numerical modeling

This research examines and evaluates the nonlinear shallow water equations in the numerical modeling of tsunami waves. Tsunami modeling comprises three primary phases: the generation of tsunamis, their propagation across sea, and the final run-up upon reaching coastal regions. To evaluate the efficacy of the nonlinear shallow water model, an initial benchmark test was conducted. This test was pivotal in establishing the model's reliability, which then paved the way for simulating three significant historical tsunami events—the devastating 2004 Indian Ocean tsunami, the catastrophic 2011 tsunami in Japan, and the 1945 Makran tsunami. Laboratory data plays a crucial role in tuning and calibrating the numerical models, enabling them to better reflect real-world behaviors and outcomes. The results from these simulations showed a noteworthy alignment with actual historical data, showcasing an acceptable level of accuracy in the nonlinear shallow water numerical modeling approach. This compatibility was particularly pronounced for the 2011 Japan tsunami, where the availability of more contemporary and precise data supported more accurate modeling results. However, it is crucial to note that the observed discrepancies between the model outputs and the real-world scenarios cannot be entirely attributed to instrumental errors. Instead, a significant factor contributing to these discrepancies lies in the incomplete understanding of the underlying sources and mechanics of tsunami generation. Given this complexity, modeling tsunami generation carries a high level of uncertainty and represents a critical aspect of the modeling process. While the foundational equations governing water waves are well-established, there remains a pressing need for advancements in the modeling techniques utilized for tsunami propagation and run-up. Specifically, there is a strong imperative to refine the accuracy with which factors such as spray dynamics, friction with the seabed and coastal environments, and the multifaceted behavior of waves upon making landfall are incorporated into these models. These advancements have important effects beyond just research. They significantly impact tsunami risk assessment, early warning systems, and preparedness in coastal communities. Effective tsunami modeling not only enhances our understanding of these devastating natural phenomena but also fortifies our readiness to respond to future events. Given that tsunami modeling is a prerequisite for studying tsunami risk and developing warning systems in tsunami-prone areas, one essential requirement for accurate modeling is high-resolution bathymetric and topographic data. Furthermore, to better understand tsunamis, future studies must aim for a clearer picture of the geometry of tsunami sources, leading to more precise estimates of seabed deformation alongside conducting thorough geophysical, geological, remote sensing, and other field studies. The experiences from the 2004 Indian Ocean tsunami and the 2011 Japan tsunami demonstrate that utilizing tsunami early warning technology is crucial for providing timely alerts before the waves reach the shore, as there is no time to escape once the waves have arrived. In the two mentioned tsunamis, had a warning system been in place or functioning correctly, there would have been an appropriate opportunity to issue tsunami alerts from the source area to surrounding coastlines.

This article investigates the impact of sea level fluctuations on numerical modeling of groundwater behavior. The study employs GeoStudio, a finite element numerical model, to calibrate and validate the model using benchmark data from reliable sources. The investigation focuses on changes in saltwater levels under varying rates of increase and decrease. Results indicate that reducing saltwater levels in the numerical model does not affect the estimation of the final dimensions of the saltwater wedge. However, a sudden increase in saltwater levels results in an estimated wedge length that is 4% greater than gradual increases. Furthermore, the research reveals that the system reaches equilibrium fastest when water levels increase or decrease instantaneously. If the minimum time to reach equilibrium during a sudden decrease in water levels is denoted as TR_min, gradual changes in boundary conditions lasting less than half of this time do not impact the equilibrium time. The study also demonstrates that the time required to reach 50% of the advancing length of the saltwater wedge remains independent of the rate of change in saltwater boundary conditions. If the minimum time to reach equilibrium following an instantaneous increase in saltwater levels is denoted as TA_min, and the duration of saltwater level increase is equal to or greater than 1.4TA_min, the time to reach equilibrium of the wedge will be approximately the same as the duration of the saltwater level stabilization.

Deformation of microcontinents occurs during collision with a larger stable continent. Deformation is usually concentrated at the boundaries of the deforming microcontinent and depends on mechanical stratigraphy and pre-existing structures. The Alborz Mountains, located in the northern margin of central Iran underwent various deformations including Cimmerian, Laramide and Alpine compressions since the Triassic and its highest exhumation occurred in Cenozoic, as a result of the Alpine orogeny. Relocation of the Alborz Mountain front is visible in the satellite images in the Qazvin-Rasht area, where the geophysical maps also indicate changes in the basement at the subsurface. The aim of this study is to investigate possible factors responsible for this large displacement of the mountain front, using 2D numerical modeling. We designed and run five 2D models considering different parameters, such as the presence of basal and middle detachments and the effect of their thickness as well as the involvement of basement faults. The experiments show a faster movement of the deformation towards the foreland in the presence of basal detachment compared to the case without basal detachment. The addition of intermediate detachment intensifies this process. Increasing the thickness of the middle detachment increases the exhumation and deformation, especially towards the foreland. The model with a pre-existing basement fault shows very clear localization of deformation on the basement fault which causes developing the deformation towards the foreland. According to the cross sections constructed across the area on both sides of the change in the mountain front, there is an increase in the thickness of the Jurassic shale (Shemshak Formation) as a detachment level in the central Alborz, where higher exhumation and extensive outcrops of Paleozoic rocks is observed compared to the western Alborz. The numerical models with different thickness of intermediate detachments (1 and 2 km) have simulated this difference between the central and western Alborz. Considering the larger displacement of deformation front toward the foreland in the numerical model in the case of a pre-existing fault, the presence of a basement fault in the western Alborz could be assumed to cause the larger southward displacement of the mountain front compared to the central Alborz.

Increasing the depth of mining leads to placing the level of the mine pit in the area of mineral extraction below the groundwater level. The entry of groundwater into the mining pit increases the costs and also reduces the efficiency and safety level of the work. Gohar Zamin Iron Ore Mine with a reserve of approximately 600 million tons is one of the largest open-pit iron mines in the Middle East in the southwest of Sirjan city, located in Kerman province, which currently has a problem with groundwater entering the mine pit. In this research, MODFLOW software has been used in the complex environment of the Gohr Zamin Iron Ore Mine to model and predict the movement of underground water and the proper management of the drainage process. Due to the heterogeneity of the underground layers, which causes many changes in the hydrodynamic parameters in each place, an innovative Pilot Point network has been used to interpolate the value of the hydrodynamic parameters required by the model. After the calibration and validation of the model, the direction of the groundwater flow in the studied area is from the north side of the pit to the west. The amount of inflow water from the northern part of the pit and the outgoing water from the western part of the pit is about 679 and 1448 cubic meters per day, respectively. In the end, by performing optimization by the model, the position of seven new wells and the optimal pumped flow rate for existing and new wells in a proposed drainage scenario was determined. The prediction results of the model show a decrease in water level by 14 meters in the northern part and 10 meters in the eastern part of the studied area within one month.

One of the most important issues in urban areas is the stabilization of vertical and sloping earth walls. Nailing technique used for slope stabilization, has become popular day by day in urban environments, around the world.  Normal drilling wells, even at shallow depths, have collapsed many times when subjected to applied loads, resulting in reduced work progress, loss of life and unpredictable economic costs. On the other hand, the collapse of drilling holes causes to loosen the soil structure and reduce its density, which in turn causes more horizontal and vertical deformations to occur in the earth’s surface. This research, introduces the deep excavation stabilization with the aid of laboratory and numerical modeling and presents the effect of overburden and soil density on the nails behavior. It was observed that under the conditions of the same soil density, the pullout capacity of all types of nails increases with the increase of the overburden pressure applied on the soil. For example, by increasing the overburden from 0.2 to 0.5 kg/cm2, in a soil sample with a specific weight of 1.4 gram/cm3, it causes a 100% increase, and in a soil sample with a specific weight of 1.6 gram/cm3 causes a 150% increase in the nail pullout capacity. Also, under the same conditions of the applied overburden pressure, the pullout capacity of the nails will increase due to the increase in the specific dry weight of the soil, which is an increase in the density of the soil. In other words, by increasing the specific dry weight of the soil from 1.4 to 1.6 gram/cm3, by applying overburden of 0.2, 0.5, and 0.8 kg/cm2, the pullout capacity of the nail increases by 16, 35, and 40 percent compared to the initial state.

The aim of this study is to simulate stress variations and deformation of the continental plate in the subduction process. The main concept considered is that trench retreat during the subduction process can lead to the creation of an extensional stress regime in the overriding continental plate, and subsequent extension tectonics, and the thinning of the continental crust. The Iranian plate experienced distributed extension in the Eocene. One of the scenarios regarding this event considers the roll-back of the Neo-Tethys slab at that time as the cause of the extensional stress regime. Through numerical simulations to solve the conservation equations governing the flow and deformation in the crust and mantle, the role of rheology, thickness and age of the continental plate in the above-mentioned developments have been investigated. The results show that trench retreat can occur for a large range of physical parameters. Prolonged trench retreat can lead to a localized extensional tectonic regime near the edge of the continental plate above the subduction zone, 7 to 12 million years after the initiation of subduction. For a lithosphere with strong rheology, this tectonic regime results in negligible thinning, too small to be observable in the geological record. In contrast, for weaker continental plate, as well as a thin lithosphere, a wide-range of extensional deformations can occur, some of them comparable in terms of amplitude and time-scale with the events of the Eocene in central Iran.

The Caspian Sea is the greatest lake in the world. This basin plays a significant role in the climate of the countries located in the vicinity of it. This water body is divided into three basins, including the northern, middle, and southern parts. The Iranian coasts are located in the southern part. This paper uses the ROMS model to investigate the seasonal changes in physical oceanography phenomena in the Southern Caspian Sea. To deal with this, the model was run for seven years. The GEBCO data are utilized to make the grid file with the resolution of 30 seconds. Three-hourly ECMWF (ERA Interim) data was applied to the model. Furthermore, the Kura and the Sepidrud rivers were considered for simulation. The climatology and initial conditions data were extracted from World Ocean Atlas 2013 and ICOADS, respectively. In this research, the horizontal resolution of 2.5 km and 16 layers in vertical grids were applied to the model. The model outputs are validated with observation data and other simulations in this basin. The results show that the ROMS can be an appropriate model for simulation in this region, particularly in the southern part, as the outputs are compatible with the observation data. Moreover, the results indicate that the seasonal changes of temperature are remarkable compared to salinity.     While the model has recorded the mean value of 16°-18° C for temperature, this value for salinity is 13.5 PSU. The typical surface currents are counter-clockwise as the dominant winds are from the north to the south towards the Iranian coasts. The topography of the southern part controls these currents because most eddies are formed in the vicinity of the deep part of the south part. Some eddies are dipoles that can be observable in most seasons. The strongest eddies are formed in this basin in the fall, particularly in December. The most important finding of this research can be the fluctuation of the surface water, which varies from 5 to 10 cm, due to these cyclonic and anticyclonic eddies. When eddies are cyclonic, they form the center of cold water. This water mass can be 0.5°-1° C colder than the surrounded water. Herein, we conclude that these eddies can have two considerable effects on sea surface temperature distributions and sea surface height. Thus, this model shows the behaviors of eddies correctly. It should be noted that eddies can play a significant role in the propagation of oil spills in the southern parts, which is discussed in this paper.

Unsystematic execution of blasting process may result in serious damages. Blasting is a very complex process and almost all of blast designs are made based on empirical relations resulting from trial and error. In recent decades, considerable development of numerical methods has been made possible to achieve high accuracy study of blast effects on surface and subsurface structures. Among these methods are boundary element method, finite difference method and finite element method. It should be mentioned that there is currently no software which might be able to completely simulate blast process. But the UDEC software is able to simulate different aspects of this phenomenon through simplification and focusing on each aspect.  Therefore, the UDEC software was selected. In the present study, the modeling  has been performed for Ghareh Changool ramp of Zehabad Zinc and Lead Mine against blast loads.

Zehabad Ore deposit is located around 2 km south of  Zehabad Village of Tarom Sofla County, 56 km to northwest of Qazvin at 49˚ 25' east longitude and 36˚ 28' north latitude.
The formation surrounding the ore deposit is generally made up of pyroclastics, lavas and sedimentary rocks of Eocene age (Karaj Formation) which have been divided into 22 stratigraphic units. Lithological composition of the tuff units are often rhyolithic to dacitic and the lava units are consisted of rhyolite, dacite and andesite.
To  accomplish this study, we took rock blocks from Ghareh Changool ramp. Then, the blocks were cored in the laboratory to provide cylindrical samples for doing uniaxial compressive, triaxial, Brazilian and direct shear tests. Physical and mechanical properties of the tuff samples were determined according to ISRM standards. 
In the present study, field studies were done to calculate strength parameters and properties of the joints.  Based on these studies, three major joint sets were determined. In order to obtain the shear strength parameters of the joints, the cylindrical samples of andesitic tuff were molded by concrete and direct shear test was done on all of the joints according to ASTM D 4554.

To simulate the complex conditions of blast process, we used the discrete element software of UDEC for numerical modeling considering the discontinuity of the medium. To do a dynamic analysis, first the model should come to equilibrium in the static state. The space considered to be modeled in the study was a horse-shoe-shaped ramp with 4 m base, 4 m height and 1.5 m arc radius which was located in rocky medium consisting of tuff.  The height of overburden above the roof of the ramp was about 190 m. The dimensions of the model in UDEC was 20*20 m2. The behavioral model considered for the rock blocks and discontinuities were the elastic isotropic and surface contact of the joint (elasto-plastic) associated with Coulomb sliding failure, respectively. After defining the absorbing boundary conditions, the dynamic loads were applied to the model based on the defined time period. In mines stability and blasting process, the dynamic load resulting from the blast is often applied to a model as a pulse. By application of dynamic load and considering the other mentioned variations with respect of static analysis, the dynamic response of underground space could be estimated under vibration load of blast or earthquake. To do this, the blast impact wave was applied to the left side of the model as exponential pulse with maximum pressure of 4.41 MPa and time width of 0.7 to 7 msec. The results of the numerical modeling in static analysis indicated that no block would fall (Fig. 1). After application of the blast load, the results showed that there was no falling around the ramp (Fig. 2).

1. In static condition, after initial equilibrium no block was fallen into the ramp, regarding the blocks’ magnification plots, as a result the ramp was stable in the static loading.
2. In dynamic loading case, considering the displacement plots  around the ramp and the low values of these displacements, as well as, magnification plot of  the blocks 40 msec after the blast it can be said that no block was fallen into the ramp. Therefore the ramp was stable in the dynamic loading case and there was no need to install support system. .

The rapid increase in the water demand has led to large-scale groundwater developments in Ardabil plain, and intense extraction of groundwater has caused water table to decline as much as 12 m during the past 25 years. Optimizing the groundwater extraction in order to prevent declination of the water table and the possible compensation of the reduction in the aquifer storage are the main purposes of this dissertation. In this study, according to the modeling protocol, at first the conceptual model of Ardabil plain aquifer has been designed. For this purpose, a geodatabase consist of qualitative and quantitative data has been created. Then Kriging and fuzzy logic methods have been applied to create different kinds of zoning maps. After determining of the aquifer geometry, input and output parameters, groundwater flow system and hydraulic parameters, Modflow 2005 code was used by the PMWIN8 software for modeling the groundwater flow in Ardabil plain aquifer. After the modeling, based on the declination of the water table, the Ardabil plain aquifer has been divided to 15 zones. Then, the optimized values of the permissible extraction have been estimated using the PEST software. Based on the obtained results to balance the water table of Ardabil aquifer, the highest and the least exploitation should be at the east and center of the plain respectively.

Despite the ambiguous tsunamigenic behavior of the Makran Subduction Zone (MSZ), due to the low level of offshore seismicity, historical evidences and the 1945 tsunami in Makran confirm the potential of the MSZ for generating tsunami events. Possible future tsunamis generated by the MSZ will pose the coastlines of Iran to hazard more than any other country. Probabilistic tsunami hazard assessment (PTHA) is an effective approach to assess hazard from tsunamis and help for planning for the future. In this study, we assess the probabilistic tsunami hazard along the southeastern coast of Iran considering the entire Makran, the western Makran and the eastern Makran tsunamigenic sources. Tsunami scenarios include earthquakes of magnitudes between 7.5-8.9 for the western and eastern Makran and between 7.5-9.1 for the entire Makran. Both seismicity and tsunami numerical simulation are inputs for probabilistic hazard analysis. Assuming that the tsunami sources are capable of generating tsunamigenic earthquakes, estimating the annual rate of these events is required for PTHA. The truncated Gutenberg-Richter relation (Cosentino et al., 1977 and Weichert, 1980) is used in this study to compute the annual number of the earthquakes. We model tsunamis using the COMCOT well-known algorithm (Liu et al., 1998). The distributions of tsunami heights along the coastline of Iran are used in probabilistic tsunami hazard assessment. The results of PTHA show that Konarak and Sirik coastlines are posed to the most and least hazard from tsunamis, respectively. The probability of exceeding (POE) 1 and 3 meters increases with time. The probability that tsunami wave height exceeds 3 meters in 500 years is about 0.63 and 0 near the coastlines of Konarak and Sirik, respectively. The maximum POE for 3 meters belongs to the area between Beris and the west of Kereti. Distributions of probabilistic tsunami height along the coastline of Iran also indicate that Konarak and Sirik are the most and least vulnerable shorelines to tsunami hazard, respectively. The annual probability of exceeding 1, 2 and 3 meters are 1, 0.4 and 0.2, respectively. The results indicate the need of attention to tsunami long-term hazard along the southeastern coast of Iran, especially for the area between Jask and Beris. Our tsunami hazard assessment does not involve the tsunami inundation distances on dry land due to lack of high resolution site-specific bathymetric/topographic maps. Such computations are required in order to estimate the exact impacts of possible future tsunamis on the southeastern coast of Iran. High-resolution hydrographic surveys are required to be done in future for the major ports. Furthermore, future works should consider other possible near-field tsunami sources, such as the Murray Ridge, Minab-Zendan and Sonne faults and far-field tsunami sources, such as the Sumatra-Andaman subduction zone.

The central part of Fars province of the Zagros fold – thrust belt has complex geological structure and geometry probably due to activity of major basement strike slip faults. In this research numerical modelling were used considering different scenarios of the possible roles of Sarvestan, Sabz-Pushan and Nezam-Abad faults for strain distribution modelling. Models were constructed using FEM method and Mathematica software applying local convergence direction of Iranian and Arabian plates in the Fars area and different scenarios of presence of each of three faults. Results revealed vital role of the Nezam-Abad fault in coeval activity of Sarvestan and Sabz-Pushan faults at the time in forming of the geometry of the study area.

Recently, several studies on buried pipelines have been conducted to determine their uplift behavior as a function of burial depth, type of soil, and degree of compaction, using mathematical, numerical and experimental modeling.
One of the geosynthetics applications is the construction of a reinforced soil foundation to increase the bearing capacity of shallow spread footings. Recently, a new reinforcement element to improve the bearing capacity of soils has been introduced and numerically studied by Hatef et al. The main idea behind the new system is adding anchors to ordinary geogrid. This system has been named as Grid-Anchor (it is not a trade name yet). In this system, a foundation that is supported by the soil reinforced with Grid-Anchor is used; the anchors are made from 10×10×10 mm cubic elements. The obtained results indicate that the Grid-Anchor system of reinforcing can increase the bearing capacity 2.74 times greater than that for ordinary geogrid and 4.43 times greater than for non-reinforced sand.

Ground-penetrating radar (GPR) is a popular geophysical method for high-resolution imaging of the shallow subsurface structures. Numerical modeling of radar waves plays a significant role in interpretation, processing, and imaging of GPR data. A number of different approaches have been presented for the numerical modeling of GPR data. The most common approach for GPR modeling is the finite-difference method (FDM) because the FDM approach is conceptually simple and easy to program. The difficulties in applying boundary conditions at non-linear boundaries and the lack of sufficient accuracy in complex geometries are the most important drawbacks of FDM.
This paper presents a finite-element method, for simulation of ground-penetrating radar (GPR) in two dimensions in the time-domain. FEM is a powerful and versatile numerical technique for handling problems involving complex geometries and inhomogeneous media. The technique is based on a weak formulation of Maxwell’s equations. In the FEM method, the wavefield is discretized on the elements using Lagrange interpolation, and integration over an element is accomplished based upon the Gaussian-quad integration rule. The major difference between the various numerical methods is in the spatial discretization. In the elemental-based methods, the complex geometry of the problem is divided into several smaller and simpler elements, then the integrals are calculated for each element. These methods have no with any regular or irregular geometry. The responses of the model in the finite-element methods are approximated in nodal points, so nodal polynomials of Lagrange are used for interpolation of the model response. Besides, the systematic generality of the method makes it possible to construct general-purpose computer programs for solving a wide range of problems. In this paper, at first, Maxwell’s equations are discretized, then the boundary condition is applied to minimize artificial reflections from the edges of the computation domain. Although the governing equations and mechanisms are completely different between radar and seismic waves, most of GPR data processing approaches are derived from seismic data processing. Due to similarities in these two techniques, accordingly, we implement the first-order Clayton and Engquist absorbing boundary conditions (firstorder CE-ABC) introduced in the numerical finite-difference modeling of seismic wave propagation. This boundary condition is simple to apply. The presented formulations are in matrix notation that simplifies the implementation of the relations in computer programs, especially in MATLAB application. After spatial discretization with FEM, time discretization is done by Finite-Central Difference (FCD). The time discretization is the most massive and time-consuming step in modeling, which spatial discretization has an important role in this process. The stiffness, mass and damping matrices are sparse and symmetrical in FEM; so if we use the optimized numerical algorithms and storages strategies, computational costs and processing-time can be reduced significantly. To investigate the efficiency of FEM, the computer program has been written in MATLAB and has been tested on two models. The results show that the radar wave simulation via FEM is an accurate and effective approach in complex models.

Extended Abstract (Paper pages 247-276) Introduction Construction of highways and high weight structures on compressible soft soils requires planning and sufficient knowledge of geotechnical conditions of the site. Before construction of the desired structure on this type of soils, it is unavoidable to improve and modify these soils to prevent large unpredictable settlements resulting in damages to the structure. “Preloading” is a method widely used in soil improvement that dates back to 1930s and earlier. It is a simple and economic method of increasing the strength parameters of saturated fine-grained soft soils. Easy implementation, monitoring and measuring the settlement of ground using instrumentation and checking the behavior of this method during the procedure are among the advantages of this method. Preloading approach can be applied using radial drainage to enhance consolidation settlement rate, and without radial drainage by either embankment or vacuum. In general, soft clayey soils require a long time for settlement consolidation due to their low permeability. To increase the consolidation rate in these soils, radial drains are installed beneath the soil. These drains cause artificial drainage paths under clay soils that increase the rate of consolidation process by curtailing the drainage path, which in turn will rapidly increase the strength of soil, increasing the capacity of bearing new load on soil. In this regard, in order to improve subsurface soft saturated clayey layers under the oil storage tanks in Mahshahr project, the preloading method by embankment along with prefabricated vertical drains (PVDs) with a triangular pattern has been used, which has been assessed in this paper as a case study. Considering the different layers of soil and subsurface conditions in project site of Mahshahr oil depot and compressible layers located in relatively large depths, the improvement extent has been high to modify soil characteristics in order to avoid soil settlement and failure due to application of high loads from tanks. Inaccuracy of embankment settlement estimates and the prolonged preloading operations are among the challenges of soil improvement using preloading. Therefore, the proper selection of soil parameters including effective parameters in consolidation settlement values (Cs, Cc and Pc) and soil consolidation time (Kh and Kv) can address preloading as a viable and practical option for soil improvement. In this paper, back-analysis results of instrumentation data have been compared using Settle 3D software, and the initial effective geotechnical parameters obtained from laboratory and field experiments have been modified using this method. Using the modified results of this study can lead us to successfully evaluate and control the design of the mentioned project. Material and Methods In order to perform numerical modeling, the Settle 3D software based on Finite Difference Method has been used. This software was used to examine consolidation settlement according to consolidation theory formulations. For three-dimensional modeling of embankments, dimensions of both sides of the embankment must be set so that the actual ground conditions are considered with the least impact on general behavior of the model. The embenkment heights of EM-2B and EM-3 are 14.6m and 13.9m, respectively. In order to determine the boundary conditions, three times the base of embankment is considered from both sides of the model, and for the height of geotechnical region influenced by creation of embankment, which has been modeled in the program, a height equivalent to 5 times the height of embankment has been considered based on boreholes data. The Figure 1 shows numerical modeling of EM-2B and EM-3 embankments in the Settle 3D. In this software, degree of consolidation can be changed by placing drains in soil. In EM-2B and EM-3 embankments, in accordance with preloading operations of Mahshahr oil depot project, the length of drain was set at 25 and 22m, respectively, and drain spacing in each embankment was 1.5m with triangular configuration. Hence, after numerical studies and back-analysis, the value of Cf (permeability ratio of site to laboratory) reaches 9 in Settle 3D software. In addition, (Cc) and (Pc) are modified with with 0.14 and 190 kPa values in the software, respectively. Finally, the modified soil parameters are presented in Tables 1 and 2 for EM-3 and EM-2B, respectively. Table 1. Back-analysis results of consolidation parameters of EM-3 Kh (ML) (m/day) Kv (ML) (m/day) Kh (CL-2) (m/day) Kv (CL-2) (m/day) Cf (ML) Cf (CL-2) Cc (ML) Cc (CL-1) Settle 3D (After Preloading) 0.146 0.073 0.036 0.018 17 21 0.16 0.08 Initial Design Parameters (Before Preloading) 0.00864 0.00432 0.00172 0.00086 ….. ….. 0.17 0.17 Table 2. Back-analysis results of consolidation parameters of EM-2B Kh (CL-2) (m/day) Kv (CL-2) (m/day) Cf (CL-2) Cc (CL-1) Pc (CL-1-1) (kPa) Settle 3D (After Preloading) 0.0234 0.0117 9 0.14 190 Initial Design Parameters (Before Preloading) 0.0026 0.0013 ….. 0.17 180 According to the initial designs, for example, recorded value of settlement in the center of EM-2B settlement is approximately 122.2cm, while the settlement calculated in the center of EM-2B embankment has been 132cm. Therefore, initial values of calculated settlement based on assumed parameters was higher than the measured values of settlement. Lower values of measured settlements relative to calculated settlements can be attributed to conservative determination of geotechnical parameters and settlement equations based on one-dimensional theory of Terzaghi. Besides, parametric studies have been performed on the spacing and depth of vertical drains. Lastly, soil settlement induced by oil tanks has been compared before and after preloading based on modified soil parameters. Conclusion In this paper, the numerical modeling of soil consolidation has been discussed using pre-loading method with radial drainages in Mahshahr oil depot as a case study. In this regard, back-analysis using instrumentation results was conducted by Settle 3D software based on finite difference method, and the results were compared with each other. The basic geotechnical parameters obtained by laboratory and field experiments have been modified using mention method. The results obtained from the analysis indicate that settlement values from the instruments data were less than those back-analysis results. Indeed, the effective laboratory parameters intended for primary calculations of consolidation settlement values of the soil (Cc and Pc) were more and less than the actual measured values, respectively, and the effective laboratory parameters intended for time of soil consolidation calculations (Kh and Kv) were lower than the actual measured values. Also, parametric studies have been conducted on the spacing and depth of vertical drains. Finally, soil settlement indued by oil tanks was compared before and after preloading, and it was found that using this method for soil improvement can be very efficient in large-scale projects.

This study evaluates the performance of Earth system models for accurately simulating the phytoplankton productivity and bloom dynamics in the Oman Sea and the northwest of Arabian Sea. Satellite data (SeaWIFS ocean color) show two climatological blooms in this region, a wintertime bloom peaking in February and a summertime bloom peaking in September. On a regional scale, interannual variability of the wintertime bloom is dominated by cyclonic eddies which vary in location from year to year. During the wintertime, while both cooling in the winter and eddies control the blooms, variability in bloom location will arise from variability in the location of eddies, and so may not be predictable. In contrast, during the Southwest Monsoon, the dominant upwelling associated with the intense environmental forcing supersedes the effects of eddies, and the activity of the cold eddies is not pronounced. We consider numerical results from five different 3-D global Earth system models, which are denoted by CORE-TOPAZ, Coupled-TOPAZ, Coupled-BLING, Coupled-miniBLING, and the Geophysical Fluid Dynamics Laboratory (GFDL) Climate Model version 2.6 (CM2.6 miniBLING). Two coarse (1° grid resolution) models with a relatively complex biogeochemistry (TOPAZ: Tracers of Ocean Productivity with Allometric Zooplankton) capture the annual cycle but fail to capture both the eddies and the interannual variability. The results showed that the models differ from the observational data in terms of interannual variability. The low-resolution models (CORE- and coupled-TOPAZ) provide an almost uniform seasonal coefficient of variation, while both the data and eddy resolving CM2.6 models show higher interannual variability and seasonal changes. The coefficients of variabilities are particularly higher during the winter and summer blooms in the observations, while the low-resolution models do not see these signals. In other words, the low-resolution models fail to attain enough variability, while the high-resolution models (i.e. CM2.6) produce too much interannual variability. Accordingly, eddies are necessary to explain the variability in the data as opposed to the low-resolution models, but that the high-resolution model does not properly capture this variability. An eddy-resolving model (GFDL CM2.6) with a simpler biogeochemistry (miniBLING) displays larger interannual variability, but overestimates the wintertime bloom and captures eddy-bloom coupling in the south but not in the north. The models fail to capture both the magnitude of the wintertime bloom and its modulation by the eddies in part because of their failure to capture the observed sharp thermocline/nutricline in this region. In the wintertime, this leads to the excessive convective supply of nutrients and too strong of a bloom. However, for a few cases, eddies with blooms at the center are tracked in the southern part of the domain. For the model to simulate the observed wintertime blooms within cyclones, it will be necessary to represent this relatively unusual nutrient structure as well as the cyclonic or cold eddies. Both the temperature and mixed layer biases in the northern part of the Arabian Sea may result from having too much water from the Persian Gulf in this region. This is a challenge in the northern Arabian Sea as it requires capturing the details of the outflow from the Persian Gulf, something that is poorly done in global models.

Summary The Strait of Hormuz is a narrow waterway, which restricts water exchange between the Persian Gulf with the Gulf of Oman. This strait is exposed to inflow of Indian Ocean surface water and outflow of saline bottom water formed in the Persian Gulf. This water exchange leads to magnetic anomaly, which affects the
measured geo-magnetic field. In this research work, first, the marine currents in the Strait of Hormuz have been simulated using MIKE21 numerical model. Then, using extracted currents and appropriate relations the induced magnetic field due to marine currents has been calculated. The results show the space and temporal variability of current induced magnetic field in the study region. According to the study results, the maximum amount of vertical component of magnetic field in the study region varies between 0 to137 nT, while this amount for horizontal component of magnetic field varies between 0 to 153 nT.
Introduction Todays the applications of marine geo-magnetic field have been increased in several fields such as marine navigation, subsurface detection, etc. These applications cause to focus on the natural factors, which have direct impacts on marine geo-magnetic field. Among these natural factors, ocean or marine currents play a specific role on electromagnetic induction, and thus, influence ocean induced magnetic field, because of high electrical conductivity of marine waters and the dynamic impact of ocean currents. In the Iranian water, the Strait of Hormuz plays an important role on the magnetic field due to marine currents because of its complex regime of currents and its specific location. Therefore, this region has been selected for this study.
Methodology and Approaches In this research, the bathymetry map of study region has been obtained from GEBCO Database. Then, grid generation and interpolation of these data have been carried out using the mesh generation subroutine of MIKE21-MIKE ZERO software package. This mesh has been produced for introducing of geometry and bathymetry problems and includes irregular triangle elements. The final mesh, which has been used in this model, includes 49819 elements and 27915 nodes. In the produced model of the region, there are two open water boundaries at west and east of the Strait of Hormuz and two dry boundaries at south and north of the Strait. The required information for these boundaries has been forced to the model in the form of a data file, in which the data varies with time and space along the boundaries. The boundaries information is in format of P and Q parameters, which introduce the eastward and northward components of flow. After implementation of the model, for calculating the components of current induced magnetic field we use the model output data of flow and related formulation between components of magnetic field and components of flow.
Results and Conclusions According to the study results, the maximum amount of vertical component of magnetic field in the study region varies between 0 to137 nT, while this amount for horizontal component of magnetic field varies between 0 to 153 nT. In general, we can conclude that two factors of surface currents velocity and subsurface volume flow rate are the major factors influencing the magnetic field oscillations in the study region.