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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Geophysics and Geophysical Exploration
Journal Basic Information
Journal DOI :
Korean Society of Earth and Exploration Geophysicists
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Volume & Issues
Volume 5, Issue 4 - Nov 2002
Volume 5, Issue 3 - Aug 2002
Volume 5, Issue 2 - May 2002
Volume 5, Issue 1 - Feb 2002
Selecting the target year
A 3 dimensional Visualization System for 3-D Seismic Data Analysis
Lee, Doo-Sung ; Kim, Hyoun-Gyu ;
Geophysics and Geophysical Exploration, volume 5, issue 2, 2002, Pages 71~77
We developed a modeling and visualization software that can analyze 3-dimensional seismic data. The software divides 3 dimensional space into a series of vertical and horizontal polygons, and allows the various seismic attributes and other spatial information to be stored on these polygons. The program can pick a particular pattern in semi-automatic mode, and store the pattern in the spatial DB. The pattern can be modeled and visualized in 3 dimensional space.
Resistivity Inversion of Underground Cavity Model Using a Multi-Resolution Wavelet
Suh Baek-Soo ; Lee Jae-Young ; Kim Yong-In ; Lee Chang-Hwan ;
Geophysics and Geophysical Exploration, volume 5, issue 2, 2002, Pages 78~83
The finite element method combined with the sensitivity method is adopted for 2-dimensionl Fourier transform inversion. To improve the efficiency of inversion calculation, multi-resolution wavelet method is proposed., Theoretical data which is obtained from above method is shown to examine the proposed method. Theoretical model assumes that underground cavity is located in limestone area. In theoretical model, 16 current and potential electrodes are located to get theoretical data. It is shown that the about inversion method is very exact and useful calculation method, in case the larger model is very small such as under ground cavity.
2.5 Dimensional EM Modeling considering Horizontal Magnetic Dipole Source
Kwon Hyoung-Seok ; Song Yoonho ; Son Jeong-Sul ; Suh Jung-Hee ;
Geophysics and Geophysical Exploration, volume 5, issue 2, 2002, Pages 84~92
In this study, the new modeling scheme has been developed for recently designed and tested electromagnetic survey, which adapts horizontal magnetic dipole with
frequency range as a source. The 2.5-D secondary field formulation in wavenumber domain was constructed using finite element method and verified through comparing results with layered-earth solutions calculated by integral equations. 2-D conductive- and resistive-block models were constructed for calculating electric field, magnetic field and impedance - the ratio of electric and magnetic fields which are orthogonal each other. This study showed that electric field and impedance are superior in identifying 2-D isolated-body model to magnetic field. In particular, impedance gives more stable results than electric field with similar spatial resolving power, because electric field is divided by magnetic field in impedance. Thus the impedance analysis which uses electric and magnetic fields together would give better result in imaging the shallow anomalies than conventional EM method.
A Case Study on 3-D Modeling of the Orebody by using the 3D Modeler
Lee, Doo-Sung ; Kim, Hyoun-Gyu ;
Geophysics and Geophysical Exploration, volume 5, issue 2, 2002, Pages 93~98
A three dimensional model for the orebody of an operating mine in Korea was constructed by using a program called '3-D Modeler'. The program allows the user to interactively construct a 3-D model of an orebody from its horizontal cross-sections. The 3-D Modeler is easily able to combine and display various spatial data for model construction. The result of modeling is strongly influenced by control points that correlate to the adjacent horizontal cross-sections. The control points are determined by comparing the geometrical shape of the adjacent cross-sections in conjunction with the geological features of the orebody. The resulting model can be evaluated in viewing the constructed object in three dimensional space or more closely evaluated by inspecting the cross-section. The model can iteratively be improved by modifying the shape of the cross-section and by using this new cross-section for the model building.
A Study on the Finite Difference Forward Modeling in SASW Method
Ha, Hee-Sang ; Shin, Chang-Su ; Seo, Jung-Hee ;
Geophysics and Geophysical Exploration, volume 5, issue 2, 2002, Pages 99~107
An analytical forward modeling algorithm was developed for the efficient application to the geotechnical engineering in SASW (Spectral Analysis of Surface Waves) method. for the theoretical dispersion curve, the finite difference method using motion stress vector, which was proposed by Aki and Richards, was employed and verified with two earth models. For the stable and fast calculation, it was found that the model size depending on the frequency range is suitable
times bigger than the wavelength.
Interpretation of Finite HMD Source EM Data using Cagniard Impedance
Kwon Hyoung-Seok ; Song Yoonho ; Seol Soon-Jee ; Son Jeong-Sul ; Suh Jung-Hee ;
Geophysics and Geophysical Exploration, volume 5, issue 2, 2002, Pages 108~117
We have introduced a new approach to obtain the conductivity information of subsurface using Cagniard impedance over two-dimensional (2-D) model in the presence of horizontal magnetic dipole source with the frequency range of
. Firstly, we designed the method to calculate the apparent resistivity from the ratio between horizontal electric and magnetic fields, Cagniard impedance, considering the source effects when the plane wave assumption is failed in finite source EM problem, and applied it to several numerical models such as homogeneous half-space or layered-earth model. It successfully provided subsurface information even though it is still rough, while the one with plane wave assumption is hard to give useful information. Next, through analyzing Cagniard impedance and apparent resistivity considering source effect over 2-D models containing conductive- or resistive-block, we showed that the possibility of obtaining conductivities of background media and anomaly using this approach. In addition, the apparent resistivity considering source effect and phase pseudosections constructed from Cagniard impedance over the isolated conductive- and resistive block model well demonstrated outlines of anomalies and conductivity distribution even though there were some distortions came from sidelobes caused by 2-D body.
Hydrogeologic Structure derived from Electrical and CSMT Surveys in the Chojung Area
Song Sung-Ho ; Yong Hwan-Ho ; Kim Jin-Ho ; Song Seung-Yup ; Chung Hyung-Jae ;
Geophysics and Geophysical Exploration, volume 5, issue 2, 2002, Pages 118~125
The hydrogeologic structure in the Chojung area was evaluated from a set of geological and geophysical investigations: detailed geological survey, vertical electric sounding (VES), borehole logging, and controlled-source magnetotelluric (CSMT) survey. Among these, CSMT soundings were taken for integrated interpretation to extend hydrogeologic structure with depth. The result of CSMT survey along with VES and borehole logging provides the vertical geologic boundary connected with hydrogeologic structure, and also indicates the depth of aquifer in granite basement. To interpret the geologic boundary and aquifer characteristics using CSMT data, we adopted the technique of 1-D inversion with smoothness-constrained method and 2-D continuous profiling with 1-D Bostick inversion and spatial filtering. The methodology tested and adopted in this study would be useful and required for providing a more information to the structure of fractured aquifer system.
A Study on 125-point Weighted Average Coefficients for Sc81ar 3-D Wave Equation Modeling
Lee Dongkweon ; Shin Chang-Soo ;
Geophysics and Geophysical Exploration, volume 5, issue 2, 2002, Pages 126~134