the study area including high velocity anomalies in northern and eastern Tehran Mountains, and low velocity anomaly in triangular Tehran basin, so that the separation of the eastern Tehran Mountains and Tehran basin is especially sharp in cross-section profiles. Moreover, some low velocity anomalies are appeared around major faults in the study area (e.g. North Tehran Fault). The tomographic maps also show that the Tehran region contains of an upper crust layer with the thickness of 6 km which is located over middle crust layer bedrock with constant velocity up to 15 km. This upper crust layer consists of a sedimentary layer (~ 3 km thickness) overlaid a basement layer. Moreover, the thick and thin upper crust layers are separated by North Tehran and Kosar/Ghasr-Firooz faultsystems from the Tehran basin, respectively.