• Title/Summary/Keyword: 전기탐사

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A Study on the Correlation Between Electrical Resistivity and Rock Classification (전기비저항과 암반분류의 상관관계에 대한 고찰)

  • Kwon, Hyoung-Seok;Hwang, Se-Ho;Baek, Hwan-Jo;Kim, Ki-Seog
    • Geophysics and Geophysical Exploration
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    • v.11 no.4
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    • pp.350-360
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    • 2008
  • Electrical resistivity is one of physical property of the earth and measured by electrical resistivity survey, electrical resistivity logging and laboratory test. Recently, electrical resistivity is widely used in determination of rock quality in support pattern design of road and railway tunnel construction sites. To get more reliable rock quality data from electrical resistivity, it needs a lot of test and study on correlation of resistivity and rock quality. Firstly, we did rock property test in laboratory, such as P wave velocity, Young's modulus, uniaxial compressive strength (UCS) and electrical resistivity. We correlate each test results and we found out that electrical resistivity has highly related to P wave velocity, Young's modulus and UCS. Next, we accomplished electrical resistivity survey in field site and carried out electrical resistivity logging at in-situ area. We also performed rock classification, such as RQD, RMR and Q-system and we correlate electrical resistivity to RMR data. We found out that electrical resistivity logging data are highly correlate to RMR. Also we found out that electrical resistivity survey data are lower than electrical resistivity logging data when there are faults or fractures. And it cause electrical resistivity survey data to lowly correlate to RMR.

Analysis for Reclaimed Cultural Asset Location Estimation with Complex Seismic Survey (복합지구물리탐사에 의한 매립 문화재 위치 추정 분석)

  • Jang, Ho-Sik;Roh, Tae-Ho
    • The Journal of the Korea Contents Association
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    • v.12 no.8
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    • pp.380-387
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    • 2012
  • A complex seismic survey, which is nondestructive inspection, is used often recently in estimating the location of reclaimed cultural assets. Such a method is the best way to estimate the location of cultural assets most effectively in a short time at a construction site. This study estimated the reclamation location of a cultural asset by using magnetic gradient survey, earth resistivity survey, and ground penetrating radar survey (GPR) in order to figure out the distribution territory in the area with possibility of creation of reclaimed cultural assets in the past. As a result, it was located at +15m on the X axis and +90m on the Y axis on the floor plane coordinate of the study target area. It was shown that the major axis is about 20m long in the north-northeast direction and the width is about 5m. The depth of development distribution of anomaly zone was estimated as about 1.5~3.0m. Geophysical survey is expected to be used as a efficient and accurate way to excavate the reclaimed cultural assets in future.

Industry-University-Research Collaborative Geoscientific Study in Pocheon Area for Groundwater Survey, Part III : Resistivity Technology (포천지역 지하수기초조사 산학연 공동탐사 사례연구(III): 전기탐사기술)

  • You, Young-June;Kim, Jong-Nam;Yoo, In-Kol
    • 한국지구물리탐사학회:학술대회논문집
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    • 2005.05a
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    • pp.129-136
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    • 2005
  • The groundwater survey was carried out by electrical resistivity and resistivity tomography using several kinds of electrode array to delineate the depth of the saturated zone and basement complex, the aquifer system of fractured rock, and the 2-D resistivity structure was obtained by inversion technique. And the hole-to-surface and crosshole tomography were applied for two boreholes and the inverted resistivity tomogram are obtained. The comparison of those data with core logging data was performed and those results were relatively well correlated. And it was possible to find out the configuration of basement and the fracture zone and the aquifer system from the 2-D resistivity structure and resistivity tomogram.

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A Feasibility Study of AMT Application to Tidal Flat Sedimentary Layer (갯벌 지역의 하부퇴적층에 대한 AMT 탐사의 적용 가능성 평가)

  • Kwon, Byung-Doo;Lee, Choon-Ki;Park, Gye-Soon;Choi, Su-Young;Yoo, Hee-Young;Choi, Jong-Keun;Eom, Joo-Young
    • Journal of the Korean earth science society
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    • v.28 no.1
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    • pp.64-74
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    • 2007
  • The marine seismic prospecting using a research vessel in the shallow sea near the coastal area has certain limits according to the water depth and survey environment. Also, for the electrical resistivity survey at seashore area, one may need a specially designed high-voltage source to penetrate the very conductive surface layer. Therefore, we have conducted a feasibility study on the application of magnetotelluric method (MT), a passive geophysical method, on investigating of shallow marine environment geology. Our study involves both theoretical modeling and field survey at the tidal flat area which represent the very shallow marine environment. We have applied the audio-frequency magnetotelluric (AMT) method to the intertidal deposits of Gunhung Bay, west coast of Korea, and analysed the field data both qualitatively and quantitatively to investigate the morphology and sedimentary stratigraphy of the tidal flat. The inversion of AMT data well reveals the upper sedimentary layer of Holocene intertidal sediments having a range of 13-20 m thickness and the erosional patterns at the unconformable contact boundary. However, the AMT inversion results tend to overestimate the depth of basement (30-50 m) when compared with the seismic section (27-33 m). Since MT responses are not significantly sensitive to the resistivity of middle layer or the depth of basement, the AMT inversion result for basement may have to be adjusted using the comparison with other geophysical information like seismic section or logging data if possible. But, the AMT method can be an effective alternative choice for investigating the seashore area to get important basic informations such as the depositional environment of the tidal flat, sea-water intrusion and the basement structure near the sea shore.

Shallow Eelectrical Resistivity and VLF Profiling at Sangchon-ri Area along the Southern Par of Yangsan Fault (양산단층 남부 상천리 일대의 천부 전기비저항 및 VLF 탐사)

  • 경재복;한수형;조현주;김지수
    • The Journal of Engineering Geology
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    • v.9 no.1
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    • pp.59-68
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    • 1999
  • To clarify the geological structure of Yangsan fault around Sangchon-ri in the southern part of Kyungsang Basin the resistivity (dipole-dipole profiling) and VLF surveys carried out on the four profiles, crossing the inferred trace of the fault. The resistivity contrast across the fault is clearly shown on the profiles: higher resistivity and lower resistivity on the east and west, respectively. It is most likely from the uplift of the granitic bedrock on the east park due to the strike-fault raulting with vertical movement. The zero-crossing points of VLF anomalies, associated with near-surface fracture zone, are found to well correlate with the resistivity boundaries from the dipole-dipole profiling. Consequently, southern segment of Yangsan fault (at Sangchon-ri area) is interpreted to be vertically developed strike-slip fault with a difference more than 10m depth of basement rock at both sides.

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Interpretation of Vertical Electrical Sounding Data in Saltwater Intrusion Area using Geostatistical Method (지구통계분석을 이용한 해수침투지역에서의 전기비저항탐사 자료 해석)

  • Song Sung-Ho;Lee Gyu-Sang;Yong Hwan-Ho;Kim Jin-Sung;Seong Baek-Uk;Woo Myung-Ha
    • 한국지구물리탐사학회:학술대회논문집
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    • 2005.05a
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    • pp.59-64
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    • 2005
  • Although experimental analysis for groundwater sample at wells located systematically are very effective to delineate seawater intrusion region at coastal area, this method is restricted in few wells and time. We have conducted electrical resistivity sounding at 30 points in the study areas to analyze the region of seawater intrusion and found the boundary between salt wedge and fresh water lens from the analysis results of geostatistical method using variogram for one-dimensional inversion results. The methodology adopted in this study would be useful for finding the seawater intrusion region and evaluating quantitatively.

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