• Title/Summary/Keyword: Geophysical exploration

Search Result 1,216, Processing Time 0.028 seconds

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

  • Shin, Jong woo
    • Korean Journal of Heritage: History & Science
    • /
    • 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.

THE STATUS QUO OF THE GEOMAGNETIC FIELD MEASUREMENTS IN KOREA (한국에서의 지구자기장관측의 현황)

  • LIM MU-TAEK;PARK YEONG-SUE;JUNG HYUN-KEY;LEE HEE-IL
    • Publications of The Korean Astronomical Society
    • /
    • v.15 no.spc2
    • /
    • pp.15-20
    • /
    • 2000
  • The geomagnetic measurements on the Korean Territory began in 1918 in the Incheon (Zinsen in Japanese pronunciation) Observatory of which the annual means of total magnetic field intensity, declination, and inclination still remain for 1918-1944. From 1970s, the National Geography Institute (NGI) and the Radio Research Laboratory (RRL) have tried independently to measure the geomagnetic field continuously. The RRL as the result of such efforts has installed 3 geomagnetic observatories, the first in Icheon and the second in Yongin in 1996, and the third in Jeju in 1997. From 1992, the Korea Institute of Geology, Mining and Materials (KIGAM) has tried also to measure the geomagnetism and as the result they have installed 2 geomagnetic observatories, one in Daejeon in 1998 and the other in Gyeongju in 2000. Nowadays, the RRL and the KIGAM collect the measured data into their own main computers by telecommunication in real time. The two institutions will cooperate in near future to link the two geomagnetic data bases so that the whole set of geomagnetic data measured on Korean Territory could be provided to the end users in Korea.

  • PDF

Time-lapse Geophysical Survey Analysis for Field-scale Test bed of Excavation Construction (실규모 굴착 시험장에서의 시간경과 물리탐사 자료 분석)

  • Shin, Dong Keun;Song, Seo Young;Kim, Bitnarae;Yoo, Huieun;Ki, Jung Seck;Nam, Myung Jin
    • The Journal of Engineering Geology
    • /
    • v.29 no.2
    • /
    • pp.137-151
    • /
    • 2019
  • Geophysical exploration techniques are effective for monitoring changes in the ground condition around the excavation project to prevent subsidence risks during excavation work, therefore, improving analysis techniques is required for applying and supplementing various geophysical exploration technologies. In this study, a field-scale on-site test was conducted to detect possible ground subsidence hazards and areas of relaxation zone that may occur during excavation work and due to underground water level changes. In order to carry out the field test, a real-scale excavation test bed was constructed and the geophysical exploration methods, such as electrical resistivity survey and multi-channel analysis of surface wave (MASW) survey for urban sites condition, have researched for optimal geophysical exploration parameter, design and correlation analysis between the results by reviewing the validity of each individual geophysical exploration and modeling. The results of this study showed the impact of each geophysical exploration on the relaxation zone and, in particular, the location of the underground water surface and the effects of excavation were identified using electrical resistivity survey. Further research on modeling will be required, taking into account the effects of excavation and groundwater.

The State-of-the-Art of Geophysical Exploration Technology applied to Site Characterization in Civil Engineering and Construction in Japan (일본에서의 토목${\cdot}$건설 지반조사를 위한 물리탐사 활용 현황)

  • Park, Sam-Gyu;Kim, Hee-Joon
    • 한국지구물리탐사학회:학술대회논문집
    • /
    • 1999.08a
    • /
    • pp.1-20
    • /
    • 1999
  • In Japan, geophysical exploration methods have been widely applied to civil engineering and construction fields for a long time. In particular, seismic refraction has long played a significant role in geotechnical site investigations for tunnels, dams and landslides. However, our growing interest on the social and natural environment makes the methods available and its application fields diversify. Digital technologies such as personal computer have revolutionized our ability to acquire large volumes of data rapidly, and to produce more reliable results for subsurface image. Also, color graphics easily visualizes survey results In a more understandable manner, These days geophysical methods are essential to assessing grouting effects, predicting the front of tunnel cutting face, monitoring the movement, pollution and purification process of groundwater. Now three-dimensional exploration techniques have developed for the site characterization in civil engineering and construction needs.

  • PDF

A Study on the Development of Multifuntional Real-Time Inclination and Azimuth Measurement System (다용도 실시간 경사각과 방위각 연속 측정 시스템 개발연구)

  • Kim, Gyuhyun;Cho, Sung-Ho;Jung, Hyun-Key;Lee, Hyosun;Son, Jeong-Sul
    • Journal of the Korean earth science society
    • /
    • v.34 no.6
    • /
    • pp.588-601
    • /
    • 2013
  • In geophysics and geophysical exploration fields, we can use information about inclination and azimuth in various ways. These include borehole deviation logging for inversion process, real-time data acquisition system, geophysical monitoring system, and so on. This type of information is also necessarily used in the directional drilling of shale gas fields. We thus need to develop a subminiature, low-powered, multi-functional inclination and azimuth measurement system for geophysical exploration fields. In this paper, to develop real-time measurement system, we adopt the high performance low power Micro Control Unit (made with state-of-the-art Complementary Metal Oxide Semiconductor technology) and newly released Micro Electro Mechanical Systems Attitude Heading Reference System sensors. We present test results on the development of a multifunctional real-time inclination and azimuth measurement system. The developed system has an ultra-slim body so as to be installed in 42mm sonde. Also, this system allows us to acquire data in real-time and to easily expand its application by synchronizing with a depth encoder or Differential Global Positioning System.

Georadar System Using Network-Analyzer (네트웍 분석기를 이용한 레이다탐사 시스템의 구현)

  • Cho Seong-Jun;Kim Jung-Ho;Lee Seoung Kon;Son Jeong-Sul;Chung Seung-Hwan
    • Geophysics and Geophysical Exploration
    • /
    • v.5 no.4
    • /
    • pp.272-279
    • /
    • 2002
  • During field survey of ground penetrating radar or borehole radar, we often encounter some problems which could be solved easily by modifying structure of the system such as antenna length, shape or array. In addition, it is necessary that the user could easily modify configuration of the radar system na test various array of antennas in order to verify and confirm numerical modeling results concerning radar antennas. We have developed network-analyzer-based, stepped-frequency georadar system. This system had been comprised with coaxial cable to confirm possibility of the system, then we have upgraded the system to use optical cable that is composed of optical/electric transducers, electric/optical transducers, amp, pre-amp and antennas. The software for the aquisition of data has been developed to control the system automatically using PC with GPIB communication and to display the obtained data graphically. We have tested the system in field survey na the results have been compared with those of RAMAC/GPR system.

Application and Analysis of Field Test and Geophysical Exploration for Dynamic Material Properties of Rockfill Dam (사력댐 동적물성 추정을 위한 현장조사기법 적용 및 분석)

  • Lee, Jong-Wook;Kim, Ki-Young;Jeon, Je-Sung;Cho, Sung-Eun
    • Proceedings of the Korean Geotechical Society Conference
    • /
    • 2005.10a
    • /
    • pp.352-359
    • /
    • 2005
  • In this study, seismic refraction survey and MASW at dam crest and down-hole test and cross hole test in the boring holes located in dam crest through the core are performed to fin out dynamic material properties, are needed to evaluate dynamic safety of rockfill dam using dynamic analysis method. From the field test and geophysical exploration, applied such as above, p-wave and s-wave velocity profile of each layer of dam body. Dynamic material properties, such as elastic modulus, shear modulus, poissong's ration, are obtained from p-wave and s-wave velocity profile and density profile from formation density logging test.

  • PDF

Assessment of seawater intrusion using geophysical well logging and electrical soundings in a coastal aquifer, Youngkwang-gun, Korea

  • Hwang Seho;Shin Jehyun;Park Inhwa;Lee Sangkyu
    • Geophysics and Geophysical Exploration
    • /
    • v.7 no.1
    • /
    • pp.99-104
    • /
    • 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.