Showing 203 results for Type of Study: Original Research
Miss Sooror Mazraeasl, Mr Farzad Akbari, Ms Elahe Iraniasl, Miss Leila Hosseini Shafei,
Volume 18, Issue 1 (5-2024)
Abstract
Groundwater is one of the main sources of water supply for agriculture, drinking and industry in Iran, especially in areas with arid and semi-arid climates. Therefore, due to the high importance of groundwater resources, it is necessary to know the hydrodynamic parameters in order to determine the natural flow of water and manage the optimal utilization of groundwater resources. Considering the role of the Daloon-Meydavood aquifer in providing part of the water needed in the study area, especially for agricultural purposes, the hydrodynamic parameters of this aquifer were estimated using the methods of grain size analysis, geophysics and pumping test. The parameters were calculated by all three methods and validated using the flow rate of the exploitation wells. In all three methods, the hydrodynamic parameters (Hydraulic conductivity, Specific yeild, transmissivity coefficient) are the highest in the north and northeast and the lowest in the south and northwest. The results showed that 2 methods including grain size analysisand pumping test had the most similarity with the discharge map of the exploitationwells.
Dr Sayed Ali Asghari Pari,
Volume 18, Issue 1 (5-2024)
Abstract
Pile design is subject to a number of uncertainties that must be addressed to ensure the reliability and safety of the foundation. A common approach to reduce uncertainties in pile design is to calibrate the resistance factor in the Load and Resistance Factor Design (LRFD) method through reliability analysis. However, it is important to recognize that the LRFD method may not fully account for uncertainties associated with soil and pile resistances. The results of this study show that the separate consideration of base and wave resistance can lead to a more accurate and reliable design of piles. The proposed method can help engineers make more informed decisions and reduce uncertainties in pile design. In addition, the study highlights the importance of considering different factors such as the ratio of dead to live load and the ratio of base to shaft resistance when calculating the resistance factor.
Amin Ahmadi, Maryam Zebarjad, Ghoramreza Mirzavand,
Volume 18, Issue 1 (5-2024)
Abstract
The zone of influence is the area where water withdrawal from the well causes the water level to fall. The drawdown cone is a conical shape of the water level in the zone of influence, and it is necessary to know the effect of the factors influencing it. Previous studies have mainly investigated aquifers with horizontal water levels and less realistic conditions. The purpose of this study is to investigate the effect of well physical parameters on the drawdown cone in one of the unconfined aquifers with a sloping water surface. In this aquifer, a normal discharge well was simulated using the Modflow program and the effect of the target parameters was studied. The results showed that: the drawdown cone is symmetrical up to long pumping and relatively long distances; the zone of influence will eventually extend to the entire aquifer and significant drawdown will occur at long distances. A significant part of the drawdown in the well is recovered in the first moments of pump shutdown, but at long distances, the drawdown continues to increase for a long time. An inflection point can be extracted from the drawdown cone which represents the minimum drawdown that does not increase after the pump is stopped and can be introduced as a unique value. By increasing the flow several times, the depth of the cone increases, but the width of the cone increases only slightly. If the pump is turned on and off successively, the general shape of the cone does not depend on the nominal discharge of the well, but mainly on the average discharge of the aquifer. Relative infiltration increases the depth of the cone only near the well and has no significant effect on its shape further away.
Mohammad Zainali, Dr Mohammad Reza Asef, Dr Ruholah Nadri,
Volume 18, Issue 1 (5-2024)
Abstract
This paper investigates the application of geomechanical and geological engineering methods to determine the optimum working face width for the safe and efficient extraction of manganese ore extraction at the Venarch Mine (Qom Province, Central part of Iran). The underground workings on the west face (240m depth) present significant geotechnical challenges due to the presence of faults, clay seams, and loose rock layers. These features require careful careful stability analysis to ensure the safety and economic viability of the underground mining operation. This study uses three established methods for rock mass classification and stability assessment. The Rock Mass Rating (RMR) classification system, the Q-system (Barton), and the numerical analysis using Plaxis 3D software. A robust and data-driven approach to determining the optimum workshop width was achieved by employing a synergistic combination of these three methods, together with meticulous ground observations and expert engineering judgement. This framework offers a powerful tool for determining the optimal and safe workshop width for this sector of the mine. By capitalizing on the strengths of each methodology, this research aims to establish a data-driven and informed decision-making process to ensure a stable and economically viable approach.
Somayeh Zarei Doudeji, Rahim Bagheri, Hadi Jafari,
Volume 18, Issue 1 (5-2024)
Abstract
Groundwater resources in Iran are of particular importance due to the lack of surface water resources, lack of precipitation, high evaporation volume and recent droughts. The first step in identifying and exploiting groundwater resources is its quantitative and qualitative investigation. Neyriz watershed, located in the study area of Qatroiye desert, has 17 piezometers, whose groundwater level has been recorded monthly during the statistical period of more than 12 years. Investigations of the groundwater level and the map of the flow lines show the anomaly of the flow in the south and southwest part of the aquifer, which shows the direction of the groundwater flow contrary to the direction of the topography of the area. In this research, an attempt was made to investigate the cause of this anomaly based on the available information, including piezometer drilling logs, aquifer quality data, and national statistical data. Based on the qualitative information of the aquifer, the electrical conductivity and chlorine values of the groundwater increase in the direction of the topographic slope, which indicates the flow in the direction of the topographic slope. Qualitative charts of Piper, Schuler and Durov also confirm this issue. The level of groundwater in selected exploitation wells for qualitative sampling based on the information of the depth of groundwater in national statistics also indicates the flow in the direction of the topographic slope. Finally, a clay layer with a thickness of 10 to 30 meters was observed in the drilling log of the piezometers in the south and southwest of the aquifer. Examining all the results shows that the existing aquifer is probably a double-layered aquifer, where the flow direction in the upper layer is in the direction of the topographic slope and in the lower layer is against it, and the piezometers of the south and southwest parts penetrated the lower aquifer. In order to confirm the desired hypothesis, it is suggested to carry out geophysical studies in the area or to dig exploratory wells.
Kamal Ganjalipour, Reza Azimi, Mojtaba Moradi,
Volume 18, Issue 1 (5-2024)
Abstract
In determining the water that can be allocated for different uses, including agriculture (as the main consumer), the most important step in this era is the proper management of groundwater resources. The observance of water consumption within the limit of allocated water ensures that the consequences of the exploitation of groundwater resources and the sustainability of development are guaranteed, and operators use technological methods to increase the efficiency of using water resources for more production in proportion to the amount tend to available water. In this article, first, the method of calculating the water allocated to the agricultural sector in the country has been studied and criticized. In this study, it was found that in the formula for calculating the current allocated water, the component of agricultural return water as an effective parameter causes a huge error in the calculation of allocated water. Then, a new formula for the calculation of allocated water was proposed, and an attempt was made to correct and apply the effect of the input component of agricultural return water on the amount of allocated water based on the calculation of allocated water in the new proposed method, taking into account the aquifer capacity based on the parameters of the water resources balance.
Ms Roghayeh Hasani, Dr Ebrahim Asghari-Kaljahi, Dr Sina Majidiana,
Volume 18, Issue 2 (9-2024)
Abstract
With the expansion of the petroleum industry and the aging of facilities and pipelines, oil spills are becoming more frequent. In addition to environmental impacts, oil spills can cause changes in the plasticity and dispersivity of soils. To investigate the potential for dispersion in fine-grained soils due to oil leakage, soil samples were collected from the Shazand Refinery area in Arak and mixed with 0, 5, 10, 15, and 20% by weight crude oil. Specimens were prepared at the maximum dry density obtained from the Proctor compaction test and, after curing, pinhole and double hydrometer tests were conducted. The results of the mentioned tests showed that the fine-grained soil tends to disperse with the addition of up to 15% oil, and this dispersion increases with further increases to 20%. Changes in the soil fabric with increasing oil content were investigated using scanning electron microscopy (SEM) images, and the results showed that the dispersion of soil particles increased with increasing oil content.
Seyyed Mahmoud Fatemi Aghda, Seyyed Sara Mousavi Herati, Mehdi Talkhablo, Amir Maziar Raeis Ghasemi,
Volume 18, Issue 2 (9-2024)
Abstract
The alkali-silica reaction of aggregates is one of the most significant factors in the destruction of concrete structures worldwide. This is due to chemical reactions between alkaline fluids in concrete voids and active silica minerals present in some aggregates. Considering that many physical, chemical and mechanical properties of concrete are related to aggregates, the role of aggregates in concrete is crucial. This research aims to investigate the compatibility of aggregate petrographic studies and accelerated prismatic mortar testing in predicting the reactivity of aggregates and determining the intensity of aggregate reactivity using the DRI index (a semi-quantitative complementary petrographic analysis). The study was carried out on laboratory samples of aggregates from mines around Tehran, using the ASTM C295, ASTM C1260 and ASTM C856-4 tests. The results showed that pyroclastic aggregates, which include sandy tuff, crystalline tuff (dacitic andesite) and glassy tuff, have the potential to cause an alkali-silica reaction due to their glassy background and microcrystalline silica. During the alkaline reaction tests of the aggregates, evidence of gel was found in cracks, holes and cement paste. In addition, the DRI index showed that the fine aggregates of both study areas were in the "slightly damaged" category and the coarse aggregates were in the "severely damaged" category.
Somayeh Zarei Doudeji, Rahim Bagheri, Hadi Jafari,
Volume 18, Issue 2 (9-2024)
Abstract
Due to Iran's weather conditions and lack of water resources, dam construction projects are particularly important for the country's development and progress. Water resources management based on system dynamics is capable of simulating complex water resources systems. This model for the simulation of water resources has various capabilities, such as increasing the speed of model development, the possibility of group development of the model, effective communication of the results, and increasing confidence in the model through user participation. In this research, the model of the dynamic system of the multipurpose dam of Qamshek in Hormozgan province has been simulated using the probabilistic simulation method. The purpose of this modelling is to realize different needs of the dam (domestic, environmental, industrial and agricultural) before its construction and to check the quality conditions of the reservoir. The study of the results of the quantitative modelling was done after calculating the annual and monthly percentage of volumetric and temporal supply of different needs and their source of supply. The results show that the volumetric supply percentage of domestic, environmental, industrial and agricultural needs of the dam is 95.53, 95.02, 94.18 and 93.14% respectively, and the temporal supply percentage of domestic, environmental, industrial and agricultural needs is 95.19, 94.94, 93.67 and 92.91% respectively, which are all within the acceptable range of the Ministry of Energy. Qualitative modelling of the dam was carried out for the most pessimistic case with a discharge electrical conductivity of 3000 and a base discharge of 10000 micromos/cm, on the basis of which the maximum electrical conductivity of the reservoir was calculated to be 11900 micromos/cm. Based on this research, it was found that by modelling based on model evaluation indicators, including percentage of volume supply and percentage of time supply of different needs, it is easy to quantify the effect of exploitation and management policies on the way of determination and allocation. Observed the quality of water resources and made the most optimal decision.
Dr Sepideh Shakour, Dr Manouchehr Chitsazan, Dr Seyed Yahya Mirzaee,
Volume 18, Issue 2 (9-2024)
Abstract
One of the appropriate ways to prevent groundwater pollution is to identify vulnerable aquifer areas. The Dezful-Andimeshk Plain has two landfills that do not comply with the necessary standards for waste disposal and a river that recharges the aquifer, which can be potential pollutants for the aquifer. Therefore, evaluating the pollution potential of this aquifer is considered a necessity. To achieve this goal, for the first time in this area, the assessment of the aquifer pollution potential was carried out based on the intrinsic vulnerability (DRASTIC) and specific vulnerability (DLR), and finally, the potential contamination (PC) in the region was evaluated.. Based on the results, the value of the inherent vulnerability index ranges from 106 to 162 and has two vulnerability classes: moderate and high. The high vulnerability is related to the western margin of the plain and near the outlet of the plain, as well as in the middle of the plain with a northeast-southwest trend. The low vulnerability is associated with the northern and southern parts of the region. The specific vulnerability index ranges from 25 to 75, which, based on expert opinion, is classified into two classes: low and medium vulnerability. The highest intrinsic vulnerability is in the middle of the plain and around the Dez River. According to the results, the aquifer's PC ranges from 130 to 207 due to specific and intrinsic vulnerabilities. It is classified into three classes: medium, high, and very high, mainly affected by the river, land use, soil, and hydraulic conductivity.
Dr Amir Saberinasr, Dr Majid Dashti Barmaki,
Volume 18, Issue 2 (9-2024)
Abstract
One of the strategies for water storage in arid and semi-arid areas such as Iran is the construction of underground dams; however, identifying suitable sites for the construction of these structures remains a major challenge. The aim of this paper is to identify the optimal locations for the construction of underground dams using a geographic information system and multi-criteria decision making techniques. Firstly, thematic maps were prepared in ArcGIS environment including geological condition, land use, landslide potential, topography, water stress, aquifer area and distance from dam, village, qanat, stream, fault, airport and road. Hierarchical analysis and fuzzy logic methods were used to weight the prepared maps. By removing unsuitable and restricted areas for the construction of underground dams, a final potential map for this structure was prepared. The results show that the provinces of Razavi and South Khorasan, Kerman, Yazd, Sistan and Baluchistan, Hamedan, Qazvin, Zanjan, Markazi and Qom have greater potential for the construction of underground dams than other provinces in the country. Finally, to validate the results, a comparison was made between the results presented in this study and several successful underground dam projects in the country, showing a relatively close match between the potential map and the implemented structures.
Prof. Hamid Reza Nassery, Eng. Maryam Arab, Dr. Zahra Kayhomayoon,
Volume 18, Issue 2 (9-2024)
Abstract
The study of the aquifer hydrogeochemical processes and the detailed investigation of the groundwater pollutants in order to control the pollution and prevent its environmental consequences are of special importance. The aim of this research is to investigate the effect of the Siahroud River on lead and nitrate contamination of groundwater in Qaimshahr-Joibar plain. For this purpose, two surface water samples were collected from Siahroud River, before and after Qaimshahr city, and 13 groundwater samples were collected from 13 wells, located in the bed of Siahroud river, in three periods during 2019-2020. The of nitrate, lead and dissolved oxygen concentrations of the samples were measured in the laboratory of Mazandaran Regional Water Company. The assessment of the pollution of water resources in the area shows that the discharge of urban, rural and industrial sewage and agricultural drains into the Siahroud River has caused an increase in the concentration of nitrate and lead ions in the groundwater. The Siahroud River has had an impact on groundwater pollution in the Qaimshahr plain in the upstream and some middle parts of the range due to the direction of groundwater flow and the exchange that exists between the river and the aquifer, as well as the direct discharge of pollutant sources to surface water.
Dr Mehran Esfahanizadeha, Dr Mohamad Davoodi, Dr Ebrahim Haghshenas, Dr Mohamad Kazem Jafari,
Volume 18, Issue 2 (9-2024)
Abstract
The determination ofgeological subsurface strata and shear wave velocity profiles is one of the most important engineering measures for seismic design and site effects studies. Recently, the use of seismic geophysical methods in engineering geological studies for this purpose has become widespread. In this paper, the accuracy and efficiency of seismic geophysical methods with active and passive seismic source in determining the subsurface geological structure of a selected site in the city of Abasabad in northern Iran have been studied. To this end, first, by conducting several exploratory boreholes, the subsurface geological structure of the study site up to a depth of 70 meters was carefully determined using engineering geological experiments. The results of this section showed that the shallow sediments of Abasabad site are mainly composed of sandy soils with four separate geological layers. In the next step, in two other separate boreholes, seismic geophysical experiments with active source of down-hole test were performed in order to accurately determine the shear wave velocity profile in different layers. In addition, in the next phase, using the array microtremor recording method, which is a new seismic geophysical method of passive-source type, to determine the subsurface geological structure of the study site in the form of shear wave velocity profiles. It should be noted that the array microtremor recording was performed using fifteen different arrangements of receptors (with different numbers and distances of receptors) and by two analyzing methods including F-K and SPAC. The results of these studies showed that both active and passive seismic geophysical methods had acceptable performance in determining the subsurface geological stratification of the site. It also could be inferred that the down-hole test with high accuracy determines the shear wave velocity in each layer compared to the array microtremor method but requires artificial production of seismic waves and borehole drilling. Array microtremor method without the need for drilling and production of artificial seismic waves has high efficiency in determining the subsurface layering and estimating the shear wave velocity of each layer and in general the results of this paper showed that in estimating the shear wave velocity compared to down-hole method shows up to 10% error.
Mr. Farhad Mollaei, Dr. Reza Mohebian, Dr. Ali Moradzadeh,
Volume 18, Issue 3 (12-2024)
Abstract
The brittlenessindex is one of the most important parameters in geomechanical analysis and modeling. Many methods have been proposed to estimate the brittleness index. One of the recently used methods is the intelligent method. In this paper, firstly the aim is to introduce a new algorithm using deep learning algorithms to predict the brittleness index in one of the wells of the hydrocarbon field in southwest Iran. In this article, first, the effective features for the input of the algorithms were determined using Pearson's correlation coefficient, and then using (recurrent neural network + multi-layer perceptron neural network) (LSTM + MLP) and (convolutional neural network + recurrent neural network) (CNN+ LSTM) brittleness index was estimated and the mean error value (MSE) and coefficient of determination (R2) were calculated for the training and test data. For both training and test data, both algorithms have a coefficient of determination close to 1 and a very low error. Also, in order to ensure the results of the algorithms, a part of the data was set aside as blind data, and the error and coefficient of determination were calculated for this data, and the error was MSE CNN+LSTM =26.0425, MSE LSTM+MLP =32.0751 and the coefficient of determination was R2 CNN+LSTM =0.8064, R2 LSTM+MLP =0.7615 . The results show the effectiveness of the introduced deep learning algorithms as a new method in predicting the brittleness index, and comparing the two algorithms presented, the CNN+LSTM algorithm has higher accuracy and less error.
Dr Masoud Amelsakhi,
Volume 18, Issue 3 (12-2024)
Abstract
Tunnels behave differently under seismic conditions due to their geometric shape, geotechnical parameters and installation depth. Although tunnels are less damaged compared to surface structures, they are still damaged during earthquakes. Various experiences have proved this matter, so researchers are concerned to study the seismic behavior of tunnels. In this research, circular tunnels are discussed under static and pseudo-static loading. In addition to different pseudo static earthquake factors, internal soil friction angle, soil behavior models, sliding and non-sliding of tunnel wall are also studied. Three different soft, medium and stiff soil conditions are studied. Some results show that in all three soil conditions and two soil behavior models, Mohr-Coulomb and hardening soil, the horizontal displacements increase due to the increase of the pseudo static earthquake factor. It should be noted that softening of the soil increases the horizontal displacements.
Zahra Aghayan, Rouzbeh Dabiri,
Volume 18, Issue 3 (12-2024)
Abstract
Recently, the demand for rapid and cost-effective infrastructure development has led to the has led to the development of various soil improvement techniques, including stabilization. Studies on the incorporation of mineral materials such as lime and coal ash into soil stabilization have been carried out in several countries, and these studies have shown promising results. Given the beneficial properties or properties of coal ash, together with its availability and cost-effectiveness, the combination of coal ash with lime for clay soil stabilization is a viable option. This study evaluates lime and coal ash on the behavior and geotechnical properties of clay soils. The evaluation includes plasticity index (PI), compaction, uniaxial compressive strength, California bearing ratio (CBR) and direct shear tests, and direct shear tests. To achieve this, the process began with the mixing of clay with varying percentages of hydrated lime (4%, 6% and 7%), followed by a 28-day curing period for the samples. Coal ash was then added at different (5%, 15%, 25% and 50%) was incorporated into the clay and also cured for 28 days. In the final stage, the optimum amount of hydrated lime was determined, an amount of hydrated lime, equivalent to the amount of coal ash used, was added to the clay and the mixture was cured for a further 28 days. The results indicate that A mixture of 7% hydrated lime and 50% coal ash, after 28 days of curing, is an optimum combination for stabilizing the clay in the study area. This combination increased the uniaxial compressive strength by 1.87 times, the shear strength by 1.34 times and the CBR value by 6.4 times, making it suitable for use in the for use in the construction of pavement layers.
Dr Sasan Motaghed, Dr Marzieh Shamsizadeh, Dr Nasrolla Eftekhari,
Volume 18, Issue 3 (12-2024)
Abstract
In this study, we present the Seismic Hazard Possibility Space (SHPS) for the city of Ahvaz. To achieve this, we applied the intuitionistic fuzzy method to weigh the logic tree used in the hazard analysis and constructed the SHPS based on expert opinions regarding the degrees of membership and non-membership. Hazard disaggregation was performed by through the concept of intuitionistic fuzzy sets, leading to the development of an intuitionistic fuzzy of an Intuitionistic Fuzzy Logic Tree (IFLT). The SHPS includes both the degree of membership and non-membership for pathways contributing to hazard generation. The SHPS illustrates the acceptance, non-acceptance, and ambiguity associated with potential hazard values from an expert perspective, thus assisting analysts in selecting appropriate hazard values. According to the numerical results of our analysis in the Ahvaz region, the seismic hazard is located in an uncertainty (unacceptability) zone, indicating that experts have low confidence in the results of the probabilistic seismic hazard analysis (PSHA) for Ahvaz. In addition, the hazard is characterized by an "unconfident zone". This finding indicates that experts are fairly confident in the results of the analysis for Ahvaz. This finding implies that the models and parameters used in the PSHA for this region are not accepted by experts, and further efforts are needed to identify or develop appropriate models and accurate parameters specific to the area. In conclusion, this research demonstrates how intuitionistic fuzzy sets can be used to construct SHPS, providing a novel framework for quantifying uncertainty and expert opinion in hazard assessment.
Shaghayegh Samiee-Rad, Giti Forghani, Hadi Jafari,
Volume 18, Issue 3 (12-2024)
Abstract
The Garmabdasht River as the first tributary of the Qarasu River, flows through the city of Gorgan and eventually flows into Gorgan Bay. In order to study the hydrochemistry and to assess the water quality, 10 water samples were collected in June 2022. Physicochemical properties (pH, electrical conductivity, total dissolved solids), major ion concentrations, and microbiological parameters (dissolved oxygen content, biological oxygen demand, chemical oxygen demand, and coliform bacteria) were measured by standard methods. The obtained results show that the pH of the water samples varies between 7.5 and 8.5 and the electrical conductivity of water samples varied between 376 and 665 µs/cm. In terms of hardness, water samples were classified as hard and very hard. The concentrations of the major ions, phosphate and nitrate were within the permissible range for drinking usage. By calculating the ionic ratios and drawing the Durov diagram, it was found that the water chemistry was mainly controlled by the dissolution process. The position of the samples on the Piper diagram shows that the type and facies of the river water samples were calcium bicarbonate, magnesium bicarbonate and calcium sulphate. According to the Wilcox diagram, the Garmabdasht river water was suitable for irrigation. The residual sodium carbonate and sodium percentage values confirm this conclusion; however, based on the magnesium hazard index, the studied samples were not suitable for irrigation. The values of dissolved oxygen in all samples were within the permissible limit. The amounts of biological oxygen demand and chemical oxygen demand in some stations exceeded the permissible limit due to the influx of livestock and agricultural effluents. The obtained results show that the samples were microbially polluted, which may induce the health problem in the local population. The values of NSFWQI also shows that, except for the upstream samples of S1 and S2, the quality of the studied samples for drinking is in the bad to medium class.
Dr Eisa Hajiradkouchak, Dr Behzad Rahnama, Dr Hasan Nasrollahzadeh, Mr Ali Shahbazi, Mr Reza Raeiji, Mr Kazem Babaei,
Volume 18, Issue 3 (12-2024)
Abstract
Many researchers believe that providing safe water, sanitary disposal and optimal management are the three axes of health, and in all these cases, while paying attention to the process of doing work, continuous control should also be done. This study was designed and implemented with the aim of seasonally investigating the physicochemical and microbial water quality of Qarasu River in Golestan province using the IRWQIsc index. 6 sampling stations were identified for Qarasu River and sampling was done once every month in four seasons of 1400. The measured parameters include pH, BOD, COD, dissolved oxygen (DO), electrical conductivity (EC), ammonium (NH4), nitrate (NO3), phosphate (PO4), total hardness (TH), turbidity and total suspended solids. It was a stool form. According to the measured parameters, Iran's surface water quality index IRWQISC was calculated. The results of the study based on the index showed that the quality of this index for all stations in all seasons was between 70.5 and 14.7 and according to the IRWQISC index, it was in five good categories (70-1.85), relatively good. (55-1/70), relatively bad (30-44-9), bad (15-29-9) and very bad (less than 15). The influencing parameters were total suspended solids, turbidity, nitrate, temperature and fecal coliform. It can be concluded that the amount of 70.5 with good quality is related to (Tuskestan village) in winter and the amount of 7.14 with very bad quality is related to (Pol Qara Tepe) in summer that the quality of the river water in The Gorgan to Aqqla road bridge station (Qorban Abad) is in bad condition in all seasons due to the entry of urban and industrial pollutants into this station, and Tuskestan village station has good and relatively good quality in most seasons because Tuskestan is in It is located in high altitudeand the entrance of clean running water into thisarea is more and it is far from industrial and urban pollutants.
Mr. Ehsan Pegah, Mr. Behrang Feiz Aghaei,
Volume 18, Issue 3 (12-2024)
Abstract
Random noise reduction has always been one of the most important issues in seismic data processing. This study investigates one of the most effective random noise reduction methods, the 2D multi-stage median filter. This filter is applied to seismic data by applying a series of 1D median filters in different directions and then selecting the output value corresponding to the center of the 2D window. By applying a 2D multi-stage median filter to both synthetic and real data, it is shown that the filter can effectively attenuate random spike-like noise in both pre-stack and post-stack data. Similarly, based on spectral analysis, it is shown that this filter does a good job of reducing the level of high frequency random noise in both synthetic and real data. In this study, a 2D median filter is applied to synthetic data containing random noise with a density of 10%. Since increasing the filter length can damage useful signals in addition to attenuating random noise, it is important to specify an appropriate filter length. For synthetic data, the error ratio plot shows that a filter length of 9 points is appropriate for the first stage. In the second stage, a 2D median filter with a length of 7 points was applied to the output of the first stage filter. The effect of this filter on random noise suppression can then be observed by spectral analysis. In addition, median filters of 7 points and 5 points were applied to the pre-stack and post-stack real data, respectively. The effect and efficiency of this filter is assessed by examining the resulting difference plots, sections and spectral analysis.
