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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 7, Issue 4 - Nov 2004
Volume 7, Issue 3 - Aug 2004
Volume 7, Issue 2 - May 2004
Volume 7, Issue 1 - Feb 2004
Selecting the target year
Electrical Responses on the Auriferous Mineralized Bone in Sambo Mine
You Youngjune ; Yoo In-Kol ; Kim Jung-Ho ;
Geophysics and Geophysical Exploration, volume 7, issue 4, 2004, Pages 217~224
Self-potential and electrical resistivity methods were conducted for locating the auriferous mineralized zone, called Jija Vein, of Sambo mine, Limsu-ri, Haeje-myeon, Muahn-gun, Jeollanam-do. The host rocks of the mineralization include gneiss, rhyolite and felsic dyke. Ore vein is mainly fissured-filling type and sulfide minerals, such as pyrite, are disseminated in country rock. By the electrical responses from SP and surface resistivity methods., the mineralized zone is supposed to extend about 360 m directed N5W with the width of 20 m to 30 m. From resistivity tomograms using inclined borehole to surface, the ore body shape is interpreted as the width of 20 m in depth 40 m to 50 m.
Assessment of the Rock Strength using Borehole Acoustic Scanner
Lee Kwangbae ; Heo Seung ; Song Young-Soo ; Song Seungyup ; Kim Haksoo ;
Geophysics and Geophysical Exploration, volume 7, issue 4, 2004, Pages 225~233
The purpose of this study is to provide the geo-technical information by assessment of the in-situ rock strength using the reflected wave energy and travel time data acquired by the borehole acoustic scanner. In order to compare and analyze the relationship between the uniaxial compressive strength and the reflected wave energy, the laboratory test and the borehole acoustic scanning were conducted for the set of specimens, such as mortar, concrete, and rock samples which have different rock type. Finally, we verified the applicability of the reflected wave energy acquired by the borehole acoustic scanner to quantitatively estimate the in-situ rock strength.
3-D Traveltime and Amplitude Calculation using High-performance Parallel Finite-element Solver
Yang, Dong-Woo ; Kim, Jung-Ho ;
Geophysics and Geophysical Exploration, volume 7, issue 4, 2004, Pages 234~244
In order to calculate 3-dimensional wavefield using finite-element method in frequency domain, we must factor so huge sparse impedance matrix. Because of difficulties of handling of this huge impedance matrix, 3-dimensional wave equation modeling is conducted mainly in time domain. In this study, we simulate the 3-D wavefield using finite-element method in Laplace domain by combining high-performance parallel finite-element solver and SWEET (Suppressed Wave Equation Estimation of Traveltime) algorithm which can calculate the traveltime and the amplitude. To verify this combination, we applied it to the SEG/EAGE 3D salt model in serial and parallel computing environments.
Horizontal Distance Correction of Single Channel Marine Seismic Data
Kim Hyun-Do ; Kim Jin-Hoo ;
Geophysics and Geophysical Exploration, volume 7, issue 4, 2004, Pages 245~250
Horizontal-axes on the seismic section have been represented in a distance unit by applying horizontal-distance correction transformation on a 2-D seismic section of single channel marine seismic data. By drawing horizontal-axes in a distance unit, distortion of horizontal distances shown on the seismic section when the ship speed varies during a survey can be diminished considerably. Position information obtained by GPS and stored in each trace of seismic data as well as data collection windows were used for horizontal distance correction. The minimum window length was decided by considering ship speed and shot interval, and the maximum window length wat determined by reflecting radius of the 1st Fresnel zone. In choosing an optimum window length, horizontal resolution and stacking effect were considered simultaneously. By applying horizontal distance correction we could get a 2-D seismic section which is considered at reflecting the real subsurface structure analogously.
The Signal Distortion Due to the Electromagnetic Induction Inside a Cable
Jeong Ji-Min ; Choi Seong-Jun ; Kim Jung-Ho ; Song Young-Soo ;
Geophysics and Geophysical Exploration, volume 7, issue 4, 2004, Pages 251~255
Electric cables such as multi-interphone cables and ribbon cab]os are commonly used for data aquisition in the DC resistivity survey. In general, electromagnetic induction may occur in the electric cables when electric current flows through them. In case of using multi-interphone cables in the DC resistivity survey, electromagnetic induction could take place due to the entangled wires of the multi-interphone cables, when the current flows through them. Then, the electromagnetic induction may cause measured DC resistivity data to be distorted. In this study, a monitoring system with PXI (PCI Extention for Instrumentation) was constructed to examine signal distortion on the DC resistivity data, attributed to the electromagnetic induction. Common electric cables used in the DC resistivity survey were tested to observe the waveforms of the electric voltages. The waveforms measured were compared to examine signal distortion due to the electromagnetic induction. The results may provide information on the resistivity data obtained using different electric cables in the DC resistivity survey. The distortion of waveforms attributed to the electromagnetic induction wat not observed when using ribbon cables for DC resistivity data aquisition, while the distortion were observed when using multi-interphone. Therefore, the ribbon cables provide better quality of data than other cables in the DC resistivity data aquisition.
Archaeological Interpretation of GPR Data Applied on Wolseong Fortress in Gyeongju
Oh, Hyun-Dok ; Shin, Jong-Woo ;
Geophysics and Geophysical Exploration, volume 7, issue 4, 2004, Pages 256~261
This study grafts geophysics on modem archaeology and approaches with scientific and systematic methods to an excavation plan or archaeological study by means of GPR exploration which can assist archaeologists to study Wolseong fortress without excavating it. We investigated the areas in front of Seokbinggo (ice storage facility built of stone) and in the eastern corner of the castle with GPR. As a result, we detected 7 large squared building foundations, stone walls, an entrance for the fortress, many other foundation stones, a road and a garden.