• Geophysics and Geophysical Exploration
• /
• v.18 no.3
• /
• pp.115-124
• /
• 2015

A modified electrical resistivity survey has been suggested and applied to a leakage detection problem of concrete barrage. We suggest the modified electrical resistivity methods using electrodes floating on the water and apply line current sources instead of conventional point current sources in order to facilitate simple analysis. In addition, the study introduced the following three variations of modified electrode array: Direct potential array, Parallel potential array and Cross potential array. These arrays were tested and investigated through numerical experiment, physical model experiment and geophysical field exploration in order to verify their applicability to the water leakage detection of a concrete barrage. When water leakage occurred, all kind of array operations demonstrated distinct changes of aspects of potential difference in graphs obtained by not only the numerical and physical model experiments but also geophysical field exploration. Therefore, this modified electrode arrays of electrical resistivity survey, which has been adapted to the concrete barrage, has been found to be a useful method to detect water leakage.

• The Journal of Engineering Geology
• /
• v.20 no.1
• /
• pp.71-78
• /
• 2010

The Gagok mine is a contact metasomatic deposit, located at Gagok-myeon, Samcheok city and Cheoram-dong, Taebaek city, Gangwon province. The deposit lies within the limestone of Myobong and Pungchon formations, and exists the contact of intrusive granite porphyry. In order to determine the direction and extension of mineralization in the gallery and around the entrance of the ore deposit, we used the ground magnetic survey, the direct current (dc) resistivity survey using dipole-dipole array, and resistivity tomography survey. The ground magnetic survey did not detect the anomalous zone due to ore deposit, while the dc resistivity survey and resistivity tomography survey were successful in delineating the anomalous zone related to the extension of fault toward $N50^{\circ}W$.

• Journal of the Korean earth science society
• /
• v.40 no.2
• /
• pp.177-187
• /
• 2019

Several volcanic activities have continued in Mt. Baekdu since the Millennium eruption, and these phenomena have increased the need for volcanic activity surveillance. Various geophysical approaches are needed to obtain the depth and size of magma chamber that lie several kilometers below the surface. We examined the applicability of direct-current resistivity survey in this study. In order to explore the deep magma chamber of Mt. Baekdu, which has a spatial limitation due to the borderline, a large-scale survey with a length of tens of kilometers should be conducted. This type of survey requires a distributed measurement system and optimized exploration designs. Therefore, we propose survey designs taking advantage of our developed distributed acquisition system and analyze the applicability using numerical simulation. We confirmed that our designs that use single survey line with offline transmitting points show comparable results to the conventional 3D survey. It is expected that our research result can contribute to the deep geophysical exploration in Mt. Baekdu.

• Economic and Environmental Geology
• /
• v.34 no.5
• /
• pp.499-506
• /
• 2001

The geophysical monitoring technique using the high resolution time-domain electromagnetic (TEM) method with a coincident loop away was applied for determination of an underground seawater flow in the coastal areas. In comparison of the TEM monitoring to direct current (DC) resistivity monitoring, the TEM response to the under ground seawater flow is less sensitive than the DC resistivity response. However, the TEM monitoring is more effective in terms of measuring time, survey expense, and real-time data processing than the DC monitoring thor evaluating the spatial distribution of the fresh water-seawater transition zone in a regional area.