• Title/Summary/Keyword: geophysical data

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Case of Geophysical Survey Guideline for Site Investigation of Spent Nuclear Fuel disposal: Focusing on airborne electromagnetic and seismic reflection survey (사용후핵연료 처분시설 부지조사를 위한 물리탐사 수행지침서 작성 사례 : 항공전자탐사와 탄성파 반사법탐사 중심으로)

  • NamYoung Kong;Hagsoo Kim;Yoonsup Moon;Manho Han
    • Geophysics and Geophysical Exploration
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    • v.27 no.1
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    • pp.69-83
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    • 2024
  • Considering importance and specificity, site investigations for deep geological disposal of Spent Nuclear Fuel require stringent quality control, unlike general geotechnical investigations for tunnels and bridges. In this study, we present a case of selecting geophysical survey method for individual site investigation stage and preparing geophysical survey guideline. The proposed geophysical survey guidelines include procedures, considerations, and quality control for exploration planning, data acquisition, data processing, and interpretation. They comprehensively summarize the contents of airborne electromagnetic survey and seismic reflection survey.

Archaeological Investigations in Urban Areas through Combined Application of Surface ERT and GPR Techniques

  • Papadopoulos, Nikos;Yi, Myeong-Jong;Sarris, Apostolos;Kim, Jung-Ho
    • 한국지구물리탐사학회:학술대회논문집
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    • 2008.10a
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    • pp.113-118
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    • 2008
  • Among the geophysical methods, Ground Penetrating Radar (GPR) and Electrical Resistivity Tomography (ERT) comprise the most promising techniques in resolving buried archaeological structures in urban territories. In this work, two case studies which involve an integrated geophysical survey employing the surface three dimensional (3D) ERT and GPR techniques, in order to archaeologically characterize the investigated areas, are presented. Totally more than 4000 square meters were investigated from the test field sites, which are located at the centre of two of the most populated cities of the island of Crete, in Greece. The ERT and the GPR data were collected along dense and parallel profiles. The subsurface resistivity structure was reconstructed by processing the apparent resistivity data with a 3D inversion algorithm. The GPR sections were processed with a systematic way applying specific filters to the data in order to enhance their information context. Finally, horizontal depth slices representing the 3D variation of the physical properties were created and the geophysical anomalies were interpreted in terms of possible archaeological structures. The subsequent excavations in one of the sites verified the geophysical results, enhancing the applicability of ERT and GPR techniques in the archaeological exploration of urban territories.

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Study on Analysis of Geophysical Data for Complex Geological Condition (복잡한 지하구조 해석을 위한 물리탐사 자료 분석에 관한 연구)

  • Shin, Deuck-Hyun;Kim, Hoon;Oh, Seok-Hoon;Suh, Baek-soo
    • Journal of Industrial Technology
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    • v.27 no.B
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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.

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RMR Evaluation by Integration of Geophysical and Borehole Data using Non-linear Indicator Transform and 3D Kriging (암반등급 해석을 위한 비선형 지시자 변환과 3차원 크리깅 기술의 물리탐사 및 시추자료에 대한 적용)

  • Oh, Seo-Khoon
    • Journal of the Korean earth science society
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    • v.26 no.5
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    • pp.429-435
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    • 2005
  • 3D RMR (Rock Mass Rating) analysis has been performed by applying the Geostatistical integration technique for geophysical and borehole data. Of the various geostatistical techniques for the integrated data analysis, in this study, we applied the SKlvm (Simple Kriging with local varying means) method that substitutes the values of the interpreted geophysical result with the mean values of the RMR at the location to be inferred. The substitution is performed by the indicator transform between the result of geophysical interpretation and the observed RMR values at borehole sites. The used geophysical data are the electrical resistivity and MT result, and 10 borehole sites are investigated to obtain the RMR values. This integrated analysis makes the interpretation to be more practical for identifying the realistic RMR distribution that supports the regional geological situation.

Application of geophysical well logging to fracture identification and determination of in-situ dynamic elastic constants. (물리검층에 의한 파쇄대 인식과 동적 지반정수의 산출)

  • Hwang, Se-Ho;Lee, Sang-Kyu
    • 한국지구물리탐사학회:학술대회논문집
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    • 1999.08a
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    • pp.156-175
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    • 1999
  • Recently the application of geophysical well logging to geotechnical site investigation is increasing, because the merit that geophysical logs provide the high resolution and in-situ physical properties in volumes of rock surrounding the borehole. Geophysical well logs are used to identify lithologic boundaries and fracture, to determine the physical properties of rock(i.e., density, velocity etc.), and to detect permeable fracture zones that could be conduits for ground water movement through the rocks. The principle of heat-pulse meter, the calibration of gamma-gamma logging, and principles and data processing of full waveform sonic logging are briefly reviewed, and the case studies of geophysical logs are discussed. Correlation between velocity by sonic logging and rock mass classification such as RMR(Rock Mass Rating) value is considered.

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Geostatistics for Bayesian interpretation of geophysical data

  • Oh Seokhoon;Lee Duk Kee;Yang Junmo;Youn Yong-Hoon
    • 한국지구물리탐사학회:학술대회논문집
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    • 2003.11a
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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.

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Geophysical Surveys for Investigating the Groundwater Environment of the Chojeong, Chungbuk (충북 초정지역의 지하수환경 조사를 위한 지표지구물리탐사)

  • 김지수;한수형;김경호;신재우
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2000.11a
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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.

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Integrated Interpretation of Geophysical Data and its Application by Geostatistical Approach (지구통계학적 방식에 의한 물리탐사 자료의 복합해석과 그 응용)

  • Oh, Seok-Hoon;Chung, Ho-Joon;Suh, Baek-Soo
    • 한국지구물리탐사학회:학술대회논문집
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    • 2007.06a
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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.

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균열암반 물리검층 자료의 수리지질특성에 대한 다변량 통계분석

  • 고경석;황세호;이진수;김용제;김태희
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2004.09a
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    • pp.373-376
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    • 2004
  • To investigate the vertical petrological and hydrological characteristics of fractured rock, geophysical and chemical logging were executed at 5 boreholes installed in the study area. The geophysical and hydrochemical logging data were analysed by using principal components analysis (PCA). Three main variables from PCA explained 86.4% of total variance of geophysical log data. The PCA results showed that PCl is closely related to groundwater properties and PC2 and PC3 are influenced by rock and fracture properties. Hydrochemical analysis indicated the presence of highly fractrued zone at the depth of 60m.

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An integrated studies for salt-water intrusion in Yeonggwang-gun, Korea

  • Hwang Seho;Chi Sejung;Lee Won-suk;Shin Jehyun;Park Inhwa;Huh Dae-Gee;Lee Sang-kyu
    • 한국지구물리탐사학회:학술대회논문집
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    • 2003.11a
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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.

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