• Geophysics and Geophysical Exploration
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• v.22 no.3
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• pp.116-131
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• 2019

In order to obtain high-quality high-resolution marine seismic data, the survey needs to be carried out at very low-sea condition. However, the survey is often performed with a slight wave, which degrades the quality of data. In this case, it is possible to improve the quality of seismic data by detecting the exact location of the sea bottom signal and eliminating the influence of waves or swells automatically during data processing. However, if noise is included or the sea bottom signal is weakened due to sea waves, sea bottom detection errors are likely to occur. In this study, we applied a method reducing such errors by estimating the sea bottom location, setting a narrow detection range and detecting the sea bottom location within this range. The expected location of the sea bottom was calculated using previously detected sea bottom locations for each channel of multi-channel data. The expected location calculated in each channel is also compared and verified with expected locations of other channels in a shot gather. As a result of applying this method to the noisy 8-channel high-resolution air-gun seismic data acquired off Yeosu, the errors in selecting the strong noise before sea bottom or the strong subsurface reflected signal after the sea bottom signal are remarkably reduced and it is possible to produce the high-quality seismic section with the correction of ~ 2.5 m swell effect.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.7
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• pp.811-818
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• 2014

This study was aimed to detect Submarine Groundwater Discharge (SGD) distribution image of Sea Surface Temperature (SST) using infrared band of Landsat-7 ETM+ around Jeju island. It is used to analyze SST distribution that DN value of satellite images converted into temperature. The estimation of SGD location is that extracting range of $15{\sim}17^{\circ}C$ from SST. The summer season images(July 28. 2006, Aug. 29. 2006 and Sep. 19. 2008) were used to analyze big difference between SST and temperature of SGD. The results, estimated SGD locations were occurred part of coastal area in northeastern of Jeju island.

• Economic and Environmental Geology
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• v.54 no.6
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• pp.717-731
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• 2021

We analyzed the characteristics of the habitat environment for the Seonam study area in Ulsan, the southern shore of the East Sea using bathymetry and seafloor environment data. The depth of the study area ranges from about 0 m to 23 m. In the west of the study area, the water depth is shallow with a gentle slope, and the water depth becomes deeper with a steep slope in the east. Due to the right-lateral strike-slip faults located in the continental margin of the East Sea, the fracture surfaces of the seabed rocks are mainly in the N-S direction, which is similar to the direction of the strike faults. Three seafloor types (conglomeratic-grained sandy, coasre-graiend sandy, fine-grained sandy) and rocky bottom area have been classified according to the analyses of the bathymerty, seafloor image, and surface sediment data. The rocky bottom areas are mainly distributed around Seaoam and in the northern and southern coastal area. But the intermediate zone between Seonam and coastal area has no rocky bottom. This intermediate area is expected to have active sedimentation as seawater way. The sandy sediments are widely distributed throughout the study area. Underwater images and UAV images show that Cnidarians, Brachiopods, Mollusks are mostly dominant in the shallow habitat and various Nacellidae, Mytilidae live on the intertidal zone around Seonam. Annelida and Arthropod are dominant in the sandy sediments. The distribution of marine organism in the study area might be greatly influenced by the seafloor type, the composition and particle size distribution of the seafloor sediments. The analysis of habitat environment mapping with bathymetry, seafloor data and underwater images is supposed to contribute to the study of the structure and function of marine ecosystem.