• 한국지구물리탐사학회:학술대회논문집
• /
• 2008.10a
• /
• pp.185-190
• /
• 2008

Geophysical survey were investigated in the offshore around East Sea Research Institute, Korea Ocean Research and Development Institute (Jukbyeon-myun, Uljin-gu, Gyeongsangbuk-do, Korea). The surveys were conducted aboard the R/V Jangmok in 2008 using a hull-mounted EM 3002 multi-beam echosounder. Precise bathymetry and seabed images were obtained using multi-beam and thicknesses of sedimentary layer were found through seismic survey. Submarine topography deepens parallel to the coastline to -60 m and rock mass distributed in the southeast of study area. By finding the thickness of sedimentary layer through seismic survey, a sedimentary thickness on the study area was established. Futhermore, monitoring data of bathymetry, substructure and sedimentary environment will be secured through successive geophysical investigation.

• Geophysics and Geophysical Exploration
• /
• v.16 no.4
• /
• pp.275-283
• /
• 2013

The sea dike is the most important facility of reclamation projects, and plays an important role in securing freshwater in the reservoir. Systematic research on practical approaches and data analysis techniques are lacking even though some geophysical methods such as electrical resistivity and self-potential surveys are included within the inspection processes. Hence, geophysical methods were considered for improvement of precision safety diagnosis methods after problems in the maintenance system have been identified, such as safety checks and precision safety diagnoses. In addition, geophysical methods customized according to variations in ambient environmental limiting factors such as pore pressure changes by tidal fluctuation, compaction characteristics of the fill materials, and the surface condition of the embankment were suggested.

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

• 한국지구물리탐사학회:학술대회논문집
• /
• 2011.10a
• /
• pp.149-150
• /
• 2011

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

• 한국지구물리탐사학회:학술대회논문집
• /
• 2010.10a
• /
• pp.103-106
• /
• 2010

• Geophysics and Geophysical Exploration
• /
• v.7 no.2
• /
• pp.121-129
• /
• 2004

The geostatistical approach was applied to integrate MT (Magneto-telluric) resistivity data and borehole information for the spatial RMR (Rock Mass Rating) evaluation. Generally, resistivity of the subsurface is believed to be positively related to the RMR, thus the resistivity and borehole RMR information was combined in a geostatistical approach. To relate the two different sets of data, we take the MT resistivity data as secondary information and estimate the RMR mean values at unsampled points by identification of the resistivity to the borehole data. Two types of approach are performed for the estimation of RMR mean values. Then the residuals of the RMR values around the borehole sites are geostatistically modeled to infer the spatial structure of difference between real RMR values and estimated mean values. Finally, this geostatistical estimation is added to the previous means. The result applied to a real situation shows prominent improvements to reflect the subsurface structure and spatial resolution of RMR information.

• Journal of the Korean Geophysical Society
• /
• v.4 no.1
• /
• pp.11-20
• /
• 2001

Seismic refraction and electrical resistivity surveys were conducted in Bangeosan Maaebul site located in Haman, Kyungnam, in order to present geophysical safety analysis method for masonry cultural properties. Seismic refraction exploration revealed that the ground was composed of three layers in term of seismic wave velocity; the upper, medium, and lower layers. The low velocity ranging from 308 to 366 m/sec in upper layer suggests weathered soil, the intermediate velocity from 1906 to 2090 m/sec in the medium layer indicates weathered rocks, and the high velocity from 5061 to 5650 m/sec in the lower layer implies extremely hard rocks. Our seismic result suggests that the upper and medium layer around the Maaebul should be reinforced to support the construct. The result of electric resistivity survey shows that there exists a low resistivity zone, ranging from 131 to 226 Ohm-m, at the right side of the Maaebul with the direction of NE-NNE. This area is the weakness zone as it plays role of the underground water passage in rainy season.

• Geophysics and Geophysical Exploration
• /
• v.26 no.4
• /
• pp.238-267
• /
• 2023

Studies on Earth's rotation and tide since the 19th century are briefly summarized. The theories of precession, nutation, polar motion, and periodic/secular changes in the rate of rotation are described individually. In addition, a brief review of the Milankovitch theory - the hypothesis of the relationship between the Earth's spin/orbital rotational state and the ice ages - is given. Finally, Earth's tides and their theoretical models are briefly explained. Some detailed technical content is summarized in the appendices.

• 한국지구물리탐사학회:학술대회논문집
• /
• 2004.06a
• /
• pp.308-311
• /
• 2004