• Title, Summary, Keyword: geophysical exploration

Search Result 1,128, Processing Time 0.049 seconds

Geophysical exploration techniques, used in geotechnical and engineering markets in Korea, Japan, and U.S.A. (지반환경조사에 주로 사용되는 지구물리탐사기법 -한국, 일본, 미국-)

  • Won, Kyung-Sik
    • Journal of the Korean Geophysical Society
    • /
    • v.5 no.3
    • /
    • pp.247-268
    • /
    • 2002
  • The various geophysical exploration techniques, which are currently employed in Korea, are investigated in terms of the survey specifications used in the geotechnical and engineeringl markets in Korea, Japan, and USA.

  • PDF

Study of Stability Analysis and Countermeasure Tunnel Portal Failure using Dipole-Dipole Investigation (쌍극자(Dipole-Dipole)탐사를 활용한 터널붕괴사면 조사 및 대책방안 제시 연구)

  • Baek, Yong;Rhee, Jong-Hyun;Koo, Ho-Bon;Bae, Gyu-Jin
    • Proceedings of the Korean Geotechical Society Conference
    • /
    • /
    • pp.493-498
    • /
    • 2003
  • In case of slope failure by planted protection is constructed on the slope according to of the choice trend of a recently environmental-friendly countermeasure, there has a limitation about diagnosis and preparation of measure. Also, collapse of tunnel pithead department slope has maximum in construction and countermeasure method of construction choice unlike cut-slope. In this study, analyzed inside circumstance of slope using geophysical exploration for stability analysis and countermeasure inside presentation of tunnel pithead department slope which collapse happens. geophysical exploration used dipole(Dipole-Dipole) method that is based to distribution principle does specific resistance, goes side by side with on-the-spot observation and draws base strength parameter and executed stability analysis, and presented stabilization countermeasure inside of collapse slope on this. I wish to conduce in development and research for use technical development of geophysical exploration technique hereafter by executing geophysical exploration in road collapse spot applying through this study.

  • PDF

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
    • /
    • /
    • pp.156-175
    • /
    • 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.

  • PDF

A Study on the Modified Electrode Arrays in Two-Dimensional Resistivity Survey (2차원 전기비저항 탐사를 위한 변형된 전극배열법에 관한 연구)

  • Kim Jung-Ho;Yi Myeong-Jong;Song Yoonho;Chung Seung-Hwan
    • Geophysics and Geophysical Exploration
    • /
    • v.4 no.3
    • /
    • pp.59-69
    • /
    • 2001
  • Five kinds of modified electrode arrays were proposed to overcome the weak points of the commonly used arrays using dipole and/or pole in two-dimensional resistivity surveys. The modified pole-pole array was suggested to overcome the inefficiency caused by distant earthing in pole-pole array. Four kinds of modified arrays using dipole were designed to enhance the signal-to-noise ratio of the conventional dipole-dipole and pole-dipole arrays through boosting up the measured potential difference. In the numerical experiments using the two-dimensional modeling and inversion, the effects of the ambient electrical noise and the resolving power were examined and the results showed the validity of the modified arrays proposed in this study.

  • PDF

Current Status and Perspectives of Korean Geophysics (우리나라 지구물리학의 현황과 미래 전망)

  • Kwon, Byung-Doo
    • 한국지구물리탐사학회:학술대회논문집
    • /
    • /
    • pp.1-14
    • /
    • 2007
  • This paper briefly reviews the history of the Korean geophysics and analyze the current status of geophysical researches. And the future prospects of geophysics are discussed based on social demands for the science and technology in Korea. About thirty universities offer geophysics courses in their academic curricula. Although the number of Ph.D. graduates in geophysics had been small until the year of 1990, but is rapidly increasing. In recent years about $7{\sim}8$ Ph.D's are produced every year. The major geophysical methods used in Ph.D. theses are seismic, electrical and electromagnetic methods, and earthquake waves and research themes are computational geophysics, which involve data processing, modelling, inversion and tomography, geological structures, and paleomagnetic studies in the order of numbers. The Solid Earth Geophysics is generally distinguished in two categories such as "Global Geophysics" and "Exploration Geophysics". However, they are intimately connected, and overlap in many sectors, especially in large scale research projects. The global geophysics has a more academic and general scientific meaning, and several research groups in Korean universities are carrying out the earthquake seismology and paleomagnetic studies. On the other hand the exploration geophysics focuses on practical application of geophysical concepts, and the public research institutes conduct large projects for exploration of energy and mineral resources and to cope with environmental and natural disaster problems. The geophysical studies for local geology and regional crustal structure utilize various survey methods and usually cover both academic and exploration purposes. The computational geophysics constitutes the indispensable theoretical backgrounds for all geophysical sectors. Many young Korean geophysicists, who have strong background in mathematics and physics, devote to the computational geophysics and several groups have made the internationally highest level achievements. But, Korean geophysicists have to expand their research interests to include more global-scale, high-tech researches and collaborative works with various other science groups.

  • PDF

Two-dimensional Modeling and Inversion of MT Data Including Topography (지형을 포함한 MT 탐사 자료의 2차원 모델링과 역산)

  • Lee Seong Kon;Song Yoonho;Kim Jung-Ho;Chung Seung-Hwan
    • Geophysics and Geophysical Exploration
    • /
    • v.5 no.4
    • /
    • pp.291-298
    • /
    • 2002
  • We have developed a two-dimensional (2-D) magnetotelluric (MT) inversion algorithm, which can include topographic effects in inversion. We use the finite element method (FEM) to incorporate topography into forward calculation. Topography is implemented simply by moving nodes of rectangular elements in z-direction according to the elevation of air-earth interface. In the inversion process, we adopt a spatially variable Lagrangian multiplier algorithm in the smoothness-constrained least-squares inversion. The inversion algorithm developed in this study reconstructs subsurface resistivity structure quite well when topography variation exists. Also, it turns out to be effective in both resolution and stability from a model study and field data application.

A Breakthrough in Sensing and Measurement Technologies: Compressed Sensing and Super-Resolution for Geophysical Exploration (센싱 및 계측 기술에서의 혁신: 지구물리 탐사를 위한 압축센싱 및 초고해상도 기술)

  • Kong, Seung-Hyun;Han, Seung-Jun
    • Geophysics and Geophysical Exploration
    • /
    • v.14 no.4
    • /
    • pp.335-341
    • /
    • 2011
  • Most sensing and instrumentation systems should have very higher sampling rate than required data rate not to miss important information. This means that the system can be inefficient in some cases. This paper introduces two new research areas about information acquisition with high accuracy from less number of sampled data. One is Compressed Sensing technology (which obtains original information with as little samples as possible) and the other is Super-Resolution technology (which gains very high-resolution information from restrictively sampled data). This paper explains fundamental theories and reconstruction algorithms of compressed sensing technology and describes several applications to geophysical exploration. In addition, this paper explains the fundamentals of super-resolution technology and introduces recent research results and its applications, e.g. FRI (Finite Rate of Innovation) and LIMS (Least-squares based Iterative Multipath Super-resolution). In conclusion, this paper discusses how these technologies can be used in geophysical exploration systems.

Applicability of Geophyscal Well Logging in the Assessment of Seawater Intrusion (임해지역 해수침투 평가를 위한 물리검층의 적용성)

  • Lee Sang-Gyu;Hwang Sae-Ho;Hwang Hak-Su;Park In-Hwa
    • Geophysics and Geophysical Exploration
    • /
    • v.3 no.3
    • /
    • pp.101-111
    • /
    • 2000
  • In order to assess the seawater intrusion, induction, temperature and conductivity of fluid, and natural gamma logs were obtained in nine wells at the three study areas having different hydrogeologic characteristics. Besides surface geophysical exploration, supplementary geophysical well logs were carried out to understand the hydrogeological characteristics related to the seawater intrusion in the study areas. The geophysical well logs have been proved to increase the accuracy of interpretation of the surface geophyscial exploration's data for assessment of seawater intrusion, and to get the optimum depth for a long monitoring of groundwater. They, also, revealed that the identification of hydrogeological units for strata's porosity was able to be achieved and were illustrated the applicability of geophysical well logs monitoring. Finally, geophysical well logs are expected to play to get the more quantitative information of seawater infusion, if it is fully collaborated with a better method that is strata's resistivity determination with not relatively much effected by seawater within the drilled borehole and that is the porosity measurement with built on small diameter PVC casing.

  • PDF

Achievements and Tasks of Korea-Japan Geophysical Exploration through Burial mounds Exploration (고분 탐사를 통해 본 한·일 물리탐사의 성과와 과제)

  • Shin, Jong woo
    • MUNHWAJAE Korean Journal of Cultural Heritage Studies
    • /
    • v.48 no.4
    • /
    • pp.74-93
    • /
    • 2015
  • Geophysical survey of Korea was introduced in Nara National Research Institute of Cultural Heritage in 1995. At that time, it has been activated geophysical survey of architecture and civil engineering in Korea. But there was no exploration experts to be combined the archaeology. For this reason, National Research Institute of Cultural Heritage has introduced the physical exploration. Through the expert exchanges South Korea and Japan carried out joint exploration. And it has increased the reliability of the exploration method and exploration results. It is GPR the most method commonly in geophysical exploration. There are many usability before excavation because of good resolution. However, the shallow GPR penetration depth has limitations in large mounds. We were able to take advantage of the resistivity analysis program to study the underground structure to deep through the experts exchange. We was able to get a good result that overcomes the limitations of GPR exploration in a number of burial mounds including Naju bokamri by the resistivity analysis program. In particular, we confirmed the location of the burial main body by compares the results of exploration and excavation results. In the future we will perform a convergence research of exploration and archaeology through a variety of joint research. In addition we will have to build a new network of archaeological science.