JOURNAL OF THE EARTH
Year:2012 | Volume:7 | Issue:24|Papers Count:20

The seismicity and seismic hazard analysis studies of dam projects is highly necessary in order to better understanding of the geology and geotectonic of the site region. The results from the seismology can support and evaluate the obtained parameters in the region. This study deals with the pattern of seismicity and the seismic hazard analysis in the study region of the Alan dam site. For this purpose, after identification of potential sources and background of seismicity in the region, by seismic hazard analysis, the maximum values of ground motion parameters were calculated. This was done in order to control the dam design and the related structures for the seismic hazard assessment. The most important controlling parameter of motion that was determined by deterministic and probability methods. According to this studies strong ground motion for seismic hazard assessment, is the pick strong ground the ground motion acceleration of the Alan dame site is 0.3 g that is high in Iranian building standard.

In recent years, many industries activities such as refining crude oil, aluminum and zinc production, ship repair and construction, loading and unloading of minerals and chemicals, etc. As a development center in Bandar Abbas, southern Iran, which formed the subject exacerbate pollution load destruction of sensitive ecosystems coastal waters region. Therefore, measures to identify and measure heavy metals and trace elements with regard to harmful effects on marine ecosystems including aquatic and consequently affects puts man in sediments of coastal waters is an important. Based on this in this study the amount of heavy metals Zn, Mn, Co and Cd in sediments in coastal areas target Bandar Abbas apparatus flame atomic absorption spectroscopy was measured. All stages of sample and digestion of sediment according to standard methods (MOOPAM) was. Thus, the average concentration of heavy metals Zn, Mn, Co and Cd in sediments, respectively 89.1±0.3, 519.3±19.1, 36.4±3.9 and 2.1±0.2 (mg g-1) dry weight sediment, respectively. This values with an average concentration of elements in sediments above and other global internal and external areas were analyzed and compared. Statistical analysis (ANOVA: Single Factor) showed that the average concentration of heavy metals Zn, Mn, Co and Cd in sediment are significant differences between the crossings. Two elements Cd and Zn with a correlation coefficient of 0.575 have the highest correlation and then the order of elements Co and Mn with the coefficient correlation 0.5, Zn and Mn with the coefficient correlation 0.085, Co and Cd coefficient correlation 0.016, Zn and Co coefficient correlation0.01 and Mn and Cd with the coefficient correlation 0.002 are. With coefficient significant and positive correlation between Cd and Zn, Co and Cd, Zn and Co and finally be determined that the source of pollution in the sediments of these elements is the same. The results show there are no statistically significant correlation for Cd, Mn coefficient.

“Ardabil Plain” is a middle plain that is located in northern width with geographical charactristics of 38o, 04’ to 38o, 25’, and eastern length with geographical charactristics of 48o, 10’ to 48o, 37’. This plain with width of 900 kilometers with an average height of 1350 meters is surrounded by its elevated and high highlands. Great portion of the boundary which was studied is covered by Quaternary sediments (the new one and the old one), by Quaternary sediments consisting of gravel, sand, silt and clay that include the border and the center of this plain. As you move from east and south-east towards west and north- west the amount of coarse-grained alluviums and succulent decreases. In west and north-west the boundary of output of water is nominal and is not suitable for digging a well. According to results of the analysis on a sample of 35 deep well in the region in 14 phases of the time, it is observed that in eastern area, that is at enterance of aquifer the qualitity of water is suitable, but in south-west area because of vicinity with plaster components, existence of surface current and round washing and also mineral water springs (sulphate), the quality of water decreases and the type of water changed into clorine and sulphate. With respect to distribution of Schoeller more than 90% of samples are in good condition, concerning their being drinkable. According to categorization of Wilcox, more than 50% of the samples are related to class C1S1.

In the present work, we tried to find linear relations with suitable approximation for Maxwell functions needed for the examination of electromagnetic waves by simulation of a specified region. Then, by solving these functions, unknown functions such as distribution of electric and magnetic fields resulted from electromagnetic fields in two dimensional environments including bulk anomalies are prone to be solved. For these modeling, an environment with specific dimensions and nature is needed. This environment is formed indexing regularly in two-dimensional modeling. In this media the distances between points and geometrical structure are completely specified. Therefore, electric and magnetic vectors are the unknown quantities in all points of the lattice and their amounts are dependent to the geometry and nature of the environment. Different results could be deduced from these findings.FDTD method is used for solving the analytical equations. This method is used for solving analytical equations and calculating impedance in one- and two-dimensional situations. Moreover, Neumann and Drichlet absorbing boundary conditions were used to discuss electromagnetic field results in these boundaries. This numerical method led us to satisfactory results such as solving the problems existing in abnormal structures which are one of the most important problems in geophysical explorations. Time parameter and determination of linear or non-linear changes occurred in electromagnetic field in the frequency domain are another worry which is solved in our numerical method.Finally, the simulated results obtained from solving two-dimensional differential Maxwells and wave’s equations in homogeneous and abnormal environments by using FD method in one- and two-dimensions were recorded for each sample. Comparison of the results obtained from the two above method, revealed acceptable operation and good behavior of the simulated system.

According to safty of the important structures such as dams are vital. The Dorudzan dam is located in the seismotectonics province of Zagros. Due to high potential seismicity of the Zagros, design safety is vital. In this regard, we used deterministic and probabilistic approaches for earthquake hazard analysis. Moreover, the seismotectonic characteristicsof Zagros determined carefully. Earthquake-fault hazard, both by probablisticand and deterministic approaches were analyzed, and the PGA (maximum of vertical and horizontal accelerations) are presented. The results show low seismic hazard in the Dorudzan dam site based on data is presented in both ways.

A great number of engineering constructions are located on Asmari Formation, but unfortunately, geomechanical data gathered during the construction of these projects, is never used in future projects located on this formation. One of the objectives of the present paper is to find a new methodology to make it possible to use this huge amount of data, in order to decrease the cost and increase the efficiency of next geomechanical explorations. The other objective of this study is to evaluate the performance of Adaptive Neuro-Fuzzy Inference System in modeling and estimating of compressional and shear wave velocities. At first, the geomechanical laboratory tests results of the samples of 7 damsites located on this formation were gathered. Then, by means of statistical methods, appropriate independent variables and datasets were selected. At last, ANFIS method was employed to predict the compressional and shear wave velocities. The obtained results show that Adaptive Neuro-Fuzzy Inference System can be successfully used in estimation of wave velocities. Also, using the methodology presented in this paper, data gathered in former geomechanical explorations can be used in future ones, in order to optimize the exploration process.

Porosity is one of the most important parameters, which is considered as one of the fundamental factors in reservoir engineering. By knowing this parameter, specialists are able to design and manage, effectively, the process of oil and gas fields development.In this paper an attempt has been made to illustrate the seismic attribute of acoustic impedance, resulted of 3D seismic data by using the interpretation results of 3D seismic data and analysis of well logs.Due to validity of well data in the form of core sample or well logs data, only at the well point, we can extent reservoir properties in the whole field by using of 3D seismic data.

The study area is located in parts of Hormozgan Province. The Zendan-Minab zone in the transition zone between the zagros collision to the west and Makran subduction to the east.The orientation of the faults system is NNW-SSE. The Minab-Zendan fault system, consist of three approximately parallel faults with N160E trend (Minab, Zendan and Palami). In this paper it is tried by using Image processing techniques contrast enhancement increases and make the image more useful for processing. ETM+.The processing techniques which are used in this paper: contrast enhancement, composition of colors (RGB), filtering, principle component analysis, using the DEM images, Band Ratio, Fourier Transform, The optimum combination bands. Finally in this paper the ETM+ data was used from landsat 7 satellite.

Descriptions of reservoir parameters are necessary for recognition of hydrocarbon reservoir. According to this fact that the compressional waves data are more available than shear waves data, estimation of shear waves velocity from petrophysical data always is one of the serious challenge in hydrocarbon reservoir description. The significant parameters that affect waves velocity in carbonate rocks are porosity, porosity type, mineralogy, pressure, fluid saturation and temperature. In this paper by using hydraulic flow units based on experimental data, different rock types are studied and then relationship between shear waves velocity and compressional waves velocity is determined in each flow unit. The results represent acceptable match between shear waves velocity and compressional waves velocity in hydralical flow units, so that correlation coefficient in different hydraulic flow units are 0.89, 0.94, 0.84. whereas this coefficient for all samples is 0.58.

Metamorphosed and felsic and mafic plutonic rocks in the southeast of Ghorveh have wide range and located medial Sanandaj-Sirjan zone. Metamorphosed rocks in this region are regional and contact metamorphic type and plutonic rocks are granitoid and gabbroid. With intent of study of mineralogical of region rocks provided 110 thin sections overall existent rock that 45 thin sections are oriented. After performed petrographic studies on those rocks previously mentioned observed minerals such as andalusite, kyanite, sillimanite, garnet, biotite, chlorite, chloritiod, amphibole, calcite and opaque in the regional metamorphic complex, zoned garnet (andradite-grossularite), chlorite, epidote in contact metamorphism and quartz, alkali feldspar, plagioclase, muscovite, biotite, straurolite and opaque in felsic plutonic and olivine, pyroxene, biotite and plagioclase in mafic plutonic rocks. Existence different genesis and characteristics like undulatory extinction, sub and new grains in quartz, round and semi round shape in garnets, deformed twins in alkali feldspar and plagioclase indicate performed dynamic stresses during different deformation phases that change and/or generated them.

Investigating area is 38 Km far from Sabzevar Province and it is located in old roadway of Sabzevar-Neyshabour which is related to Mesozoic Ophiolites of Central Iran Mini Continent’s margin. Since there is no surface water in these regions, 22 water samples from ground water have been taken. In order to determine anions, cations, poisonous and heavy components, samples were sent to ICp-OES laboratory of applied research center of geology organization (Karaj branch).By examination of anions and cations, and drawing of Piper, Wilcox and Schoeller diagrams, it was clear that this area’s water is in the range of hard or very hard waters. Besides, they are mostly in the range of calcic, sodic and manizic bicarbonate water. From usage (drinking water) point of view, they are in intermediate level but from agricultural point of view, half of stations are in acceptable level and other half are not in the good condition. In addition, this region’s water also had NO3, Mg, Ca, … contaminations, that their thorough descriptions will be discussed in article.

Iran plate is prone to earthquake, occurrence of destructive earthquakes approximately every 5 years certify it. In this point of view, due to existence of happened great earthquakes and large number of potential seismic sources (active faults) which some of them are responsible for great earthquakes the North-West of Iran which is located in junction of Alborz and Zagros seismotectonic provinces (Mirzaii et al, 1998) is an interesting area for seismologists.Considering to population and existence of large cities like Tabriz, Ardabil and Orumiyeh which play crucial role in industry and economy of Iran, authors decided to focus on study of seismic hazard assessment in this area to achieve probability of earthquake occurrence and determine PGA in different parts of the mentioned area.It is important to note that however lots of studies have been done in North -West of Iran, but building codes modification needs more precisely seismic hazard analysis. Furthermore, previous studies have been applied free download software which were provided before 2000 but the most important advantage of this study is applying professional industrial software which has been written in 2009 and bought by authors. This applied software can cover previous software weak points very well such as griding potential sources, attention to the seismogenic zone and applying attenuation relationships directly.This study states the most PGA occurs in the area with NW to SE trend which fits very well with Tabriz fault strike. Also authors have applied different attenuation relationships and realized a number of them such as Boore-Atkinson (2003), although they are global, are not reliable in this region.

In this paper we are concerned with investigation and evaluation of environmental geology in North Tehran Fault zone, focusing on distribution of elements like Cobalt, Cadmium, Cupper, Lead, Zinc, Iron, Manganese, Arsenic and Silver. We used G.S.I data on these elements. Afterward, sampling was done, which was dispersedly and did not cover the whole region. The collected data then was processed using GIS software and presented as an isopach map.Then their relationship with lithology, faults, density of faults and drainage was investigated. We concluded that most of the concentration of elements is within Darband drainage basin. This is due to high density of North Tehran Fault and aboundance of joints and fractures along this fault, causing the diffusion of these elements to follow Eastern- Western trend of North Tehran Fault.

The area under investigation is located in the eastern part of the central Iranian microcontinent. By studying various structures such as faults and folds, the changes of tectonic regime from Cretaceous to Quaternary are studied. In this paper, attempts have been made, to understand the process of convergent and compression predominance to shear stress. The Cretaceous Ophiolitic rocks, Eocene-Oligocene volcanic rocks and Travertine deposits are outcropped. The remnants of sheared oceanic lithosphere, together with double plunge folds and strike-slip faults are suitable indicators to understand the change of tectonic regime in this region.

The area under investigation is situated between Tabas and Boushrouieh cities and it is including Tabas plain and Shotori mountain.In this research structural specification are introduced and geomorphic indices have measured there for Ereshk and Jamal faults have high and Shoutori and Ezmeighan faults have low relative tectonic activities on the other hand, seismicity of this area is consistable with measurements of geomorphic indices.

The purpose of this study is to detect structural fractures utilizing Landsat satellite data. Based on the regional fault-related morphologies, different techniques were utilized to detect fault lines and fractures. Several image (159-35, 159-36, 160-35, 160-36, 161-35, and 161-36) taken by Landsat ETM+images were used. The first method for detection of fault lines, lithological interruption and displacements due to faulting was the RGB technique and Grayscale images. In addition, to optimize the RGB composition, the OIF (Optimum Index Factor) formula was applied. In the next step, the resulting image merged with panchromatic band for increase the spatial resolution. The third utilized method was the NDVI technique, which was used to reconstruct the vegetation in studied region. The forth technique was applying Sunangel directional filters to detect sharp edges and fault lines. As the fifth method, the Digital Elevation Model (DEM) of under study region was shined with virtual sun light from different geographic directions using Sun-shading technique and the resulting image were used to detect linear fault-related valleys and ridges. In addition, Digital Elevation Model (DEM) was utilized to develop a 3D view of the region. The sixth method was the Principal Component Analysis (PCA), after which the PC1 was selected as the most suitable component for detecting fault lines. The seventh applied method was the Band Ratio technique, which was implemented in two steps. First, each fault line was detected separately in Grayscale images. Second, all fault lines were detected together in one RGB false color composite. Finally the Structural Map of Great Kavir fault was constructed using the fractures detected by the above mentioned techniques.