• Geophysics and Geophysical Exploration
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• v.7 no.4
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• pp.256-261
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• 2004

This study grafts geophysics on modem archaeology and approaches with scientific and systematic methods to an excavation plan or archaeological study by means of GPR exploration which can assist archaeologists to study Wolseong fortress without excavating it. We investigated the areas in front of Seokbinggo (ice storage facility built of stone) and in the eastern corner of the castle with GPR. As a result, we detected 7 large squared building foundations, stone walls, an entrance for the fortress, many other foundation stones, a road and a garden.

• 한국지구물리탐사학회:학술대회논문집
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• 2003.11a
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• pp.335-339
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• 2003

The estimation of seawater intrusion into deep aquifers has been becoming an important subject in terms of site characterization for geological disposal of radioactive waste. Conventional direct-current resistivity methods have been used for ground water explorations and recently have been applied to environmental problems. However, electromagnetic methods are more practical and useful for such a deep investigation. We consider audio-frequency magnetotelluric (AMT) and surface-to-borehole electromagnetic (EM) tomography methods as promising tools for the investigation of deep aquifer. These methods were tested in the Hasunuma area, Chiba Prefecture, Japan. Although the study area is in an urban area, high-quality AMT data were acquired, which was mainly accomplished by night-time data recording and remote-reference data processing. One-dimensional inversion results of the AMT data revealed two extremely conductive zones, which is consistent with the electrical conductivity profile of pore water in core samples. It can be interpreted as the seawater intrusions into both zones. However, the chemical analysis of the groundwater sampled in the deep zone suggests that this groundwater must be fossil seawater that had been confined during sedimentation processes. In addition, the permeability coefficient of the deep layer is very low. Thus the deep conductive zone corresponds to the fossil seawater regarded as being difficult to flow.

• Geophysics and Geophysical Exploration
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• v.23 no.3
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• pp.178-191
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• 2020

Unmanned aerial vehicle (UAV) technologies have grown rapidly over the past decade. Simultaneously, there is an increasing need for efficient high-resolution exploration techniques in complex environments. As a result, exploration technology using UAVs is gaining attention as an efficient method to complement and replace existing exploration technologies. In particular, magnetic exploration technology with UAVs is rapidly gaining ground in the field of exploration and is expected to be actively used in this field in the future. To properly use such technology in domestic exploration, it is necessary to review the latest research trends. Accordingly, this paper introduces the current state of UAV-based magnetic exploration technology studies and, based on this, discusses future research directions.

• Geophysics and Geophysical Exploration
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• v.14 no.2
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• pp.152-157
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• 2011

The small-loop electromagnetic (EM) method is one of the rapid and non-destructive geophysical methods and has been used widely for many geophysical investigations, particularly for shallow engineering and environmental surveys. Especially in the shallow marine environment, the small-loop EM technique is very effective because of rapid and convenient data acquisition, large signal and low noise level. However, the method has been rarely applied in the very conductive marine environment since it's penetration or investigation depth might be considered too low. In this study, we demonstrated that the small-loop EM method can be effectively applied in the extremely conductive marine environment through the analysis of 1D small-loop EM data. Furthermore, we confirmed that the resistivity distribution under the sea bottom can be quantitatively predicted from the 1D inversion results of synthetic and field data.

• Geophysics and Geophysical Exploration
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• v.13 no.4
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• pp.397-406
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• 2010

Resistivity method is a practical and effective geophysical technique to detect leakage zones in embankment dams. Generally, resistivity survey conducted along the crest assumes that the embankment dam has a 2D structure. However, the 3D topography of the embankment distorts significantly resistivity data measured on anywhere of the dam. This study evaluates the influence from 3D effects created by specific dam geometry and effects of water level fluctuations through the 3D finite element modeling technique. Also, a comparison between different locations of survey line are carried out, and topographic correction technique is developed for the resistivity data obtained along the embankment dam. Furthermore, using synthetic resistivity data for an embankment dam model with leakage zone, detectability of leakage zones is estimated through 2.5D inversion.

• Geophysics and Geophysical Exploration
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• v.21 no.4
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• pp.244-254
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• 2018

The first geophysical technique applied to the agricultural sector in Korea was electrical resistivity sounding and conducted in purpose of groundwater exploitation in the 1970s. According to the diversity of agricultural activities since the 1990s, various geophysical methods including electrical resistivity, electromagnetic induction, and self-potential method were applied to several agricultural fields such as soil characterization with saline concentration in vast reclaimed area, delineation of seawater intrusion regions in costal aquifer, safety inspection of embankment dikes with leakage problem, detection of ground subsidence from overpumping and tracing of groundwater aquifer contamination by leachate from livestock mortality burial or waste burial site. This paper introduces representative geophysical techniques that have been utilized in various agricultural fields and suggests several ways to develop the geophysical methods required for the precision agriculture field in the near future based on the past achievements.

• Geophysics and Geophysical Exploration
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• v.14 no.2
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• pp.176-178
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• 2011

• Geophysics and Geophysical Exploration
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• v.15 no.4
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• pp.249-251
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• 2012

• Geophysics and Geophysical Exploration
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• v.12 no.4
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• pp.367-369
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• 2009

• Geophysics and Geophysical Exploration
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• v.17 no.4
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• pp.253-259
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• 2014