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8th Congress of the Balkan Geophysical Society
- Conference date: October 5-8, 2015
- Location: Chania, Greece
- Published: 05 October 2015
1 - 100 of 124 results
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Refraction and Amplitude Tomography Based Methodologies on Evaluation of Engineering Properties of Rocks - A Case Study
Authors A.E. Babacan and K. GelisliSummaryThe main aim of this study was the reveal of internal structures and engineering properties of basalt bedrock aged Eocene-Neocene, north of Eastern Pontides, Turkey. In selected area for this purpose, the seismic data were collected at total 7 profiles. A shallow refraction and amplitude attenuation tomography survey in study area was performed to mapping of Vp velocities and attenuation coefficient for civil engineering plans. In order to determine shear wave velocity (Vs) of study area, multichannel analysis of surface wave (MASW) in was also used. The Evaluation results show that the study area has three layers. The upper layer was interpreted as topsoil having a P velocity range from 400 to 800 m/s. The middle layer was interpreted as weathering basalt having a wave velocity range from 1200 to 1600 m/s. The bedrock was interpreted as massive basalt. P-wave seismic velocities of this bedrock range from 1800 to 2800 m/s. The average Vs 30 velocity was found 730 m/s from MASW. Attenuation coefficient is an important parameter to identification rock mass structure and 1/α value of weathering and massive basalt was changed between 5 and 15. During site selection, it has to determine to engineering properties of foundation rock.
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A Rapid Mapping of Sarıçiçek Pluton from In-situ Gamma Ray Measurements
Authors S. Altundas and H. ÇinarSummaryThe concentrations of equivalent eU, eTh, K% and dose rate values were measured using in-situ gamma-ray survey in order to map rapidly the surface geology of the Sarıçiçek pluton and its surrounding area. Gamma-ray spectrometric data were collected with a 512-channel portable gamma-ray spectrometer (NaI (Tl) cyrstal) at 265 points in which duration for a single point measurement is 5 minutes. The average activity concentrations of 238U, 232Th, 40K and dose rate obtained in this study are 38.97 Bq/kg, 50.56 Bq/kg, 935.267Bq/kg and 88.78 nGy/h, respectively. Although distinct radioactive anomalies were found in the studied area, the radiometric values showed some minor variations with slightly higher values than the normal level. As the result of this study, the average values of the absorbed gamma dose rate in air, radium equivalent activity, annual effective dose rate and the external hazard index were also calculated and examined in terms of radiologic hazard in this area. Consequently, all of the radiometric parameters are in good agreement with the regional surface geology of the Sarıçiçek pluton and its surrounding formation and there is no significant radiologic risk for humans and environment in and around this area.
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The First Steps for a Joint Romanian-Bulgarian Regional Early-Warning System for Marine Geohazards
Authors N.D. Dobrev, O.V. Dimitrov, G.P. Nikolov and K.S. KostovSummaryAn overview on the main hazardous geological processes endangered the Romanian-Bulgarian Black Sea coast with emphasize on hazards related to Bulgarian side, and goals and objectives of the Cross border project MARINGEOHAZARD whose purpose is to create key core components of a joint early warning monitoring system approved on both countries. The basic geohazards concerning Bulgarian part of the coast are presented. This includes historical strong earthquakes with tsunamis. The effects from the catastrophic earthquake with M7.2 occurred on 31 March 1901 near Kaliakra Cape have been described. The area is characteristic with large size landslide affecting strongly the North Bulgarian shoreline. The installed monitoring equipment included network of complex automatic marine measurement equipment, onshore network of online GNSS stations, extensometers, marine seismic monitoring equipment, etc. The first results obtained from 3D extensometric monitoring performed around Kaliakra Cape have been presented.
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Nonlinear Dynamics of Regional Cyclogenesis with Wind Speed Variations
Authors N.S. Erokhin, N.N. Zolnikova, L.A. Mikhailovskaya and R.S. ShkevovSummaryA numerical analysis of a self—consistent small parametric model (SPM) of a regional large scale cyclogenesis (RLSC) has been performed by usage of connected nonlinear equations for mean wind speed and ocean surface temperature in the tropical cyclone (TC) zone. These equations may describe the different scenario of temporal dynamics of a powerful atmospheric vortex during its full life cycle. By means of numerical calculations it is shown that relevant choice of SPM’s incoming parameters allows to obtain the seasonal behavior of regional LLSC with a given number of TC during the active season. In addition, the model allows describe the wind speed variations within the TC. So in the reference frame of the nonlinear small parametric model it is possible to study the features of RLSC’s temporal dynamics during the active season in the region given, to analyze the relationship between regional cyclogenesis characteristics and different external factors like the space weather.
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Determination of the Amplitude Values with Nakamura (H/V) Method and Standard Spectral Ratio (Ssr) Method at Ktu Campus
Authors Y.B. Beker, N. Sayil and Ö. AkinSummaryMicrotremor method used for engineering seismology is very important for determining of dynamic ground parameters and its variations. Method based on frequency of horizontal and vertical component microtremor records provides to quick and economical estimation of dynamic ground parameters. In this study, Nakamura (H/V) method and Standard Spectral Ratio (SSR) method have been applied to microtremor records taken with CMG-6TD three component broad band velocity seismometers in six profile with the aim of determining ground amplification of Karadeniz Technical University Campus area. The amplification maps of the study area are generated to the results of Nakamura (H/V) method and Standard Spectral Ratio (SSR) method and the results have been compared.
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Measuring Natural Radiation Backgrounds for Natural Hazard Evaluation in the Aspiring Buzău Land Geopark, Romania
Authors R.G. Popa and R. StochiciSummaryBuzău Land aspiring Geopark is a 1036km2 territory located in Romania, at the Carpathians Bend, in the close proximity of the Vrancea seismogenic area. Our work deals with natural hazards and risk in the aspiring Geopark territory. One of the hazards approached, which is the subject of this paper, refers to the exposure to natural radiation of inhabitants and visitors alike. Our work is still in progress, and we shall present its development so far. The measured values for radioactivity dose vary between 7.82 nSv/h and 56.83 nSv/h. Th levels vary between 1.38 ppm and 11.69 ppm, U levels vary between 0.31 ppm and 4.5 ppm and K levels vary between 0.32% and 2.12%. So far it seems that the natural radioactivity dose does not pose risk towards the inhabitants of Buzău Land Geopark or to its visitors, as the dose values are about 10 times smaller than the world average. We shall continue our measurements in order to optimally cover the entire territory and all lithological units, to have a comprehensive overview of the distribution of background radioactivity levels.
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Remote Sensing Observations of the Total Solar Eclipse and Incident Solar Radiation
Authors D. Krezhova, A. Krumov and K. KrezhovSummaryThe results from ground-based remote sensing investigations of changes of the environmental conditions (dramatic brightness reduction, local cloudiness, behaviour of the incident solar radiation) during the total solar eclipse on 29 March 2006 are presented. Series of digital images of the solar disk and corona as well as of a near-sun sky area were obtained during the all eclipse phases using a photometric CCD camera. Synchronous data for the dramatic changes and spectral behaviour of the incident solar radiation were collected by means of a portable fiber-optic spectrometer in the spectral range 350–1100 nm. The images were used to trace back the atmospheric conditions during the spectrometric measurements and to match the spectral data to the eclipse phases. The appeared fluctuations in the spectral behaviour of the solar radiation within several time intervals after the eclipse totality were caused by appearance of fine cloudy structures in front of the solar disk. We have found also changes in the spectral distribution of the solar radiation before and after the eclipse totality expressed in decrease of the solar radiation at the lower wavelengths and an increase in the spectral range after the spectra maximum due to the limb darkening effect.
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Imaging of Alpine and Post-Alpine Formations Using ERT at Loutsa- Remeri Open Pit Mine, Scourta, Viotia, Greece
Authors A. Vafidis, N. Andronikidis, H. Hamdan, I. Pyliotis, G. Panagopoulos, E. Manoutsoglou, L. Kikidis and N. BotosSummaryA geophysical survey carried out at Scourta plateau in Central Greece employed the electrical tomography method in order to image the interface between Alpine and Post-Alpine formations and estimate the thickness of Terra Rossa deposits. The later are crucial for TITAN-SA cement company open pit mine. This mine provides row materials for cement production. This survey is related with future extension plan of the existing Loutsa-Remeri open pit mine. Scourta is an active polje and is filled with a thick Terra Rossa deposit which is a row material for cement industry. The geophysical survey revealed two distinct layers, the upper is characterized by lower resistivity values (less than 20 Ωm), minimum thickness to the east (25 m) and maximum thickness at least 50 m and is attributed to Terra Rossa deposits. The underlying layer exhibits higher resistivity values (more than 70 Ωm) and is attributed to karstified carbonate relief. The variation of the polje depth is accosiated with tectonokarstic processes. The E-W direction fault system delineates the karstic structure and the N-S ridge in the east part of the survey area is delineated by N-S direction faults.
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Numerical Study of the Air Quality in the City of Sofia
Authors I. Georgieva, G. Gadzhev, K. Ganev, M. Prodanova, D. Syrakov and N. MiloshevSummarySome extensive numerical simulations of the atmospheric composition fields in the city of Sofia have been recently performed. The simulations were carried out using the following set of models: the model WRF used as meteorological pre-processor; CMAQ - the Community Multiscale Air Quality System — the chemical transport model; SMOKE - the Sparse Matrix Operator Kernel Emissions Modelling System — the emission model. As the NCEP Global Analysis Data with 1 degree resolution was used as meteorological background, the WRF and CMAQ nesting capabilities were applied for downscaling the simulations to a 1 km resolution over Sofia. The national emission inventory was used as an emission input for Bulgaria, while outside the country the emissions were taken from the TNO inventory. Special pre-processing procedures are created for introducing temporal profiles and speciation of the emissions. The biogenic emissions of VOC are estimated by the model SMOKE. Different characteristics of the numerically obtained concentration fields will be demonstrated in the present paper.
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Determination of Buildings Period and Vulnerability Index Using Microtremor Measurements
More LessSummaryMicroremor data has an important role on determining the ground dominant periods. Another way of use of the method is the application on the constructed buildings for investigating the strength and periods of each floor. It is possible to define the period of each floor and calculate the floor spectral ratio (FSR) parameter using microtremor data. This parameter is being used to estimate the transfer function (amplification, natural frequency and vulnerability index) of the buildings. In this study, microtremor data were collected in Folkart Towers which have a length of 200 m. The data were recorded at 14 floors for 40 minutes. The validation of frequencies were determined using FSR in order to obtain damping ratios accurately. The variation range and tendency between damping ratio and frequency of each floor with damping ratios and vulnerability indices, along with the preliminary influence factor, were presented and discussed. In addition, a fitting curve was plotted indicating the relation between the damping ratio and dominant natural frequencies of the floors. Furthermore, evaluation of strength, damping ratio, natural dominant frequency and vulnerability index of the building were estimated by interpreting microtremor data. The dominant frequencies of 44th, 22nd and 7th floors of the buildings were calculated as 0.4 Hz, 0.4 Hz–1Hz and 1.1 Hz respectively. It was determined that the buldings have 2 dominant periods. They are 1.1 Hz from 1st to 22nd floors and 0.4 Hz from 23 to 44th floors.
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Relationship Between Quasi Transfer Spectrums and Dynamic Amplification Factor
More LessSummaryQuasi Transfer Spectrums (QTS) and Dynamic soil amplification factor defining which ratio earthquake acceleration will reach the soil surface by changing is one of the most important factors in seismic risk studies. When computing the value of DAF at a point without a strong motion station, peak horizontal acceleration values at the bedrock and soil transfer function are needed. PGA value at the bedrock can be obtained by using either real seismic records or the earthquake scenario. However, the soil transfer function can be computed observationally and theoretically. Observational soil transfer function is defined by microtremor horizontal/vertical spectral ratio. In case of theoretical computation, the density belonging to the soil layers between the bedrock and the soil surface is used together with the change of P-S wave rates with the depth and the damping factor. In this study, the dynamic amplification factor has been computed for 57 points by using observational QTS obtained by microtremor horizontal/ vertical spectral ratio as well as the earthquake scenario. Also, theoretical soil transfer function at 1 point was obtained through spatial autocorrelation method study and determined to be compatible with observational result.
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Analysis of Reliability of the Microtremor Method
More LessSummaryMicrotremor method has often been used for determination of the fundamental frequency of the sediments covering the bedrock. Relatively, it is easier to apply than drilling, cost-effective and reliable method and has become widespread recently. There are some important issues that need to be considered during the measurements such as cultural noise level, recording time and terrain conditions. It is possible to obtain reliable results from this method, if both data collection and processing stages were carried out adequately. With respect to the suggestions of SESAME Project, the reliability of H/V curves and the apex on the H/V curve representing a possible ground resonance frequency were investigated. There are 3 main suggestions of SESAME Project in order to determine the predominant period (T0) and investigate the reliability of H/ V curves. These conditions are determining suitable number of windows, number of periods should be more than 200 and according to f0 value, standard deviation (σ) of H/V curve should be less than 3 if f0<0.5 Hz and σ<2 if f0>0.5 Hz. Besides, at least 5 over 6 criteria of SESAME Project should be proved in order to obtain a reliable result from the calculated apex of a H/V curve. Thus, the apex of H/V curve can be accepted as a reliable peak and this proves the observer to determine reliable ground parameters as well. In this study, output file of the H/V curve obtained from the evaluation of the microtremor data using Geopsy software was evaluated by an Excel-based program to examine the criteria determined in the context of the SESAME Project. Also the flowchart of the algorithm is presented. Data were collected from the Bornova district of Izmir. The measurements were analysed and the results were interpreted.
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Geophysical Characterization of the Havuzlu Landslide in Artvin Dam Area, Eastern Turkey
Authors K. Gelisli, S. Goren, H. Ersoy and C. CelikSummaryThe Artvin Dam and hydroelectric power station that has been built on the Çoruh River will have an average of production 1 billion kWH per year. It is far 20 km from south-west of the Artvin Province (Eastern Turkey). Havuzlu Landslide is located in a slope in boundaries of the Havuzlu village on the Artvin dam reservoir. The Havuzlu Landslide which has complex structure and including groundwater is paleo-landslide. The structure of paleo-landslide, potential sliding surface, possible fractures, crushed zones, geotechnical properties of formations and situation of groundwater were investigated by 2D electrical resistivity imaging method, self-potential (SP) measurements, microtremor and boreholes data. To calculation of slope stability possible sliding surface was determined between the landslide material and bedrock. Distribution of landslide materials along vertical and horizontal directions was determined. Structure of landslide mass and bedrock were extremely heterogeneous. Silty-clay and saturated zones were identified in the landslide mass. The crushed zones were estimated on bedrock layer. In the landslide area was calculated slope stability for three selected profile was demonstrated to be unstable.
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Geophysical Investigation for Environmental and Geotechnical Projects in the Lavrion Technological and Cultural Park
Authors G. Apostolopoulos, A. Kallioras, G. Amolochitis and G. MakrisSummaryA tailored geophysical investigation was designed to provide useful information in two of the activities/ priorities of the Lavrion Technological and Cultural Park (LTCP): a) identification of optimal location for the construction of an advanced Soil-Aquifer-System (SAT) which will be used to monitor geo-purification processes within the unsaturated zone; b) detection and mapping of an old (abandoned) mining tunnel that is envisaged to serve the educational purposes of the LTCP. Electromagnetic measurements in a regional and local mode have given useful information as a reconnaissance method in the positioning of the best area for the first activity outlining mainly areas of problematic anthropogenic features. ERT method clarified in a great detail the underground features in order to better design the structures for the two activities/priorities of the LTCP.
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Fracture System Mapping Using Pressure Probe Method
Authors S. Szalai, M. Metwaly, K. Szokoli, Á. Tóth and V. WesztergomSummaryMechanically weak zones may arise e.g. due to rock realignment in the subsurface having an effect to the near surface-, or even to the surface sediments. If they are not directly seen from the surface a new method, the so-called pressure probe (Pre-P) method may be used to detect and characterise them. This method is presented on the example of the investigation of the fracture system of a landslide. Repeatability of the Pre-P measurements, adequate sampling distance, resolution of the method and the possible data processing steps are also investigated. We know from these investigations that: 1. there are consolidated zones on the slope side of the fractures whose broadness correlates with the broadness of the given fracture; 2. both the large and the small fractures follow each other periodically; 3. even the structure inside the blocks which belong to the large fractures can be well seen which refers to the very good resolution of the method. The here presented Pre-P method seems to be the most favourable tool to map the fracture system of such kind of landslides according to its resolution capacity, speed, simplicity of its application, the interpretation of the data and its costs.
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Geotechnical Characterization of a Tailing Pond Dam
Authors Zs. Pronay, E. Törös, G. Taller and P. TildySummaryThere are about 30 tailing ponds of different size situated in Hungary. One of them was broken in 2010 and about 40 km2 was flooded by red mud causing 10 casualties and 140 injured. Since this incident Mining Authorities are responsible for the regular inspection of the dams. For testing the available geophysical methods intensive field tests were completed by the Geological and Geophysical Institute of Hungary to help the Authorities.
In this presentation the geotechnical and geophysical investigation of a selected tailing dam will be discussed. To investigate the dam 2D and 3D multielectrode DC method together with P- and Rayleigh-wave seismics and CPTu sounding was applied. There were triaxial or direct shear laboratory tests on undisturbed core samples as well. The geotechnical and lab results were compared with the values calculated using the seismic velocities.
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Application of ERT to Map Earth Fissures at the Valtotnera Area (Amyntaion, NW Greece)
Authors P. Tsourlos, G. Vargemezis and I. FikosSummaryIn this work we present the results of the application of the electrical resistivity tomography (ERT) technique into the mapping of the fissures that appeared in the Valtonera area (Amyntaion Munisipality, NW Greece). The results of ERT provide a satisfactory explanation to justify the expression of surface cracks in specific areas and this approach can be used to provide areas that are likely to be associated to fissures in the future.
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Application of Electrical Resistivity Tomography Method to the Mapping of Explored Caves and Detection of Possible New Chambers: Case Studies from Greece
Authors G. Vargemezis, I. Fikos and P. TsourlosSummaryCave detection and mapping is one of the most common targets of the resistivity method since the infinite resistivity of the air filled void of the cave is at a high contrast to the resistivity of any geological structure. In the case studies presented in this work (Maroneia and Andritsa, Greece) the caves are formed in limestone because of the karstification in addition to the local tectonics.
The geophysical method applied in both case studies is the Electrical Resistivity Tomography (ERT). The existing chambers have been observed in the resistivity models and new chambers are detected.
However, resistivity values attributed to the caves are of wide range. In Maroneia values of several thousand of Ohm.m have been measured while in Andritsa the values characterizing the chambers are small (maximum of 1610 Ohm-m).
The different behaviour of resistivities can be explained by the different geological formation hosting the caves and emphasizes the need for calibration measurements. This can be overcome with ERT measurements on the same geological formation but far from the surveyed area in order to measure the resistivity of the formation itself. In this case a forward modelling will suggest the expected values in the presence of a void.
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Sedimenthological Model of Lom Lignite Basin (North Bulgaria) - Integrated Use of Geophysical and Geological Data
Authors M. Yaneva and S.B. ShanovSummaryThe sedimenthological Model of Lom Lignite Basin (North Bulgaria) is represented by a set of maps, elaborated for the principal geological layers (sedimentary complexes) on the base of integrated analysis of data from boreholes, seismic profiling, seismic well logging, and vertical electrical sounding.
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Development of an Earthquake Shake Map Routine with Low Cost Accelerometers: Preliminary Results
Authors G. Tanırcan, H. Alçık and Y. KayaSummaryVast amounts of high quality strong motion data are indispensable inputs of the analyses in the field of geotechnical and earthquake engineering however, high cost of installation of the strong motion systems constitutes the biggest obstacle for worldwide dissemination. Today, for a high quality system, about 10,000 USD budget per instruments is required. In recent years, MEMS based (micro-electro-mechanical systems) accelerometers have been used in seismological research-oriented studies as well as earthquake engineering oriented projects basically due to precision obtained in downsized instruments. In this study two accomplishments were done. In the first phase; MEMS based instruments available in the Institutes’ inventory were modified so as to be used for real time monitoring. In the second phase a Matlab based shake map routine was developed to calculate various ground motion parameters in per-second basis only after triggered by an event. Hence, synchronized real time data transfer from instruments served to create a rapid response network in an affordable way. Functionality of the software has been investigated through shake table tests. The successful realization of this product also allowed us to set up a test network at Tekirdag Province, the closest city to moderate size earthquake activities in central Marmara Sea.
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Application of Machine Learning Method in Classification of Rock Types in Open Pit Mines
By H.S. NikolovSummarySupport vector (SV) method for classification originates from supervised machine learning methods. Although theoretically developed in the 70-ties of the 20-th century it was significantly improved in theory and practically implemented in the late 90-ties. Originally intended and elaborated as two class separation procedure it was latter transformed in robust multiclass classification technique. In this research the SV based technique for classification has been used for discrimination of rock types found in and around the open pit mines of Asarel-Medet mining complex located in the Srednogorie copper-porphyry mining region. The data used for the experiments are from the multispectral instruments TM/ETM+ onboard Landsat satellites from the same season of two different years. For ground trutning polygons having nomenclature under CORINE EU project were taken and adapted to the needs of this research. The results after classifying the area under study confirmed that the method selected is robust and offers good alternative to other approaches used for this task. In conclusions it is mentioned that for improvement of the outputs better spatial resolution is essential, but also more and narrower spectral bands would be offer an advantage.
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Remote Sensing Methods in Studying Stone Quarries
Authors D. Borisova, H. Nikolov, D. Petkov and B. BanushevSummaryIn Engineering and Environmental Geophysics different methods and techniques are applied. In this paper a remote sensing method has been tested in the segmentation of human made land covers such as open pit mines and stone quarries. The idea is to exploit to larger extent the possibilities offered by multispectral imagers having mind Thematic Mapper /TM/ onboard satellite series Landsat. The method has been used in the framework of our research is to find consistent statistical dependencies between multispectral data gathered in-situ and the corresponding ones in the images offered by airborne-based sensors. After correct identification of the pixels the subsequent segmentation forming the shape of the artificial feature is determined much more reliable. We have been combined ground spectrometry of stone quarry near Smolsko village, Landsat images of region of interest /RoI/, and in-situ condition surveys for assessment of the quarry area. For the purpose of the study geological observations, petrographical investigations, photo documentation and in-situ spectrometric measurements have been performed.
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Prospection of Wind Farm Site Using Geophysics
By P.S. SoupiosSummaryThe last decade, the use of geophysical surveys prior to completion of the initial subsurface monitoring and characterization for constructing wind parks, is very common. Geophysical models can provide critical, valuable, accurate and reliable information concerning the status of the ground on the site where the wind turbine are going to be founded and such information can be used by the engineers in the most appropriate and cost-effective way. This paper presents the use of surface wave method for the exploration of the subsurface in order to define the optimum places for wind turbine foundation.
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Strong Motion Network in the Bodrum Peninsula, Turkey
Authors H. Alcik, G. Tanircan, A. Korkmaz, O. Cirag and E. OzdemirSummaryThe Bodrum peninsula with a population of one million in summer season is one of the most populated touristic centers of the southwest coast of Turkey. The region is also located in one of the seismically active regions of the southeast Aegean Sea. Frequent occurrence of historical destructive and of instrumental earthquakes clearly demonstrates high seismic hazard in Bodrum and its surrounding area. Seismic activity has been monitored by three instruments located in the peninsula, however, currently there has been no strong motion network for use in generating parametric information for urban rapid response system after a damaging earthquake. Considering the high seismicity and high population of the region, a strong ground motion monitoring system, called as B-network, consists of 5 accelerometric stations was deployed on 2nd June 2015. Primary aims are to provide input for future earthquake rapid reporting and early warning implementation projects which turn out to be a crucial step and essential tool to mitigate the impact of strong earthquakes on urban environments in the Bodrum peninsula and the surrounding areas. So far the network recorded more than 5 local events (Ml>3.0). Preliminary analyses are underway. Possible future cooperation and coordination of mutual interests through joint projects may obviously give an opportunity to implement an empowered early warning system may serve to the whole region.
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Tsunami Modeling Scenarios for Some of the Seismic Sources in the Black Sea Area, Using Tsunami Analysis Tool Software
Authors R. Partheniu, M. Diaconescu, D. Ioane and A. MarmureanuSummaryAlthough a rare phenomenon, tsunamis in the Black Sea were generated in the past, studies showing more than twenty events observed ( Altinok Y., 1999 ). Earthquakes monitoring in the Black Sea as well as a database with tsunami modeling Scenarios could lead to a better understanding of such phenomena.
A set of 6 past earthquakes were taken into consideration for generating tsunami modeling Scenarios, using the earthquakes Depth, Latitude and Longitude as initial conditions. For preset parameters of fault dimensions and plane solution (Strike, Dip, Rake, Width, Length) a set of 36 different tsunami modeling Scenarios have been run, varying the Magnitude (Mw = 7, 7.5 and 8). These tests using the Tsunami Analysis Tool (TAT) software for modeling tsunamis in the Black Sea resulted in moderate to high tsunami waves, with the highest waves of 3.2 m, for an earthquake with M = 8 in Novorossisk area, generated at 15 km depth. Some of the Scenarios did not generate tsunami waves at all, for a Magnitude of 7 or 7.5.
The computations in this study need more thoroughness, in order to have a better correlation of the results from the tsunami modeling Scenarios and the tsunamis observed in the past.
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Study of Products from Neutrophilic Iron Bacteria by Prompt Gamma/Neutron Activation Analysis and X-Ray Diffraction
Authors K. Krezhov, R. Angelova and I. Sziklai-LaszloSummaryThe Fe(II)-oxidizing bacteria (FeOB) and Fe(III)-reducing bacteria (FeRB) were among the first groups of microorganisms to be recognized for carrying out a fundamental geological process - the bacterial iron redox cycling. The deposition of iron ions by the bacteria from the Sphaerotilus-Leptothrix group of neutrophilic FeOB is extracellular in the form of biogenic products contained in tubular structures (sheaths). We report on the determination of the concentration of elements in these products and the relative amounts of biogenic iron oxides/(oxy) hydroxides resulting from the bacterial metabolism. The Fe (II)-oxidizing organism was isolated from freshwater wetland surface sediments in Vitosha Mountain. Biogenic nanostructured materials were obtained after growing the genus Leptothrix in SIGP and Adler’s nutrient media. Formation of sheaths was observed only in case of dynamic cultivation in SIGP medium. High enrichment level of iron was found by the PGAA and NAA techniques in the products of cultivated isolates as compared to the reference sample (product of nature). Three iron oxide phases were found after cultivation in Adler’s medium: lepidocrocite (γ-FeOOH), non-stoichiometric magnetite (Fe3-xO4) and goethite (α-FeOOH). The cultivation in the SIGP medium yielded a single phase bacterial product — lepidocricite of poor crystallinity.
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Remote Sensing Techniques In Soil Degradation Detection
Authors R. Kancheva, D. Borisova and G. GeorgievSummarySoil salinization as a result of natural or human-induces processes is a serious global-scale problem. Numerous studies and efforts in assessing and controlling soil salinity have been made. Nearly sixty percent of the salt-affected soils around the world are in irrigated farmlands, and this trend is increasing. Salinization is a major reason for degradation of soil resources and decline of soil fertility. From an ecological and economic point of view it is extremely important to establish the occurrence and distribution of soil salinization as well as the intensity of the process. Remote sensing techniques are widely used in soil surveys to detect and map salt-affected areas. However, many constrain in monitoring and evaluating the spatial and temporal variability of the salinization process has been found out. Difficulties also arise in applying remote sensing to the assessment of slightly affected soils. The goal of this paper is to examine the spectral reflectance properties of soils with different degree of salinization and the feasibility of using spectral indicators derived from Vis/NIR data as detectors of salt-affected soils and quantitative estimators of soil salinity level.
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Subsurface Structure of Tympaki Basin (Crete, Greece) Based on Well and Geophysical Data
Authors G. Panagopoulos, E. Manoutsoglou, A. Vafidis, P. Soupios and S. BellasSummaryTympaki basin has been studied in the past years from a hydrogeological point of view. Whatsoever, less are known on the subsurface structure of the plain part of the basin in terms of sediments thicknesses and faults existence. A way of identifying in-ferred faults is the integrated use of geophysical and well-data which finally give an insight of the subsurface within a content of a well-established knowledge of the geo-logical regime of the study area. In this paper the use of 3D geological modelling technique is described as a mean to identify fault structures and horizon depths. The data used include the digital elevation model (DEM) of the area, the boundary sur-face between geologic formations and the litho-stratigraphic data from wells, geo-physical measurements of Vertical Electrical Soundings (VES) and Transient Electro-magnetic Method (TEM). The first step was to develop a 3D stratigraphic model that approximates the subsurface position of the Plio-Quaternary and the Neogene depos-its. The inferred faults came out from this model were cross-checked with the TEM measurements providing an updated subsurface structure. All the newly identified faults and along with the depth of stratigraphic horizons give finally an overall tecton-ic pattern of the Tympaki basin.
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Two Dimensional Joint Inversion of Seismic refraction, Radiomagnetotelluric and DC Resistivity Data: an example from Bafra plain, Turkey
Authors M.E. Candansayar, I. Demirci, A. Vafidis, P. Soupios, N. Economou, N. Andronikidis and H. ArslanSummaryA new two dimensional joint inversion algorithm for Seismic refraction, Radio-magnetotelluric and DC Resistivity data was developed. We used synthetic data to show advantage of the algorithm. The developed joint inversion algorithm found resistivity and velocity model better than the individual inversion of each data set if one compare with the real models. We also tested the algorithm with the field data collected in the Bafra basin to image the saltwater intrusion at this area. The field data inversion is also showed that the joint inversion recovered the resistivity and velocity model better than the individual inversion of each data set.
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Interpretation of IP Measurements Using an Inversion Based TAU-Transform Method
Authors E. Turai, M. Dobroka, E. Prácser, T. Ormos and Á. GyulaiSummaryThe paper presents the TAU-Transform of the Time-Domain IP curves and gives an approximate solution for TAU-transformation using inverse problem theory. A method for estimation of the type and the measure of soil contaminations will also be introduced. The determination of the contamination type (metallic or chemical) comes from the time constant spectra. The estimation of the soil contamination is based on the waited amplitude values of the time constant spectra. The application of the method is demonstrated in a contaminated industrial area in Hungary.
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An Investigation of Environmental Radioactivity Effects of Moloz (Trabzon, Turkey) Municipal Waste Dump Site
By H. ÇinarSummaryEnvironmental radioactivity level of the former Trabzon municipal solid waste dumpsite were investigated by in-situ gamma-ray spectrometric method. The natural radioelement concentrations on the surface of dumpsite were measured using a portable gamma-ray spectrometer. Spectrometry data were collected on the ground surface at 231 points along 21 profiles, parallel to each other, where the interval for both measurement points and each profile are 10 m. The measuring time was set to be 300 s at each point. The average activity concentrations of 238U, 232Th, 40K and dose rate in the dumpsite are 42.68 Bq/kg, 49.88 Bq/kg, 417 Bq/kg, and 67.91 nGy/h respectively. In addition, radiation hazard parameters were calculated and compared with the international standard values. Consequently, it was found that there is no significant radiologic hazard and risk for humans and the environment in studied area.
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Imaging the Saline/Fresh Water Interface at Bafra, Turkey Using Joint Inversion of Seismic Refraction and ERT Data
Authors H. Hamdan, E. Candansayar, I. Demirci, N. Economou, N. Andronikidis, H. Arslan, P. Soupios and A. VafidisSummaryA geophysical survey was conducted at Bafra, Samsun, Turkey, Greece in order to support the geological and hydrogeological studies of the existing phenomenon of seawater intrusion. This survey employed seismic refraction tomography (ST), time domain electromagnetic (TDEM) and geoelectrical methods.
The later, consisted of Electrical Resistivity Tomography (ERT). The objective of this survey was to image the saltwater intrusion at this area and map possible favorable sea water pathways. We present the interpretation of geophysical data obtained under the research project ClearWater project. We applied both individual and joint inversion of electric and seismic data from Bafra. At Bafra, the geophysical survey provided images of the saltwater intrusion which is present at the north eastern of the study area. These geophysical methods proved useful as prediction and prevention tools in qualitative characterization of water bearing formations for an optimum groundwater management plan for the Bafra basin.
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Application of Self-Potantial (SP) Method for Monitoring Contaminants Movement
Authors P. Soupios and M. KaraoulisSummaryThis paper presents the application of self-potential (SP) method in environmental application. The resulted SP model was compared with the resulted tomographic electrical resistivity models which acquired at the same time period with SP data. Both geophysical methods applied in Western Crete in Chania territory to delineate contaminants movements from a waste disposal site to the main river of Chania basin through the alluvial permeable formation. The main purpose of the SP method was the determination of the subsurface contaminants flow direction. The final resulted images showed a good correlation with geoelectrical resistivity model. The self-potential method has proved to be an important qualitative monitoring tool for assessing the environmental quality in contaminated lands.
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Preliminary Results from Lab Experiments on the Use and Sensitivity of Spectral Induced Polarization (SIP) Method
Authors K. Gerodimou, P. Kirmizakis, P. Soupios and A. VafidisSummaryThis paper presents the application of spectral induced polarization (SIP) method in a controlled laboratory experiment using known fluid concentrations. Specifically, we employed different fluid samples with variable concentration in order to record the temporal change of SIP response over time and test the sensitivity and reliability of SIP method. The SIP method has proved to be an important qualitative monitoring tool for assessing the environmental quality in contaminated lands.
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Investigation of Roadside Pollution Related to Traffic Density by Using Mangnetic Susceptibility Method
More LessSummaryThere is a rapid increase in traffic caused environmental pollution due to increasing population and number of motor vehicles. Especially many detrimental particles emitted by the vehicles reason grave soil pollution in roadsides. In addition, many scientific studies propose that these particles are detrimental for human health. Main purpose of this study is investigation of heavy metal pollution along several roadsides in city of İzmir by magnetic susceptibility measurements are often applied for investigating rock magntic properties, fire sites, landslide deposits, industrial, geothermal and soil pollution studies. Also one of the most frequent geophysical applications is traffic-related heavy metal pollution. In this study, magnetic susceptibility studies were carried out along the roads at Konak, Aliağa, Gülbahçe and Buca districts of İzmir. The measurements were performed by using MS2E high-resolution surface scanning device produced by Bartington Company. The Bartington Instruments MS2 Magnetic Susceptibility System became popular for use in the laboratory and field in universities around the world. The highest magnetic susceptibility value was observed, as 15 times higher than the normal value, along Çanakkale-İzmir highway which has the highest traffic density. Other study areas were Tınaztepe Campus road, Gülbahçe Village road and Konak-Bornova Highway and magnetic susceptiblity values were observed 6,7 and 14 times higher than normal values respectively. Consequently, it was determined that roadside pollution degree can be determined precisely by using magnetic susceptibility measurements.
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An Assessment of Groundwater Seepage beneath Dams Sites in Al-Bahah Region Using Resistivity Imaging
By B. AlhenakiSummaryThis study aims to conduct a hydrological evaluation of the wells located after the dams to estimate the ground nutrition of it through the geoelectrical. four dams are selected. A study is conducted by using electrical resistivity imaging for the study of layers and knowing the resistivity of underground water through dams. Results are shown as follows a semi complete discontinuation of feeding the wells located after the concrete dam and the ground dam which is considered the foundation of cement bases of both of them to reach the base rocks. it has become impossible for the underground water to leak through the dam. as a result, the wells located after the dam are not fed with the underground water. Rockfill dams and the wells located after the dams are not greatly affected due to the penetration of the underground water through sediments under the dam, feeding the wells. We recommend that the concrete dam is periodically and constantly opened to feed the sites located after the dam to avoid the depletion of wells. However, damage of the ground dam is lesser than the concrete dam due to the complete smooth movement of the surface water.
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Field Applicability of the g11n Configuration
Authors S. Szalai, V. Wesztergom, K. Szokoli, A. Frigy and E. PrácserSummaryFirstly a short introduction is given about the theory of the g11n configurations which belong to the group of the geoelectrical quasi null arrays. On the basis of our numerical investigations the application of these arrays seem to be rather perspective. Their field application is however difficult because of the complexity of the inversion of the data of these arrays. These arrays have very large geometric factor, they may change their sign and they can produce very sharp changes. Using an own developed code we inverted field data. The very first results show the field applicability of these configurations.
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Utilisation of Magnetotelluric Sounding for Geological Interpretation of Crustal Structures (Western Carpathians)
More LessSummaryIn the paper we present a geological interpretation of magnetotelluric sounding along the southern part of the seismic 2T profile situated in the southern Central Slovakia (Western Carpathians). The complexes with higher conductivity are imaged in the shallow depths, formed by the Tertiary sediments and volcanics. In the northernmost part of the profile, the influence of non-conductive complexes composed of orthogneisses and overlying Mesozoic carbonates is significant. In the central part of the profile, the low conductive granitoid complexes are superposed over the metamorphic rocks with higher conductivity. This structure is a remnant of the Hercynian middle crust nappes. The most outstanding phenomenon of the profile is the sudden, almost step, change in the conductivity parameters of the crust in the southern part. The significantly high conductivity of the crust in this area is most probably not related to its lithological composition, but by the abundant supply of fluids in the crust after the Neogene tectonic and volcanic processes.
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Aplication of the DC Resistivity Method to Landslide Study; Case Study - Church Ratesti
Authors D. Constantin, D. Constantin, S. Rasvan and P. RazvanSummaryIn the case were made three geoelectrical profiles, the first profile length 20 m, was located at a distance of 10 m west of the monastery direction. For research we used a Schlumberger device with AB = 2m and MN = 1 and I = 20 mA. Here, you see a fairly uniform distribution resistivity resistivity values ranging between 10–60 Ohmm. Area high resistivity depth is in the range AB / 2, between 2 and 6 m. In the interval AB / 2 5 to 30 m, resistivities are smaller, ranging between 2–10 Ohmm.
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Mapping the Bedrock Using ERT for Slope Stability Studies at Mavropigi Lignite Open Pit Mine, Northern Greece
SummaryThe application of the electrical resistivity method in geotechnical investigations is explored through a case study in Northern Greece. This method was employed at a lignite surface mining operation where fracture zones and discontinuities have been recently observed close to the pit boundaries. The main aim of the geophysical survey was to estimate the inclination of the contact between the Neogene and Schist/ Carbonates formations south of the pit. Two configuration arrays proved essential in such conditions, and helped improving the resolution of the geoelectrical section. The geoelectrical sections were then calibrated by boreholes indicating that the bedrock is dipping to the Northeast. Furthermore, the geophysical survey provided invaluable data regarding the geometry of the bedrock which was essential for the slope stability calculations.
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Preliminary Results of an ERT in a Vineyard in Estremoz, Portugal
Authors A.M. Correia and J. PassosSummaryIn 2014 a geophysical survey was carried out in a vineyard in Quinta do Mouro, in the wine region of Estremoz, in southern Portugal, to understand and study the geoelectrical characteristics of the soil. The main objective of the geophysical work was to delineate and characterize the soil and bedrock in geoelectrical terms in the vineyard’s area. The area has patches where high quality grapes are produced and patches which produce mediocre grapes. The geophysical survey aimed to try to understand if there was any correlation between the electrical resistivity of the ground (related with the amount of moisture in the ground) and the quality of the vines and grapes. The results indicate that, in this case, the quality of the vines and grapes appear to be related with the moisture in the ground, the good vines and grapes being associated with higher moisture content of the ground and so lower electrical resistivities.
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Results of Geoelectrical Surveys in the Area of Crater 70, Deception Island, Maritime Antarctica
Authors A.M. Correia and G. VieiraSummaryIn February of 2013 a geophysical survey using geoelectrical methods was performed in the Crater 70 area of Deception Island in Maritime Antarctica. The area suffered volcanic eruptions in 1967, 1969, and 1970. Two electrical resistivity tomography (ERT) profiles and a vertical electrical sounding (VES) were done with the objective of detecting and evaluating permafrost depth and thickness. By direct measurement along the two ERT profiles the depth of the frozen ground varied from 40 and 70 cm. The geophysical survey indicates that the frozen ground has an average thickness ranging from 3 to 6 m. Furthermore, the electrical resistivity of the frozen ground is about 4,000 Ω.m. Since the geoelectrical surveys were done over young volcano-sedimentary deposits resulting from the recent eruptions, it is possible to conclude that permafrost is recovering in the area.
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Geoelectrical Exploration of Mineral Deposits Using Gradient Array
Authors P. Georgescu and F. ChiteaSummaryInvestigation of deep structures by means of non-symmetric arrays in a complex geostructural assemblage lead to difficulties in delineating the shape of the ore body and the area of interest for future metal exploration.
In the presented case study, the gradient array was applied with the objective of detecting the lateral variation of electrical resistivity and metallic factor values. As the measured values and distribution of apparent resistivity and polarizability depends to some extent by the type of device used for prospecting and of its orientation in relation to geological structure, we analyse the influence of the used geophysical array by means of 3D theoretical modeling. It resulted that a conductive body will give an anomaly shape elongated towards a direction perpendicular on the injection (AB) line. The resulted information was used for enhanced field data interpretation.
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Geoelectrical and Geoelectromagnetic Imaging in Durusu Basin, Istanbul
More LessSummaryDurusu Lake is the biggest and the most important freshwater source which supports drinking water supply to the European side of Istanbul. The formation of the lake is related to the development of a dune barrier that separates the lake from the sea. Because of the importance of lake as a drinking water supply it is urgent to reveal the characteristics of the subsurface system of the narrow coast line between the lake and the sea. In this study (DCR) and (TEM) measurements were applied to detect possible saltwater intrusion and to delineate the subsurface structure in the north of Durusu Lake. When the inversion of these data is interpreted along with the hydrogeology of the area, it is concluded that the salt water intrusion along the barrier is not common and it occurs at a special area where the distance between lake and sea is very close. Along a measurement profile where lake and sea is nearest a water resistivity model was prepared by using borehole data nearby the profile and salt water intrusion was determined. This study revealed the place of clay lenses at the lake system and the influence clay lenses on the water cycle with geoelectrical images.
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Frequency-normalised Impedance for the Efficient Data Visualization in Magnetotellurics
By A.T. BasokurSummaryA concept of the frequency-normalized impedance (FNI) function is introduced for the visualization of all components of the magnetotelluric impedance tensor. This definition provides some useful properties to obtain an initial information for the subsurface resistivity distribution.
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Amalgamation of Satellite Remote Sensing and Geophysical Prospection for the Investigation of Ancient Cities: Two Case Studies from Demetrias and Pherai at the Region of Magnesia, Thessaly, Greece
Authors A Sarris, J. Donati, T. Kalayci, F. Simon, M. Manataki, C. Garcia and G. CantoroSummaryRecently a number of ancient cities in Greece have been studied through the use of geophysical techniques (Lolos and Gourley 2012, Sarris and Jones 2000, Tsokas et al 2012, Williams 2005). Magnetic and soil resistance techniques, and more recently the employment of GPR, were the main tools of exploration, but the limitations of technology made the extensive coverage of the cities a tedious task. The recent development of multi-sensor geophysical instrumentation and improved resolution satellite sensors have radically changed the investigation of archaeological sites. Within this framework, the GeoSat ReSeArch Lab of IMS-FORTH initiated a number of experimental campaigns at various sites to investigate the efficiency of the methodology in mapping the urban details of ancient cities. The whole operation fell under the scope of the POLITEIA-KRIPIS project (www.politeia.ims.forth.gr).
The integrated geophysical surveys at the Greek settlements of Pherai and Demetrias in Magnesia were carried out during March 2014, aiming to the identification of architectural features that could contribute to the study of the organization of the urban fabric of the two cities. Prior to the geophysical surveys, processing of satellite images was used as a guide of where geophysical measurements should focus.
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Imaging of Shallow Underwater Ancient Ruins with ERT and Seismic Methods
Authors G.S. Kritikakis, N. Papadopoulos, K. Simyrdanis and T. TheodoulouSummaryThe present geophysical research aims in evaluating the applicability of the Electrical Resistivity Tomography (ERT) and seismic (Multichannel Analysis of Surface Waves - MASW and refraction) methods on mapping shallow underwater ancient remnants. The preliminary results from a single seismic line and its corresponding ERT section (surveyed at the site of Agioi Theodoroi area located 10 km eastern of Heraklion, Crete, Greece) are presented. This work demonstrates that ERT as well as MASW are very promising geophysical methods for the delineation of underwater antiquities. High resistivity anomalies were attributed to building walls and are in accordance with some of their mapped outcrops. Furthermore, MASW method exhibits significant correspondence with ERT showing lateral S-wave velocity variations at the positions where the high resistivity anomalies exist. Surface waves traveling through the shallow sediments (Scholte-waves) demonstrate relatively low velocity values. This makes them suitable for the detection of relatively large (> 0.5 m) underwater manmade structures, providing the use of a high frequency source and thus, the creation of relatively short wavelengths (< 2 m). These preliminary results show the potential in employing modern tomographic techniques in the revealing the cultural dynamics in shallow off-shore archaeological sites.
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AncientCity - A new Frontier in Ancient Greek Urbanization through Geoinformatics
Authors N.G. Papadopoulos, J. Donati, G. Cantoro and I. MoffatSummaryAncientCity is a project consisting in the use of new perspectives in studying the ancient Greek urbanism through modern and advanced technological tools. The understanding, reconstruction and development of ancient Greek cities is approached through an integrated protocol composed of satellite / aerial remote sensing, multicomponent geophysical prospection and spatial analysis within a Geographical Information System platform. This approach involves the use of digital applications to detect patterns in the buried ancient built environment, the identification of surface and subsurface features through non-destructive archaeological fieldwork and the creation of digitized thematic plans of ancient Greek settlements. Five archaeological sites from two different greek geographical regions (central Greece and Peloponnese) were chosen to incorporate new urban models and recalibrate the traditional narratives about the development of the Greek city. The encouraging results of this integrated approach can be used as a prototype model for the employment of Geoinformatics in the historical and archaeological sciences within the subfield of Mediterranean archaeology and Greek Urbanization.
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Investigating the Interior of Tumuli: Problem Setting and Case Studies from N. Greece
Authors P. Tsourlos and G.N. TsokasSummaryThe geophysical techniques are used for investigating the interior of tumuli in order to locate burial monuments covered by the embankment. This is a contribution towards saving the integrity of the construction since the tumuli by themselves comprise monuments which must be preserved. The electrical resistivity tomography (ERT) comprises a fully non destructive, efficient and reliable method for investigating the interior of tumuli. Several examples on the conduct, processing and interpretation of ERT surveys data are presented here, all of which are coming from N. Greece. Further, comments on the merits and disadvantages of the method are made. The arrangement of the ERTs along rectangular and radial grids is also discussed.
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Geophysical Survey at the Area of the Ancient Theater of Aptera
Authors N.S. Spanoudakis, A. Vafidis, A. Paganis, N. Andronikidis, N. Hatzidakis and V. Niniou-KindeliSummaryIn this paper we present the latest results of the geophysical surveys performed during the autumn 2013 in Ancient Aptera, Chania, Crete, Greece. It is part of the continuous collaboration of the Applied Geophysics Lab, Technical University of Crete and the local Ephorate of Antiquities. The main scope of the geophysical studies is to detect buried structures in the area of the ancient theater. We managed to detect walls, pavements and a well utilizing GPR, magnetics, ERT and EM profiler.
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Data Integration in Archaeological Prospection - A Synthetic Approach
Authors M. Manataki, T Kalayci, N. Papadopoulos and A. SarrisSummaryGeophysical data integration in archaeological research is an emerging topic. As researchers increasingly have better access to multiple geophysical sensors it is now possible to use numerous techniques in order to explore different physical characteristics of buried phenomena. In return, a feature which is “invisible” to one sensor might be detected with another sensor so that a complete inventory of buried features might be achieved. Current research, however, usually investigates results of prospection in isolation and follows a simplistic comparative approach. In fact, “true” data integration in archaeological prospection may offer more information than sensors can individually provide (i.e. 1+1=3).
Variations in spatial layouts and physical characteristics of material culture, post-depositional processes, and complexity of natural background, all add significant task for the interpretation of archaeological prospection results. Therefore, evaluating the success of data integration remains as further challenge. In order to overcome this difficulty we can create a controlled environment with the help of geophysical model simulations. Artificially induced noise levels over simulation data may mimic complex natural environments and a measure of success may be calculated with the help of an original image.
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Low Enthalpy Geothermal Resource Development in India
By S.K. SharmaSummaryOil and gas have a head start on various other forms of energy. They are easily transported, easily converted and, in today’s market still relatively available. But due to its exhaustible nature, more attention is now needed to develop alternative non-conventional energy sources in parallel to keep the energy requirements going. It is in this context that the geothermal resources stands out as a promising long term salvation due to its bounty in nature among various non-conventional energy sources in India. Nearly 10,000 MWe power generation potential has been estimated from the total geothermal resource base in India and it can be used for space heating and cooling, heating of green houses for cultivation, cooking etc. especially in the high altitude and the colder regions. Geothermal springs are also used for balenotherapy and the promotion of tourism in several countries of the world. Electricity can be generated from geothermal fluids where higher temperatures are available with the help of binary power plants based upon the Organic Rankine Cycle (ORC).
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On the Fractal Behavior of the Total Organic Carbon in Shale Gas Reservoirs with an Example from the Barnett Shale (USA)
Authors S. Ouadfeul and L. AliouaneSummaryThe main objective of this paper is to show the behavior of the fractal analysis using the continuous wavelet transform in shale gas reservoirs. Analysis is based on the estimation of the so-called Hölder exponent by analyzing Total Organic Carbon (TOC) well-log using the continuous wavelet transform, the Morlet is the analyzing wavelet. Application to the TOC well-log data of a horizontal well drilled in the Worth basin (USA) where the main objective is the lower Barnett clearly shows no special behavior of the Hölder exponents in case of the sweet spots. We suggest application of the whole process to other well-logs data of shale gas reservoirs to compare results and generalize a rule about the fractal behavior in shale gas reservoirs.
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Natural Discharge Related Geothermal Evaluation of Carbonate Ranges, Example of Transdanubian Range, Hungary
Authors Á. Tóth and J. Mádl-SzőnyiSummaryReservoir, heat and fluid should be investigated for the study area during reconnaissance phase of a fluid-based geothermal exploration. Without proper borehole information the determination and evaluation of reservoir, especially heat and fluid are quite complicated. In turn, springs, which are natural discharge points of flow systems, can reflect the subsurface flow and temperature conditions, therefore they can provide information about the groundwater flow pattern and temperature conditions. Namely, characteristics of springs and their areal distribution can be indicative for gravity-driven groundwater flow systems, as well as geothermal potential via their outflowing water volume and temperature. Geothermal potential of the Transdanubian Range, Hungary was examined based on the results of multidimensional data analysis of natural springs. The modifying effect of geological build-up and basin geometry on groundwater flow and heat pattern, with special emphasis of heat accumulation for geothermal utilization, was analyzed by numerical simulations. The geothermal interpretation of the previous studies, statistical data analysis and numerical simulation led to the conclusion that siliciclastic cover is responsible for heat accumulation in carbonates therefore position of unconfined and confined parts is decisive in geothermal heat utilization in carbonates.
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Pre-production Pressure Evaluation for Geothermal Purposes in the Duna-Tisza Interfluve, Hungary
Authors S. Simon and J. Mádl-SzőnyiSummaryThe paper introduces the method of regional hydrodynamic analysis based on pore pressure evaluation into the preliminary geothermal evaluation, in sedimentary basins influenced by overpressured and superimposed gravity-driven flow. This novel approach complements the usual reservoir and temperature analysis. Understanding of subsurface pore pressure distribution is also beneficial during planning of thermal water reinjection. The approach is demonstrated for the Duna-Tisza Interfluve of the Pannonian basin and the results are compared with operational experiences. The results can give basis for numerical modeling and provide background for aligned utilization of drinking water, thermal water and hydrocarbons in sedimentary basins.
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Geothermal Anomalies of Gas Hydrate Deposit
By A. VasilevSummaryMeasurements of cruise MSM34 in the frame of the German project SUGAR of 11 heat flow stations in the BEEZ are the first in the Black Sea, purposefully conducted for gas hydrate (GH) study. Maps for the fields of temperature’s background and anomaly are gridded with different step and with stations within BSR areas exclusion from the input. Result of the maps’ analysis are three hypotheses: 1) GH deposit grows laterally with sequential addition of external subvolumes; 2) the cyclical process of GH subvolumes appearance consists of 7 subprocesses; 3) hypotheses 1 and 2 explain qualitatively the diversity of anomalous geothermal fields over GH deposits.
To confirm these hypotheses a 2D straight problem of conductive heat transfer is solved. Input parameters are data from MSM34 and publications from GH research in the region.
The results present geothermal evolution of key points in the study volume - curves of temperature (20) and heat flow (12) changes. The times to reach steady state are determined for the main 7 subprocesses. This work is a base for a new quantitative study of GH with the methods of marine geothermy.
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The Efficiency of Vertical Magnetic Gradient in the Discovery of Archaeological
By Mu ALmutairiSummaryThis report displays the magnetic surveys that were conducted at Archaeological site in the northwest of the Kingdom, along the line of 38˚03”08” east longitude and latitude 26˚30”14 north which is located within the province of AlUla approximately 400 m away from the town of al Medina.
Part of this area was selected with length of 40 meters and width of 20 meters for the purpose of the study based on surface phenomena in this chosen area, The use of vertical magnetic gradient.
The Gradient Magnetic data were processed using two different processing software for all surveyed Areas; to get more enhancements of results and to keep quality control. The magnetic response is different form high to low values, that is depend on the Magnetic susceptibility of geological, host materials and the hidden targets through it; on the survey area. This response of Gradient Magnetic methods were appear as variation anomalies which are indicated to a variation in the medium, and that interpreted as archaeological features, boundaries between buried rooms, walls, the existence of archaeological findings, buried walls and may be some of that walls are damaged and discontinued.
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High-resolution Geophysical Study of Somma-Vesuvius Offshore (Southern Italy)
Authors V. Paoletti, C. Marino, M. Fedi, S. Passaro and S. TamburrinoSummaryModern technologies in the field of marine geophysical surveys allow us to obtain accurate and detailed information on the characteristics of the seabed and the marine substrate. In this paper we present a new magnetic high-resolution map of the Somma-Vesuvius offshore (Gulf of Naples, Southern Italy) depicting some main volcanological and tectonic structures of the area. The analysis of a new marine magnetic dataset, acquired during the oceanographic survey “SAFE_2014”, highlighted the presence of a group of NNW-SSE trending anomalies. This magnetic alignment suggests a volcano-structural correlation with the major faults in the area. We was also identified a NE-SW trend of magnetic anomalies, which may be associated with a tectonic structures interpreted as a magma preferential path of Somma-Vesuvius. Furthermore morphological irregularities of the seabed, shown by new morpho-bathymetric data, were found in correspondence with some of the main magnetic anomalies of Vesuvius offshore. This confirms the hypothesis of a possible connection between the Vesuvian volcanic structures and the tectonic regime of the Gulf of Naples, which controls this region since the Neogene-Quaternary.
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Determination of Beam-position Dependent Transfer Functions for Tidal Recording LCR Gravimeters
Authors M. Kis, A. Koppán, J. Benedek, G. Papp, P. Kovács, L. Merényi, E. Szűcs and G. VadaszSummaryAuthors propose a method for the determination of transfer characteristics and fine calibration of LCR relative gravimeters without feedback system used for earth-tide recordings, by means of the moving-mass gravimeter calibration device of Budapest-Mátyáshegy Gravity and Geodynamical Observatory. Beam-position dependent transfer functions of two relative LCR G type gravimeters were determined and analyzed and a new anisotropic correction of long-time recordings was introduced based on the anisotropic transfer characteristics.
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First Results of an Investigation for the Ionospheric Conductivity Variation Using Lunar Tide
By C. CelikSummaryThe fundamental difference between solar, S, and lunar, L, is that L results from purely gravitational tidal movements. The difference in frequency between the L tidal movements and that of the ionospheric conductivity makes it possible to distinguish between the two effects, whereas for S the motions and conductivity both have the same frequency.The amplitude of lunar semi-diurnal tide, L2, was determined for each solar hour at an observation site of IZN, and compared with ionospheric conductivity.
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Consideration about Deep Structure in Vrancea Zone from Gravity Data
More LessSummaryThe paper objective is to contribute to the clarification of the deep structure of the curvature Carpathians Vrancea by gravimetric and geodetic data interpretation in plate tectonics concept, conceptual models of the lithosphere, able to explain the increased seismicity in this area. Developing models that help explain the lithosphere geological structure of the upper crust, helping to elucidate the causes which contribute to the production of intermediate earthquakes in the Vrancea area.
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The Impact of Geomagnetic Storms for the Energy Sector
Authors L. Asimopolos and N.S. AsimopolosSummaryThe growth in intensity of induced geomagnetic current scan affect terrestrial infrastructures such as power electric networks, oil and gas pipes, telecommunications cables and railway circuits. The practical importance of this subject consists of the fact that the networks of transport of electric energy are the most important ones from the point of view of the destructive effects of induced geomagnetic currents. Their effect increases with the extension of electric networks, including continental interconnections.
The intensity of the induced currents depends by the characteristics of geomagnetic field, the soil resistance in the area in which is carried out the coupling field with the power system components, the spatial extension of the coupling area, the treatment of neutral network in which occurs the phenomenon. The circulation of CGI in the system components produces abnormal operating regimes resulted, in most cases, with the disconnection of an important part of the network affected.
The larger and larger dependence of society on the availability, reliability and security of the energetic system is uncontested.
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An Amplitude/Phase approach to the Interpretation of Magnetic Anomalies
More LessSummaryAeromagnetic data is widely used to prospect for many different minerals. A first step in many exploration projects is the use of a semi-automatic interpretation method that provides initial estimates of source parameters that can be refined by later modelling and inversion. Many such techniques exist, such as Euler deconvolution ( Thompson, 1982 ) and the Tilt-Depth method ( Salem et al, 2007 ). This abstract shows that by separating the magnetic anomalies of dykes and contacts into amplitude and phase portions their dip can be obtained.
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Nonlinear Inverse Modeling of Magnetic Anomalies due to Thin Sheets and Cylinders Using Occam’s Method
Authors R. Ghanati, H.A. Ghari, M. Mirzaei and M.K. HafiziSummaryThis paper is focused on inverting geophysical magnetic data due to simple shape anomalies including thin sheet and cylinder using Occam’s inversion scheme. A significant aspect of using Occam’s inversion is the choice of the regularization parameter controlling the trade-off between the data fidelity and regularization term in the cost function of optimization problem, and consequently, reliable estimation of subsurface models. Two criteria L-curve and weighted generalized cross validation (W-GCV) are considered in order to choose an optimum value of the regularization parameter. The proposed strategy was first tested on two theoretical synthetic models for each of the magnetic simple-shaped structures with different random errors, where a considerable agreement was obtained between the assumed and calculated models. The validity of the technique was also applied to one real data set from Morvarid iron-apatite deposit, in Northwest Iran. The correlation between the results derived by the proposed algorithm and corresponding known geologic features was reasonable.
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Gravity and Magnetic Potential Fields for the Western Black Sea Region - Marine and on Land Maps with High Resolution
Authors B.K. Ranguelov, M.S. Bayraktutan, R.S. Radichev and A. S. KisyovSummaryDuring the sea and on land expedition campaigns (2011–2012–2013), complex geophysical measurements have been performed on the board of the specialised geophysical vessel “Mare Nigrum” – Romania. Then, after the data processing, several maps have been produced. The onboard measurements included high resolution bathymetry by multiple beam equipment, total magnetic field vector measurements by a marine magnetometer with high sensitivity, gravimetric on board measurements and salinity deep profiling from time to time. The marine complex geophysical measurement profiles have been separated by a distance of 1 km and covered the deep sea waters, limited to the coast by the waterline of the ship.
Two years later, on land measurements of the gravity field (Bouguer anomaly), total vector of the magnetic field and gamma radioactivity background, have been performed on surface elongated S-N single profile with a measurement step from 200–300 meters.
The purpose of these measurements was to support the creation of unified on land and marine maps.
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Determination of Discontinuities Using Bouguer Gravity Map of Hatay (Turkey) and Its Surroundings
By F. DogruSummaryEdge detection and edge enhancement techniques play an important role in interpreting potential field data. There have been various edge detection applications to gravity data in order to determine the edges of subsurface structures in geophysics. The edge detection methods comprise analytic signal, total horizontal derivative (THDR), theta angle, tilt angle, hyperbolic of tilt angle (HTA), normalised total horizontal gradient (TDX) and normalised horizontal derivative (NTHD). In this study, wavelet transform method and boundary analysis techniques are applied both synthetic models and field data. A Bouguer gravity data set from city of Hatay (Turkey) and its surroundings is used for field data and results are compared.
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Western Boundary of East European Platform in Romania as Interpreted on Gravity and Magnetic Data
Authors D. Ioane and I. CarageaSummaryThe geophysical detection of the western EEP boundary at crustal depths, south of the junction with the Carpathian Mts, represents an important geotectonic information when improving regional crustal models. Such geophysical and tectonic models are of great value in SE Europe, where the Vrancea seismogenic zone is generating high magnitude earthquakes at crustal and intermediate depths.
Satellite and ground Gravity and Magnetic regional data are integrated and interpreted in view of a better understanding of the TESZ southern continuation and location of the western EEP boundary.
The integrated interpretation of both satellite and ground Gravity and Magnetic data offers detailed information on the western boundary of the East European Platform at continental or regional scales.
The interpretation of gravity stripped map of Romania illustrated the EEP western boundary at crystalline basement depth and at lithospheric depth, respectively.
Based on the satellite magnetic and the gravity stripped maps, the eastern part of the Moesian Platform is interpreted to have geophysical EEP affinities (high magnetic properties and higher density) than its western part, the Intramoesian Fault being considered as a regional tectonic contact.
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Depth Determination of Simple Shaped Bodies from Gravity and Magnetic Anomalies by Using Walsh Transforms
Authors C. Sari, M.A. Gungor and F. UzunSummaryWithin the scope of this paper, Walsh transform was applied to the total magnetic field and gravity anomalies obtained from the ideal subsurface structures and the field studies and the possibility of this method for the calculation of the depths to the source structures was investigated. This method is based on the Walsh transformation which can be applied to the total magnetic field and gravity anomalies. In this method, initially normalized energy density (NED) spectrum, then the differential energy density (DED) spectrum would be obtained. DED spectrum is the difference between two successive sequency numbers of the NED. The maximum value of sequency numbers (Imax) on DED spectrum is determined and, the depth of the subsurface structure that caused the anomaly can be computed by using of this value in the proper equation. The monopole, line of monopoles, dipole and line of dipoles models were chosen as the ideal subsurface sources for magnetic and sphere, infinite extend horizontal cylinder and semi infinite vertical cylinder for gravity in the theoretical studies and and the anomalies of these structures can be calculated. The depths of the subsurface structures were estimated by using Walsh transform method to the field data and the obtained results were compared with the previously calculated depth with the various other methods. Furthermore, the theoretical and the field magnetic and gravity anomaly data were evaluated with using Fourier-Power Spectrum method.
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Investigation of Sultana and Sultan Hamam Walls at Topkapı Palace with Non-destructive GPR-CX Method
Authors C. Yalciner, Y.C. Kurban, E. Altunel, A. Buyuksarac, M.I. Topcu and E. BelceSummaryHamam structures, which hold an important place in the Ottoman İmperial and public, are notable for its architecture as well as durability. Sultana and Sultan Hamam at Topkapı Palace is one of the most important Hamam in Ottoman History, which constructed centuries ago. To investigate the robustness of this Hamam by non-destructive examination with the GPR-CX (Ground Penetrating Radar — Concrete Exploration) method was carried out.
Mainly GPR-CX method was improved for investigate modern concrete walls and systems, as well as the high resolution and speed with non-destructivity made the system suitable for ancient buildings. In this study 2.3 GHz HF antenna was conducted with a 100×100 cm grid area to all the walls of Hamam and the Tubulis (heat duct), lead water pipes etc. were discovered. In addition the metal clamps of wall connections were also found and contributed to the static studies.
By courtesy of non-destructive GPR-CX method, many unknown data were put forward about Hamam, which were constructed at 1460 AD.
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Investigation of Disturbance on Gallery Floor of Hagia Sophia Museum with GPR Method
Authors Y.C. Kurban, C.C. Yalciner, E. Altunel, A. Buyuksarac, M.I. Topcu and E. BelceSummaryThe Hagia Sophia Museum has an important place in both Byzantine and Turkish history, which was constructed by Emperor Justinian in 532 – 537 AD. After get over many large earthquakes and disasters, the Hagia Sophia Museum has maintained its existence until nowadays with repairs and renovations at various times.
In this study, the crack in the Gallery floor ground and the condition of the vaults, which are located between Gallery floor and the main hall of the Hagia Sophia Museum were investigated by GPR (Ground Penetrating Radar) method with 1 GHz HF (High Frequency) antenna.
The obtained data revealed quite clearly, the deterioration in the vault structure located under the Gallery floor. In the same time it has also revealed the work to strengthen the reinforced metal system made at this level. GPR results showed that, the strengthening work larger than the strengthening work mentioned in many older sources at the Hagia Sophia Museum, and these new results contribute to the future static studies. After this successful GPR study, the new project on the walls and the basements of the Hagia Sophia Museum was started with GPR and GPR-CX (Ground Penetrating Radar — Concrete Exploration) methods.
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GPR Survey at the Venetian Fortification Walls of Chania
Authors N. Spanoudakis, A. Vafidis and C. BourbouSummaryIn this paper we present the results of a Ground Penetrating Radar (GPR) survey for the detection of a demolished part of the Venetian walls of Chania, Crete, Greece. It is part of the collaboration of the local Ephorate of Antiquities and the Laboratory o Applied Geophysics, Technical University of Crete, for the detection of buried antiquities, for the urban planning of the city. The GPR time slices, depict a linear anomaly in the west to east direction which is interpreted as the extension of preserved parts of the wall.
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Employing CEEMD for Improving GPR Images - A Case Study from a Neolithic Settlement in Thessaly, Greece
Authors M. Manataki, A. Sarris and A. VafidisSummaryIn this study we apply Complete Ensemble Empirical Mode Decomposition on several GPR lines derived from a survey at Magoula Almyriotiki, a Neolithic settlement in Thessaly, Greece where buried structures are identified but are obscured by noise. The workflow we followed consists of a preprocess step (time zero, dewow, gain and background removal) followed by decomposition with CEEMD. The modes that exhibit less noise and at the same time gather all the reflections from the buried houses, were the third and the fifth IMF. Their summation was then used to calculate instantaneous envelope and to extract slices. From the obtained results the images are significantly improved highlighting further details of the buried antiquities, suggesting that CEEMD is a promising tool for processing GPR data when combined with standard filters and corrections.
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Performance of a Ground Penetrating Radar Antenna in Heterogeneous Environments
Authors C. Warren, I. Giannakis and A. GiannopoulosSummaryUnderstanding how energy is transmitted and received by Ground Penetrating Radar antennas is crucial to many areas of the industry: antenna design, data processing and inversion algorithms, usage of antennas in GPR surveys, and interpretation of GPR responses. The radiation characteristics of antennas are usually investigated by studying the radiation patterns and directivity. For GPR antennas it is important to study these characteristics when the antenna is in environments that would typically be encountered in GPR surveys. Physically measuring antenna radiation patterns in such environments presents many practical difficulties, and there have been very limited numerical studies that combine real GPR antenna models with realistic environments. This paper presents a numerical investigation of the radiation characteristics of a high-frequency GPR antenna in a realistic environment. An advanced modelling toolset has been developed that enables detailed models of GPR antennas to be used with realistic heterogeneous soil models. In this initial investigation small differences in directivity have been observed between a lossless dielectric environment and a more realistic environment featuring a heterogeneous soil model. These findings are part of an on-going full parametric study incorporating a range of different soils, fractal weightings and also the inclusion of rough surface modelling.
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Mapping of the Bauxite Ore Surface Using 3D Ground Penetrating Radar Data
More LessSummaryThe major goal of the study is test the ability of Ground Penetrating Radar (GPR) to determine the depth and thickness of bauxite layer at Az Zabirah town, north-central of Saudi Arabia. Bauxite is the most important aluminum ore. the 25 MHz frequency antenna has been used in this study insure better resolution of the subsurface and to get more penetration to image the Bauxite layer. (GPR) survey was conducted above 28 borehole, Where was taken seven profiles. Results showed the calculated total volume of bauxite in the survey area based on the GPR data is about 34696 m3 while that based on the borehole data is about 34101 m3. The minor difference in the calculated volumes (about 1%) indicates that the GPR data is more readable and could replace the borehole data or reduce the number of drilled holes.
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Investigating the Geophysical Characteristics of Gypsum through GPR
Authors M.S. Sari and Ö.B. BektaşSummaryGypsum crops out widely in the areas where the urbanization is intense in Sivas city center. In this study, in an appropriate selected area, geophysical characteristics and structure of gypsum have been investigated by applying geophysical methods of GPR (Ground Penetrating Radar). GPR measurements have been taken as 11 profiles with a Ramac GPR device by using 250 MHz shield-antenna. The distance between each profile has been taken as 2m and the length of each profile has been taken as 50m. All the area has been surveyed and ground radar sections have been obtained by GPR method. Gathering all the data, it has been found out that the areas with strong reflections (for the first 5m. depth) revealed in ground radar sections are not homogeneous massive gypsum bodies as presented in geological studies and contain different size and position fill material (clastic material). In addition, investigating such areas through GPR method has enabled to reveal the geophysical characteristics of the region as gypsum contains fractures-cracks, fillings and dissolution spaces.
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A GPR Study in the Roman Villa of Tourega, Portugal
Authors A.M. Correia, J.M. Maillol and B. BerardSummarySeveral radar surveys were conducted on the site of the Villa Romana da Tourega with a Sensors and Software ground penetrating radar (GPR). The main objective of the work was to test new GPR acquisition method. For this purpose, this site is ideal as it offers already excavated structures and very clear evidence of still buried continuation of these structures. For a successful completion of the tests in a timely manner it was necessary to have a high degree of certainty that buried structures were indeed present in the selected area. Only a portion of the results obtained during the field work are shown.
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Determination of Heavy Metal Contamination in Aliağa-İzmir Industrial Region with Magnetic Susceptibility Measurements
By C. SariSummaryEnvironmental pollution which is caused by industry increases with development of industry day by day. Especially hazardous particules including heavy metals are spread by industral plants cause health diseases on people and result with soil pollution. Main aim of this study is searching about heavy metals cause soil pollution and give damages to soil that are bruited by factories in industial zone and other plants. Field studies were carried out in an industrial zone in Aliağa district of İzmir. In Aliaga Industry District, the research about heavy metals cause pollution on the soil is done by applying measurements of magnetic susceptibility. Pollution investigation is performed in three different zones with the high resolution device produced by Bartington Company. While the expected mean values are between 0-50×10-6 cgs in the areas, the measured values are obtained higher 10 and 20 times than the normal values.
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To Determine a Place for the New Production Well by Seismic Inversion
Authors R. Aliev and T. AkhmedovSummaryIn this research work, we applied the most popular and effective method - Seismic Inversion. Seismic Inversion successfully fulfilled for this process. Our aim is to find a place of production well by Seismic Inversion. We used our special and new programs. Our programs differ from other companies’ programs.
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EUXINUS - Black Sea Security System - Two Years of Operation
Authors V. Radulescu, G. Oaie and I. SamoilaSummaryThe paper analyzes the first two years of activity of EUXINUS, the first early warning and monitoring system for marine hazards in the Black Sea, a network managed by the National Centre for Early Warning and Monitoring of the Marine Natural Hazards (GeoEcoMar - Constanta Branch, Romania). Since 2013, GeoEcoMar, as an institution dedicated to the research of the marine areas and using the financial support from the CBC Romania — Bulgaria Program, through MARINEGEOHAZARD Project (2010 – 2103), has built a complex network of three moored oceanographic buoys, one coastal gauge, a 2D seismic system (96 channels streamer), and an operational data center.
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Solar Influence on Decadal Climate Cycles over Balkan Peninsula
Authors Ya. Chapanov, M. Atanasova and N. NikolovaSummaryThe solar activity cycles affect various parameters of surface areas, including rains, snow covers, river streamflows and other hydrological cycles. These processes are due mainly to the total solar irradiance variations, followed by weather and climate changes. The interconnection between the solar cycles and decadal climate changes over Balkan Peninsula is investigated by means of reconstructed Total Solar Irradiance TSI, precipitation and temperature over Balkan Peninsula for the period 1766–2000 and measurements from station Sofia for 1901–2013. The decadal oscillations of precipitation, temperature and TSI with periods corresponding to the sunspots (11 years), solar magnetic cycle (22 years), equatorial solar asymmetry (45 years) and Gleissberg cycle (70–100 years) are compared and analyzed. The possibility to create decadal forecast models, based on solar activity cycles, are discussed.
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Drilling Technology Influence on Boreholes Quality with Geophysical Measurements Implications
Authors C Ciuperca, G.T. Jackson, B.M. Niculescu and B.M. PopinaSummaryThe drilling techniques and operations performed during drilling can affect the borehole’s shape and quality, with direct repercussions on the quality of geophysical records, both LWD and wireline. However, wireline measurements are more affected than LWD, due to the operations that occur after drilling the well (e.g., reaming trips, etc.) and the “aging borehole” phenomena (breakouts and fractures become larger, invasion becomes deeper).
The most affected by borehole’s quality and shape are the pad-type geophysical tools: Imaging, Litho-density or Microresistivity, which require a good contact with the formations. Also, the sonic logging readings can be affected by the occurence of quasi-horizontal or inclined fracture systems, due to a strong attenuation of the signal, causing the “time stretch” or even “cycle skipping” phenomena (abnormally long transit time readings).
Different types of fractures induced by drilling operations can create a false invasion appearance, since the resistivity tools with short investigation radii are influenced by the drilling fluid penetrating in these fractures.
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Imaging Folegandros Basin by Using Seismic Reflection Data from a Part of Seismic Line AEG-1
Authors N. Andronikidis, M. Gialitaki, A. Mouchou, G. Kritikakis, E. Manoutsoglou and A. VafidisSummarySeismic reflection data of the part of seismic line AEG-1 which crosses Folegandros basin in the south-central Aegean has been processed in order to image structures within this basin. The processing sequence included band-pass filtering for noise suppression, velocity analysis, tau-p filtering for multiple attenuation, zero phase deconvolution and post stack migration techniques. The seismic reflection method at Folegandros basin provided information about the geological structures at intermediate depths which is possibly related to tectonic elements and structures at greater depth. The evolution of Folegandros basin is explained by the action of wrench tectonics which can contribute to the understanding of multi - direction crustal- extension in the area.
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Anaximander Mountains and Deep Sea Mud Volcanoes South of Turkey
By M. SenozSummaryInitial stages of continental collision in the eastern Mediterranean Sea dominate the tectonic interaction between Africa and Eurasia, represented by the westward extrusion of the Anatolian microplate. The plate boundary is well defined through the Hellenic Arc to the west and through the Cyprus Arc to the east. The offshore Anaximander Mountains are an important link between the Hellenic and Cyprus arcs. They were formed by southeastward rifting from Turkey in post-Miocene time. Gravity data have shown that the eastern part of the Anaximander Mountains is different from the western part; multibeam mapping seems to confirm that the eastern Anaximander Mountains have affinity with the Florence Rise structure (western Cyprus Arc). Faulting along and across the latter feature is characterized in the seismic data by anastomosing faults and pop-up flower structures. It is likely that progressive adjustment to incipient collision developed into a broad zone of NW–SE transpressive wrenching extending towards south Turkey. In contrast, the western mountains are more directly related to the opening of the Rhodes Basin and the Finike Basin, as transtension may have dominated in southwest Turkey since the Pliocene ( A.E. Aksu et al.,2009 ). The connection with onshore Turkey is still unclear, but could be related to the Fethiye—Burdur Fault Zone that defines the western boundary of the complex Isparta Angle. The Anaximander Mountains and the Isparta Angle form together a tectonic accommodation zone between the active deformation in southwestern Turkey and the Aegean region and the tectonically quieter Cyprus region. ( T. A.C. Zitter, 2003 ) In the last years are in this area on tausends of kilometers sonar ; side scan sonar ; multibeam and multichannel seismic track lines new bathymetric data collected ( Lykousıs et al., 2009 ; A. E.Aksu et al., 2009 ). Detailed multibeam, sedimentological, and geophysical surveys provide ample new data to confirm that the Anaximander Mountains (Eastern Mediterranean) are an important area for active mud volcanism and gas hydrate formation. Very detailed morphology maps have been made of the known targeted mud volcanoes (Amsterdam, Kazan and Kula), especially the Amsterdam ‘‘crater’’ and the related mud breccia flows. New mud volcanoes identified on the basis of multibeam backscatter intensity were sampled, documented as active and named ‘‘Athina’’ and ‘‘Thessaloniki’’. Gas hydrates were sampled also in Thessaloniki mud volcano, the shallowest (1264 m) among all the active Mediterranean sites, at the boundary of the gas hydrate stability zone. Biostratigraphical analyses of mud breccia clasts indicated that the source of the subsurface sedimentary sequences consists of Late Cretaceous limestones, Paleocene siliciclastic rocks, Eocene biogenic limestones and Miocene mudstones. Rough estimations of the total capacity of the Anaximander mud volcanoes in methane gas are 2.56–6.40 km3.( Lykoısıs et al. 2009 ).
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Bathymetric Features of the Levant Basin on the Basis of Modern Processing Techniques
Authors E. Kokinou and H. KoppSummaryThe objective of the present work is to determine and partly interpret the sea floor morphological features in the Levant basin based on bathymetric analyses and taking into account previous geological and geophysical studies.
Bathymetry processing has been achieved by applying a new algorithm for the automatic enhancement and the identification of the linear patterns. According to this method, the Slope and Aspect images, as well as their derivatives are initially computed. Then, a rotation and scale-invariant filter produces an image of the automatic detected geomorphologic features in the study area.
The Levant basin comprises a geodynamically active area, where strong tectonic deformation takes part, resulting to the presence of extensional and contractional structures, strike slip motions, submarine landslides and density flows of sediments. All the previous phenomena are identified with sufficient accuracy in position and shape based on the bathymetric analyses of this work.
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A Newton-Raphson Approach for Geophysical Well Logs Interpretation in Complex Lithology Formations
Authors B.M. Niculescu and A. NEGUTSummaryThe paper presents a numerical algorithm that performs accurate lithology corrections for thermal (CNL/ TNPH, CNL/NPHI) and epithermal (SNP) neutron logs, in the whole range of porosities normally encountered in practice. It is known that neutron logs respond not only to a formation’s true porosity, but, to some extent, also to its lithology (the so-called “matrix effect”). Because the matrix effect is nonlinear and varies with true porosity, which is unknown beforehand, an iterative process is needed in order to carry out proper lithology corrections and obtain formation’s porosity.
The relationships between measured neutron porosity and true porosity for the common reservoir lithologies (sandstones, limestones and dolomites), at different formation water salinities, are approximable via suitable regression polynomials. Nonlinear neutron responses thus expressed are combined with the responses of density and sonic velocity logs, together with the volumetric unity constraint, into a system which is solved using a Newton-Raphson root finding routine. The algorithm, implemented as a set of Matlab™ codes, provides optimal petrophysical models for the interpretation of neutron-density-sonic log suites and is easily adaptable in order to include additional linear or nonlinear log response equations. A case study regarding its applicability is also presented in the paper.
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The Use of Magnetotelluric to Exploration the Groundwater in Central of Saudi Arabia
Authors RA ALmutairi, Y.A.A. almutairi, H.H.G. ALGHTANI, K.H.D. ALDAMEGH and E.S.S. ABOUDSummarySaudi Arabia is a desert country with no permanent rivers or lakes and very little rainfall. As such, ground water aquifers are major sources of water in Saudi Arabia. For example, in the Riyadh region (central of Saudi Arabia), several Wadies, including Wadi Nisah, store about 14 × 106 m3 which are extracted for local irrigation purposes. In most of these areas, water wells are as shallow as 200–300m. Wadi Nisah aquifer is important because it is a large subsurface water aquifer that could provide enough water for many years. Accordingly, a Magnetotelluric (MT) survey was conducted (for the first time in the Riyadh region) in order to evaluate the subsurface aquifers at great depths (∼ 2–3km). In this study, we used the available portable broadband sounding receiver system (MT24LF). This system is designed for measuring low frequency signals which penetrate the earth layers and directly related to the subsurface resistivity. MT results indicated that, a low resistivity layer associated with alluvium deposits was defined at depth of about 1–2km and extend horizontally to about 15km. We interpreted this layer as the subsurface ground water aquifer in Wadi Nisah.
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Thermal Water Sources and Features of Seismicity in the Elbasani Zone, Albania
By MR ShatroSummaryIn Elbasani fault zone, hot mineral water (thermal waters) spot out from natural springs which have been known since the 19th century. The thermal water zone correlates in space with seismic activity and compound earthquakes occurred. Activation of thermal water in this fracture zone is probably related to the feature of sismicity in this area. Thermo mineral and mineral waters of the area of Elbasan are located in the transvesal fracture Vlore-Elbasan-Diber. This fracture is one of the most interesting and unique tectonics of the geologic structure of the Albanids.In this area are located major thermal deposits like in Kozan region, where the most important one is Kozan’s Well −8, region of Lixha(Elbasan) and also the resources in the region of Hydraj.Moving southeast there are located the deposits of Galigati and Holta. Apart from the resources of Lixha and Hydraj, that have been known since the roman era, the wells of Kozan region,Galigati’s and Holta’s, have been showing in the surface,as a result of drilling these wells in order to seek for oil and gas.All the studies that were performed until today show that these resources have their origin in depth. Where geological conditions are favourable, rainwater seeps through the surface and becames trapped in vast underground reservoirs so deep below the Earth”s surface that it becomes heated to high temperatures by the low velocity zones. Thermal waters flow out through the contact of conglomerate layer with calcolistolith. The 24 October 2008 Kuturman (Elbasan) earthquakes sequence was a compound earthquake consisting of four nearly identical events. Low velocity layers can be promotore of geothermal energy inside it. Having high temperature in the low velocity layers in this area can creating the thermal-water. The low-velocity layer are characteristic for sizmoactive regions.
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Two Dimensional Inversion of Resistivity Data by an Adaptive Parameterization Approach
Authors I. Akca and C. Öztürk AkcaSummaryAn adaptive model parameterization methodology is used to develop a two dimensional inversion scheme for the direct current resistivity data. Adaptation is realized by a two stage inversion algorithm. The inverted model after the first stage of inversion is clustered to distinguish the target anomalies and the background. In the second stage a new parameter grid is formed by refining the model cells corresponding to the target bodies or structures. This methodology is well suited for the targets such as archaeological ruins, embedded bodies (tanks, bunkers) and cavities. A test with a synthetic data set is carried out to demonstrate the efficiency of the developed method. Results showed that algorithm is able to recover the subsurface image with more detail in comparison with the inversion results of the regular model mesh.
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Lithosphere-asthenosphere System in the Mediterranean Region in the Framework of Polarized Plate Tectonics
Authors R.B. Raykova, G.F. Panza and C. DoglioniSummaryVelocity structure of the lithosphere-asthenosphere system, to the depth of about 350 km, is obtained for almost 400 cells, sized 1°×1° in the Mediterranean region. The models are obtained by the following sequence of methods and tools: surface-wave dispersion measurements and collection; 2D tomography of dispersion relations; non-linear inversion of cellular dispersion relations; smoothing optimization method to select a preferred model for each cell. The 3D velocity model, that satisfies Occam razor principle, is obtained as a juxtaposition of selected cellular models. The reconstructed picture of the lithosphere-asthenosphere system evidences the, globally well known, asymmetry between the W- and E-directed subduction zones, attributed to the westward drift of the lithosphere relative to the mantle. Different relationship between slabs and mantle dynamics cause strong compositional differences in the upper mantle, as shown by large variations of seismic waves velocity, consistent with Polarized Plate Tectonics model.
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Seismic Coherence Driven Sparse Mesh for CSEM Inversion
More LessSummaryMany geophysical inverse problems involve large and dense coefficient matrices that often require an immense amount of computing power. Some methods can be used to reduce the processing time or physical memory required. This paper pose a significant challenge to solve large-scale inverse problems. We have developed a method that combines the adaptive mesh discretization and sparse mesh to reduce the computational complexity of CSEM inverse problems. The sparse mesh is created by Delaunay Triangulations method and constrained by seismic image. The nodes for generating triangular mesh are extracted from seismic coherence map. This sparse mesh is including all the information of geological features which are extracted from seismic image. A synthetic CSEM data are simulated for sparse mesh testing. As a result, the seismic coherence driven sparse mesh has an as high resolution inversion result as normal unstructured triangular dense mesh. Comparing with the same number unstructured triangular sparse mesh, seismic coherence driven sparse mesh has an advantage of vertical resolution.
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Optimization Methods for Least Squares Time Migrations
More LessSummaryLeast Squares Migration (LSM) is well known migration methods, but it is very expensive because of time. There are many optimization methods to improve LSM results. In this paper, five optimization methods, LSQR, Shooting, Grafting, Gauss-Seidel and Conjugate-Gradient are applied to data (SEG/ EAGE salt model) in order to obtain better migration results and to compare them in terms of quality, time and resolution. Tests have shown that the Gauss-Seidel method is the best method yields improved amplitude response, less time and higher resolution compared to others.
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SYstem for Modelling and INterpreting of GRavity ANomalies (SYMINGRAN)
By C.H. TzankovSummaryThe paper comprises new knowledge and at the same time improves cognition about some important issues related to modelling and interpretation of gravity anomalies in gravity exploration.
Useful algorithms for interactive modelling of varying geometric bodies with specific effective gravity attraction are developed. The analytical expressions concerning the form and the spatial relation of some geometrical models such as finite 3D horizontal circular cylinder and finite 2D horizontal elliptical cylinder are improved. This enhanced their technical qualities and flexibility through the modelling process.
In addition, all geometric models as well as the measured and the modelled gravity data are supported with original subroutines for visualization.
Moreover, the elements of the model are captured by a complex algorithm for simple real-time modelling which provides manual control of the model.
The optimization algorithms are based on Tikhonov regularization which means that additional heterogeneous information which stabilizes the solution of the inverse gravity problem could be included in the optimized models during the interpretation process.
The developed algorithms and programs are integrated into a single automated SYstem for Modelling and INterpreting of GRavity ANomalies (SYMINGRAN).
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Effect of Pressure on Compression, Shear and Young’s Moduli
Authors A. Kiss, J. Somogyi Molnar, M. Dobroka, T. Ormos and Á. GyulaiSummaryThe rocks response as perfectly elastic materials in case of rapidly changing stresses. With the assumption of the Hooke body, the elastic moduli describe how rocks resist different deformations. Present investigations covered the examination of pressure dependence of compressional, shear and Young’s moduli. As they can be calculated from the acoustic wave velocities (longitudinal and transverse) it is important to know accurately the velocity-stress function. Therefore the authors developed a petrophysical model, which gives the physical connection between the acoustic velocities and stresses. After estimating the model parameters by joint inversion, where the rock physical parameter is the common parameter, the velocities can be calculated at any arbitrary stresses and the pressure dependent elastic moduli can be derived. To prove the applicability of this method, we measured P and S wave velocities on sandstone samples with an automatic acoustic test system under uniaxial load. This paper includes one sample from these measurements together with literature data of a Berea sandstone sample. The results show that the misfits between measured and calculated data are small, the model can be applied well in practice.
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Laboratory P and S Wave Velocity Measurements to Confirm the Developed Petrophysical Model for Acoustic Hysteresis
Authors J. Somogyi Molnar, M. Dobroka, A. Kiss, T. Ormos, Á. Gyulai and E. PrácserSummaryIt is well known that acoustic wave propagation under pressure is very nonlinear and the elastic properties of rocks are hysteretic, which behavior is important for mechanical understanding of reservoirs during depletion. Pressure strongly influences the elastic parameters of rocks, thus wave velocities too. In this study longitudinal and transverse wave velocities measured in laboratory on sandstone samples under pressure are presented. The uniaxial loading of the samples was carried out by an automatic acoustic test system. Measurement data were processed by a joint inversion technique based on the developed petrophysical model which describes the relationship between acoustic P/S wave velocities and pressure for loading and unloading phases. After Birch we assume that the main factor determining the pressure dependence is the closure of pores. The advantage of the model is that it is not based on simple curve fitting, but gives physical explanation for the process with three-parameter exponential equations. The quality checked joint inversion results showed that the misfits between measured and calculated data are small, proving that the proposed petrophysical model can be applied well in practice.
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RefPick: A GUI Application to Pick First Arrival Times and Data Processing on Seismic Refraction Data
Authors K.H. Coban, M. Senkaya and H. KarslıSummaryThe quantified interpretation of the seismic refraction record depends on correct and confident picking first arrival times. However, traditional first arrival picking techniques are not enough if the refraction data are poor. This study presents the implementation of a GUI interface, RefPick, which has been established to detecting first arrivals on seismic refraction data, also data processing and inversion. While the interface allows picking the first arrival times by semi-automatically based correlation technique and manually, in addition, the seismic data can be filtered by f-k and Butterworth filters. The interface provides to export the first arrivals in the format of common evaluation software. Also, the inversion will be useful to invert the first data set within RefPick interface. By means of the RefPick, a seismic refraction data can be evaluated within one user-friend, open source GUI application.
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Anticlinal Structure Modeling with Feed Forward Neural Networks for Residual Gravity Anomaly Profile
Authors A. Eshaghzadeh and R.S. KalantarySummaryGeologically, Anticlines are the most important geological structures amongst regional studies and hydrocarbon exploration methods. In general, inversion of gravity anomalies is non-unique in the sense that the observed gravity anomalies in a survey can be explained by a variety of density distributions. To resolve such an ambiguity, the anomalous mass should be estimated by a suitable geometry with a defined density contrast.
Since anticlinal structures have mostly two non-isocline skirt, therefore utilization of the isosceles triangular model will be accompanied by a large error in the forward modeling. We have proposed using two adjoining right triangle for resolving mentioned problem. The density has been assumed constant. In this paper, a new method for anticline structure modeling based on feed forward neural network is presented.
The network is trained by synthetic data as input and output. For feed forward neural network training we have used the back-propagation algorithm. The results indicate that feed forward neural networks, if adequately trained, can predict the 2D form of anticline structure. The proposed method was applied to gravity data from Korand in Iran. The modeling results show high similarity with the attained results from seismic operation.
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Analysis of Capture and Surfatron Ultrarelativistic Acceleration of Electrons with Initial Relativistic Energy
Authors N.S. Erokhin, N.S. Erokhin, R.S. Shkevov, N.N. Zolnikova and L.A. MikhailovskayaSummaryThe ultrarelativistic acceleration of electrons in space plasma by an electromagnetic wave packet propagating across an external magnetic field is analyzed on the basis of numerical calculations. Electrons capturing conditions by the wave packet, dynamics of their velocity components and particle momentum are discussed depending on the problem initial parameters, including the size of the wave packet. The phase plane structure of the accelerated electrons is considered. The optimal conditions for the realization of ultrarelativistic surfatron acceleration of electrons by spatially localized wave packet are outlined. The occurrence of deviations and variations of the accelerated ultrarelativistic electron from cosmic rays standard power graph is discussed.
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Empirical Background TOC Model over Bulgaria
By P. KaleynaSummaryA detailed analysis of the variations of the stratospheric and mesospheric ozone over Bulgaria, in the period 1996–2012, is presented in the article on the basis of ground and satellite measurements of the Total Column Ozone (TCO). The move of the most important components has been studied. Their mean values for the period and the existing long-term trends have been found. It has been studied the move of the most basic components of the seasonal course, the existing long-term trends in it and their relations to the stratospheric temperature and quasi-biennial oscillation. Based on these studies and analyses, an empirical model for daily forecast of TCO over Bulgaria has been created. The main aim of the model is monitoring of the ozone layer and, respectively, the biologically harmful ultraviolet radiation of the Sun related to it which has an effect on human health and life.
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Moho Depth Determination of the Adriatic Sea Region Using a New Bouguer Anomaly Database
Authors G.A. Tassis, C.B. Papazachos, G.N. Tsokas, I.N. Tziavos, I. Vasiljević and A. StampolidisSummaryIn the present work we examine the crustal structure in the wider Adriatic Sea region using a newly presented Bouguer database derived from the integration of satellite, marine and inland gravity measurements. The observed large-wavelength Bouguer anomalies clearly correlate with the deeper crustal - upper mantle structural features, revealing new information on the Moho undulations, allowing the quantitative assessments of the Moho geometry in the study area. This task was performed using three different approaches, namely the multiple source Werner deconvolution (MSWD), the isostatic admittance method and the Parker-Oldenburg algorithm. The interpretation of the MSWD estimates was performed along nine selected Bouguer gravity profiles, leading to a pseudo-3D Moho map, as opposed to the other two methodologies from which 3D models are derived. All three maps exhibit similar large scale features but also local differences for the Moho structure in the Adriatic Sea area. Since this region exhibits complex geotectonic features, such as a double plate subduction, the main goal of the present work is to highlight the main areas of crustal thinning and thickening, using the aforementioned results. Moreover, the results provided by the different methods are evaluated against the current geological and geophysical data and models developed for the area.
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Seismic Monitoring for Automatic Rockfall Detection along Transportation corridor
Authors N. Economou, G. Kritikakis, A. Tripolitsiotis, P. Partsinevelos, G. Vlachou, Z. Agioutantis and A. VafidisSummaryThis geophysical research presents the setup and the preliminary results of several experiments conducted to evaluate the performance of seismic monitoring to recognize low energy ground vibrations caused by small rock free fall or rock rolling along a slope. New ideas for automatic rockfall detection based on Short Time Average over Long Time average (STA/LTA) and fractal analysis of the seismic records are introduced. Different events of vibrations were tested, such as random noise, passing cars or people, rolling or throwing rocks or combination of passing car with rockfall. Based on the experimental results it was determined that more than 95% of car stimulated records are discarded while, more than 90 % of rockfalls or simultaneous car passing and rockfalls are successfully recognized.
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