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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 8, Issue 4 - Nov 2005
Volume 8, Issue 3 - Aug 2005
Volume 8, Issue 2 - May 2005
Volume 8, Issue 1 - Feb 2005
Selecting the target year
Climatic Characteristics Related with Sedimentary Process in Bransfield Strait, Antarctica
Lee, Bang-Yong ; Kwon, Tae-Yong ; Lee, Jeong-Soon ; Yun, Ho-Il ; Yun, Yeong-Jun ;
Geophysics and Geophysical Exploration, volume 8, issue 4, 2005, Pages 173~185
This study examines the relationships among sea ice concentration, surface air temperature, surface wind, and SST (Sea Surface Temperature) in Bransfield Strait to understand the climatic characteristics and its related sedimentary process there. In analyses of the monthly data, during the austral autumn (Mar., Apr., and May), the frequency of southeasterlies is correlated positively with the sea ice concentration and negatively with the surface air temperature, whereas that of northwesterlies is reverse. These relationships are explained by the process that the southeasterlies of the cold air from the Antarctic Continent affect the ocean current around Bransfield Strait. And then the ocean current makes the sea ice generated in the Weddell Sea drift into the strait. During the spring (Sep., Oct., and Nov.), sea ice concentration and surface air temperature are closely correlated with the frequency of northwesterlies with warm air mass. In the some parts of the northern boundary region, the sea ice concentration in Bransfield Strait is positively correlated with the SST during the autumn and spring. Such relationship may rather propel the sea ice melting in proportion to the sea ice concentration during the autumn.
Side-scan sonar survey in the Pechora Sea, Russian Arctic
Jin, Young-Keun ; Chung, Kyung-Ho ; Kim, Yea-dong ; Lee, Joo-han ;
Geophysics and Geophysical Exploration, volume 8, issue 4, 2005, Pages 187~194
As a study of Arctic marine survey project, Side-scan sonar survey was carried out in the Pechora Sea belonging to the southeaster part of Barents Sea. The study area is a shallow sea 11 m-16 m deep with recent sediments of rich organic carbon. Side-scan sonar profiles show large-scale marine plant communities 2-3 m wide covering the southeastern area. A lot of lineaments are traced on the seafloor in the central and northern area. The major trends of the lineaments are 220°and 290°(WSW-ENE and WNW-ESE). This trends is thought to be a main path of icebergs. Pockmarks on the seafloor are locally distributed in the area, which are formed by fluid and/or gas discharge. These would be related with petroleum/gas system well developed around the study area. Dut to weak appearances and limited distribution of the pockmarks, more detailed studies are necessary to examine their nature and structure.
Some Questions Related to The Design of Soil Nails
Chang, Ki-tae ; Milligan, G.W.E. ;
Geophysics and Geophysical Exploration, volume 8, issue 4, 2005, Pages 195~199
Flux Footprint Climatology and Data Quality at Dasan Station in the Arctic
Lee, Bang-Yong ; Choi, Tae-Jin ; Lee, Hee-Choon ; Yoon, Young-Jun ;
Geophysics and Geophysical Exploration, volume 8, issue 4, 2005, Pages 201~205
Turbulent fluxes of heat, water vapor, and CO2 have been measured since August, 2003 t Dasan Station (78o 55’ N, 11o50’E) in the Arctic. These data can allow us to better understand the interactions between the Polar ecosystems and the atmosphere together with those at King Sejong Station in the Antarctic. Due to the buildings and measurement platforms around the flux tower, it is required to evaluate how they influence measured flux data. By using one-year turbulence statistics data and footprint model, flux footprint climatology was analyzed together with data availability. The upwind distance of source area ranged from 150 to 300 m, where the buildings and measurement platforms existed. However, flow distortion due to them may be not a major factor to reduce the data availability significantly. Based on, the dominant wind direction of SW and footprint climatology, the location of flux tower is considered suitable for flux measurement.
Review on M
Scales in Southern Korea
Shin, Jin-Soo ; Chi, Heon-Cheol ; Cho, Chang-Soo ;
Geophysics and Geophysical Exploration, volume 8, issue 4, 2005, Pages 207~209
The local magnitude scales yield in the Southern Korean Peninsula following the Richter's original definition are reviewed. In order to compare the previous ML scales, the new distance correction term of ML scale is derived as - log A
= 1.017 log ( r/17) + 0.00028 ( r-17)2 + 2 .0 using broadband velocity seismograms from 126 local events occured from 2000 to 2004. The attenuation rate of this formula fall between those of western and eastern North America. This result is in nearly accord with the ML scales proposed by Kim and Park(2002). The differences between various ML scales is owing to insufficient seismic data not to distribute whole area of Southern Korea.
Analysis of Distortion Effect of Resistivity Data Due to 3D Geometry of Fill Dam
Oh, Seok-hoon ; Kim, Hyoung-Soo ;
Geophysics and Geophysical Exploration, volume 8, issue 4, 2005, Pages 211~214
Low resistivity zone is observed at the lower part of a CFRD (Concrete Face Rockfill Dam). Generally, CFRD tends not to have any saturated zone within the body, but the result of resistivity survey shows that it is possible for the dam to be saturated under 20m depth with water. The level of reservoir was under 10 m from the crest. We suspect that this result may come from the wrong 2D inversion process ignoring the 3D geometry of dams. For the analysis of possibility of distortion by different geometry, we perform the 3D forward modeling for the dam and apply the 2D inversion process. And then we check the point of traditional interpretation of resistivity data. By the analysis, it is found that the result of 2D inversion process of 3D geometry of dams, seems to have deep relation with the reservoir level, and the complex 3D structure hide some internal electrical anomaly of dams from resistivity information.
Tectonic Features along the South Scotia Ridge, Antarctica
Hong, Jong-kuk ; Jin, Young-Keun ; Lee, Joo-Han ; Nam, Sang-Heon ; Park, Min-Kyu ;
Geophysics and Geophysical Exploration, volume 8, issue 4, 2005, Pages 215~219
Multichannel seismic survey has conducted along the South Scotia Ridge which is located in the northern part of Weddell sea, Antarctic sea. The South Scotia Ridge is part of continental crust extended from Antarctic Peninsula. It borders on Oceanic plates, the Scotia sea plate and Powell basin. Transtensional tectonics along the sinistral transform fault plate boundary led to the creation of the present tectonic geomorphology of the South Scotia Ridge. The fan-shaped deposits with angular unconformities in the central depression is interpreted as a divergent tectonic movement along the ridge.
Seismic Refraction Analysis to Estimate the Depth to the Bedrock: Case Study
Lee, Doo-Sung ;
Geophysics and Geophysical Exploration, volume 8, issue 4, 2005, Pages 237~242
A seismic refraction study in estimation of depth to the bedrock demonstrates that 1) the average velocity in the medium is about 250 m/s in the surface layer (< 4 m), 2,500 m/s in the weathered formation, and greater than 3,000 m/s in the bedrock, 2) the depth to the deepest reflector assumed to be the bedrock is about 17 m; however, according to the cores collected in a borehole in study area, the bedrock (granite) occurred at depth 25 m, 3) according to the density and velocity logging, at depth 17 m, a measurable velocity and density increase are observed, and 4) the velocity of the weathered formation is relatively high and therefore, the acquisition offsets (
) are turned out not to be long enough to record the refracted signal from the bedrock at depth 25 m as first arrivals.
Late Quaternary Stratigraphy and its Depositional History in the Inner Shelf off the Southern Coast, Korea
Yoo, Dong-Geun ; Lee, Ho-Young ; Park, Keun-Pil ; Koo, Nam-Hyung ; Kim, Jong-Chon ;
Geophysics and Geophysical Exploration, volume 8, issue 4, 2005, Pages 243~250
Analysis of high-resolution seismic profiles acquired from the inner shelf off the southern coast of Korea reveals that the inner shelf sequence can be divided into three stratigraphic units formed after the Last Glacial Maximum (LGM). Unit I is characterized by complex seismic facies including semi-transparent, stratified, and hummocky reflections on seismic records. It consists of sandy mud or muddy sand, deposited under estuarine environment during the post-glacial transgression. Unit II acoustically shows semi-transparent or hummocky reflections and consists of sand with gravels and shell debris, produced by shoreface erosion during the transgression. Unit III is characterized by transparent or semi-transparent seismic facies and consists of mud originated from the Nakdong and Seomjin rivers during recent highstand of sea level. Unit III is confined to the inner shelf with an extenal form of stratal wedge.
Prediction of Electromagnetic Noise using Spatial Modelling in Magnetotellurics
Lee, Choon-Ki ; Lee, Heui-Soon ; Kwon, Byung-Doo ;
Geophysics and Geophysical Exploration, volume 8, issue 4, 2005, Pages 251~261
The quality of MT (magnetotellurics) data highly depends on the level of artificial noise form industrial sources. We have conducted the feasibility study of MT noise modelling using digital spatial data and spatial modelling through the comparison between the predicted and the measured MT noises. A simple noise model predicting the intensity of electromagnetic field radiated from the latent noise sources, that is, the electric facilities in the building, road and high-voltage powerline, is developed in consideration of the propagation property of electromagnetic waves. From the analysis of correlation between the predicted and the measured noise power, the correlation coefficients of electric field are higher than those of magnetic field in whole frequency band. The magnetic field component has the high correlation in the narrow band near 60 Hz only. The spatial noise modelling proposed in this study would provide some useful informations for the MT surveys in the noisy environment like urban area.
Effective 3-D GPR Survey for the Exploration of Old Remains
Kim, Jung-Ho ; Yi, Myeong-Jong ; Son, Jeong-Sul ; Cho, Seong-Jun ; Park, Sam-Gyu ;
Geophysics and Geophysical Exploration, volume 8, issue 4, 2005, Pages 262~269
Since the buried cultural relics are three-dimensional (3-D) objects in nature, 3-D survey is more preferable in archeological exploration. 3-D Ground Penetrating Radar (GPR) survey based on very dense data in principle, however, might need much higher cost and longer time of exploration than other geophysical methods commonly used for the archeological exploration, such as magnetic and electromagnetic methods. We developed a small-scale continuous data acquisition system which consists of two sets of GPR antennas and the precise positioning device tracking the moving-path of GPR antenna automatically and continuously. Since the high cost of field work may be partly attributed to establishing many profile lines, we adopted a concept of data acquisition at arbitrary locations not along the pre-established profile lines. Besides this hardware system, we also developed several software packages in order to effectively process and visualize the 3-D data obtained by the developed system and the data acquisition concept. Using the developed system, we performed 3-D GPR survey to investigate the possible historical remains of Baekje Kingdom at Buyeo city, South Korea, prior to the excavation. Owing to the newly devised system, we could obtain 3-D GPR data of this survey area having areal extent over about
within only six-hours field work. Although the GPR data were obtained at random locations not along the pre-established profile lines, we could obtain high-resolution 3-D images showing many distinctive anomalies, which could be interpreted as old agricultural lands, waterways, and artificial structures or remains. This cast: history led us to the conclusion that 3-D GPR method is very useful not only to examine a small anomalous area but also to investigate the wider region of the archeological interests.
GPR Development for Landmine Detection
Sato, Motoyuki ; Fujiwara, Jun ; Feng, Xuan ; Zhou, Zheng-Shu ; Kobayashi, Takao ;
Geophysics and Geophysical Exploration, volume 8, issue 4, 2005, Pages 270~279
Under the research project supported by Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT), we have conducted the development of GPR systems for landmine detection. Until 2005, we have finished development of two prototype GPR systems, namely ALIS (Advanced Landmine Imaging System) and SAR-GPR (Synthetic Aperture Radar-Ground Penetrating Radar). ALIS is a novel landmine detection sensor system combined with a metal detector and GPR. This is a hand-held equipment, which has a sensor position tracking system, and can visualize the sensor output in real time. In order to achieve the sensor tracking system, ALIS needs only one CCD camera attached on the sensor handle. The CCD image is superimposed with the GPR and metal detector signal, and the detection and identification of buried targets is quite easy and reliable. Field evaluation test of ALIS was conducted in December 2004 in Afghanistan, and we demonstrated that it can detect buried antipersonnel landmines, and can also discriminate metal fragments from landmines. SAR-GPR (Synthetic Aperture Radar-Ground Penetrating Radar) is a machine mounted sensor system composed of B GPR and a metal detector. The GPR employs an array antenna for advanced signal processing for better subsurface imaging. SAR-GPR combined with synthetic aperture radar algorithm, can suppress clutter and can image buried objects in strongly inhomogeneous material. SAR-GPR is a stepped frequency radar system, whose RF component is a newly developed compact vector network analyzers. The size of the system is 30cm x 30cm x 30 cm, composed from six Vivaldi antennas and three vector network analyzers. The weight of the system is 17 kg, and it can be mounted on a robotic arm on a small unmanned vehicle. The field test of this system was carried out in March 2005 in Japan.
Time-lapse Geophysical Monitoring of
Kim, Hee-Joon ; Choi, Ji-Hyang ; Han, Nu-Ree ; Nam, Myung-Jin ; Song, Yoon-Ho ; Lee, Tae-Jong ; Suh, Jung-Hee ;
Geophysics and Geophysical Exploration, volume 8, issue 4, 2005, Pages 280~286
Geological sequestration of carbon dioxide (
) is one of the most effective strategies far long-term removal of greenhouse gas from atmosphere. This paper reviews three projects for the
sequestration in geological formation. A unique
injection into a marine aquifer has been successfully monitored with repeated surface seismic measurements in the North Sea Sleipner West field. The seismic images reveal the extent and internal shape of the
bubble. Massive miscible
has been injected into a complex fractured carbonate reservoir at the Weyburn oil filed. High-resolution time-lapse P-wave data were successfully obtained to map the features of
movements within the two thin zones of different lithology. From the time-lapse crosswell EM imaging at the Lost Hills oil field in central California, U.S.A., the replacement of brine with
has been confirmed through a decrease of conductivity. The conductivity image was successfully compared with induction logs observed in the two wells.