• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2000년도 추계학술대회
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• pp.258-261
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• 2000

Geophysical surveys (electrical resistivity, self-potential, and magnetic methods) and streamwater sample analysis have been carried out at a site of tailings of waste deposits in an abandoned mine, Jangpoong, which is situated in Kowesan-Gun, Chungbuk-Do. The research was aimed at investigating the suitability of the various geophysical methods for detection of AMD (acid mine drainage) paths, and ultimately mapping of preferred AMD flow channels by incorporating the water sample analysis. Electrical resistivity section from the dipole-dipole line represents the low-resistivity zone trending northwest toward the stream nearby. The positions of the resistivity anomalies for AMD channels are well correlated to the ones from the various geophysical surveys. In addition they correspond to the sites of the higher peaks for the pH, EC, heavy metal content for the water sample data.

• 대한원격탐사학회지
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• 제21권1호
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• pp.3-13
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• 2005

National Research Lab Project 'Optimal Data Fusion of Geophysical and Geodetic Measurements for Geological Hazards Monitoring and Prediction' supported by Korea Ministry of Science and Technology is briefly described. The research focused on the geohazard analysis with geophysical and geodetic instruments such as superconducting gravimeter, seismometer, magnetometer, GPS, and Synthetic Aperture Radar. The aim of the NRL research is to verify the causes of geological hazards through optimal fusion of various observational data in three phases: surface data fusion using geodetic measurements; subsurface data fusion using geophysical measurements; and, finally fusion of both geodetic and geophysical data. The NRL hosted a special session 'Geohazard Monitoring with Space and Geophysical Technology' during the International Symposium on Remote Sensing in 2004 to discuss the current topics, challenges and possible directions in the geohazard research. Here, we briefly describe the special session papers and their relationships to the theme of the special session. The fusion of satellite and ground geophysical and geodetic data gives us new insight on the monitoring and prediction of the geological hazard.

• 지구물리와물리탐사
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• 제7권1호
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• pp.99-104
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• 2004

A combination of drilling, geophysical well logging, and electrical soundings was performed to evaluate seawater intrusion in Baeksu-eup, Youngkwang-gun, Korea. The survey area extends for over 24 $km^2$. To delineate the extent of seawater intrusion, 60 vertical electrical soundings (VES) have been carried out. Twelve wells were also drilled for the collection of hydrogeological, geochemical, and geophysical well logging data, to delineate the degree and vertical extent of seawater intrusion. To map the spatial distribution of seawater in this coastal aquifer, geophysical data and hydrogeochemical results were used, and the relation between the resistivity of groundwater and equivalent NaCl concentration was found. Layer parameters derived from VES data, various in-situ physical properties from geophysical well logging, and the estimated equivalent NaCl concentration were very useful for quantitative evaluation of seawater intrusion. Our approach for evaluating seawater intrusion can be considered a valuable attempt at enhancing the use of geophysical data.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
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• pp.455-458
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• 2003

A combination of drilling, hydrogeochemical survey, geophysical survey and the numerical modelling for the flow and transport of groundwater was performed to evaluate the seawater intrusion in Baeksu-eup, Yeonggwang-gun, Korea. The survey area extends to over 24 $km^2$. Twelve wells were also drilled for the collection of geologic, geochemical, hydrologic, and geophysical logging data to delineate the degree and vertical extent of seawater intrusion. To evaluate and map the salinity in a coastal aquifer, geophysical data and hydrogeochemical results were used. Layer parameters derived from VES data, various in situ physical properties from geophysical well loggings, and the estimated equivalent NaCl concentration were used as the useful input parameters for the numerical simulation with density-dependent flow. Our multidisciplinary approach for evaluating the seawater intrusion can be considered as a valuable attempt to enhancing the utilization of various data and the reliability of numerical ground modelling.

• 산업기술연구
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• 제27권B호
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• pp.115-119
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• 2007

Currently, geophysical method is applied for understanding the subsurface geologic structure economically and systematically, but there exists some limitations on recognizing complex subsurface structures precisely by a single geophysical method. In order to understand the complex subsurface structures, we applied various geophysical methods including seismic refraction survey, two-dimensional resistivity survey, seismic tomography survey, suspension-ps log, and understood distribution of low velocity, low resistivity range of resistivity survey and correlation of an intersecting point, velocity distribution of seismic tomography survey.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
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• pp.340-343
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• 2003

This study presents a practical procedure for the Bayesian inversion of geophysical data by Markov chain Monte Carlo (MCMC) sampling and geostatistics. We have applied geostatistical techniques for the acquisition of prior model information, and then the MCMC method was adopted to infer the characteristics of the marginal distributions of model parameters. For the Bayesian inversion of dipole-dipole array resistivity data, we have used the indicator kriging and simulation techniques to generate cumulative density functions from Schlumberger array resistivity data and well logging data, and obtained prior information by cokriging and simulations from covariogram models. The indicator approach makes it possible to incorporate non-parametric information into the probabilistic density function. We have also adopted the MCMC approach, based on Gibbs sampling, to examine the characteristics of a posteriori probability density function and the marginal distribution of each parameter. This approach provides an effective way to treat Bayesian inversion of geophysical data and reduce the non-uniqueness by incorporating various prior information.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2000년도 추계학술대회
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• pp.103-106
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• 2000

Geophysical data sets from the Chojeong area in the Chungbuk-Do are compositely studied in terms of multi-attribute interpretation for the subsurface mapping of shallow fracture zones, associated with groundwater reservoir. Utilizing a GIS software, the attribute data are implemented to a database; a lineament from the satellite image, electrical resistivities and its standard deviation, radioactivity, seismic velocity, bedrock depth from exploration data. In an attempt to interpret 1-D electrical sounding data in 2-D and 3-D views, 2-D resistivities structures are firstly made by interpolating 1-D plots. Reconstruction of a resistivity volume is found to be an effective scheme for subsurface mapping of shallow fracture zones. Shallow fracture zones in the southeastern part of the study area are commonly correlated in the various exploration data.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2007년도 공동학술대회 논문집
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• pp.48-53
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• 2007

A new way to integrate various geophysical information for evaluation of RQD was developed. In this study, we did not directly define the RQD value where borehole data are not sampled. Instead, we infer the probability of RQD values with prior probability from borehole direct data, and secondary supporting probability from resistivity and seismic tomography data. For the integration, we applied the geostatstical indicator kriging to get prior probability of RQD value, and indicator kriging with soft data to get the supporting probability from resistivity and seismic data. And we finally use the permanence ratio rule to integrate these information. The finally obtained result was also analyzed to fully utilize the probabilistic features. We show the probability of wrongly classifying the RQD evaluation and vice versa. This result may be used for decision making process based on the geophysical exploration.

• 자원환경지질
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• 제33권4호
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• pp.283-293
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• 2000

A set of geophysical survey results over an area in Bookil-myun, Chungwon-Gun, Chungcheongbuk-Do is presented; resistivity logging, d.c. sounding, dipole-dipole resistivity, and controlled-source magnetotelluric (CSMT) surveys. These surveys were chosen in this research for the estimation of the basement depth and the delineation of the hydrogeologic structure over the survey area. The results provide an optimal input to a hydrogeologic modeling analysis using the strategies built in GIS software. A total of 14 lines of dipole-dipole resistivity surveys, 25 stations of d.c. sounding and 6 stations of CSMT sounding were performed. In addition 10 boreholes were chosen for resistivity logging to correlate the logs to the surface data. A quantitative information on the hydrogeologic structure over the area is provided by synthesizing the results from various geophysical data and attribute layers are constructed by utilizing a GIS software Arc/ Info. The constructed layers match well to the hydrogeologic structures, which were outlined from the drilling data. The methodology tested and adopted in this study would be useful for providing a more reliable input to the hydrogeologic model setup.

• 지구물리와물리탐사
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• 제15권4호
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• pp.177-189
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• 2012

복합 물리탐사(전기비저항, MT)와 지질(시추 자료 및 코어 물성)정보에 대해 지구통계학적 복합해석 기법을 적용하여 3차원 광체 모델링 평가를 수행하였다. 우선, 복합 물리탐사를 통해 시추공 및 그 외의 전체적인 지역에 대한 비저항대 분포를 파악할 수 있었으며, 코어 물성 시험을 통해 연구지역의 자철석(광체)이 코어 내부의 밀도가 높은 전도성 성분(Fe)에 의해 밀도의 증가에 따라 비저항이 감소하는 상관관계를 나타냄을 파악하였다. 3차원 광체 모델링을 수행하기 위해 사용된 자료는 전기비저항 탐사, MT 탐사, 물성 자료와 시추 자료 등이며, 전체 획득 자료 및 시추 자료에서 추출한 광체의 품위 자료를 이용하였다. 본 연구에서는 자료의 복합 해석을 위해 지구통계학적 기법 중에서, 부족한 실제 측정 자료의 평균 및 분산을 잘 재생시키는 실현 값을 통해 지역적으로 변화하는 불균질성을 잘 묘사하는 순차 가우시안 시뮬레이션(sequential Gaussian simulation)을 사용하였다. 획득된 전체 자료와 품위 자료만을 이용하여 도출한 시뮬레이션 결과, 광체가 기존에 연구되어 존재하는 잔광체의 일정 부분에서 유사한 분포를 나타냈으며, 추가적으로 하부 깊은 심도에 대해 광체의 분포 양상을 추정할 수 있었다.