The 3.5 kHz scismic survey was carried out for studying the distribution pattern of the unconsolidated sedements of the Yeosu Sound on the southern coast of the Korean Peninsula. Field data originally recorded in analog are converted and processed digitally to recover the high-resolution acoustic profiles. Across the north-south trending channel with the depth of 20∼30m, different seismic facies types are observed in the top section of sediments. The western part is characterized by the continuous high-amplitude subparallel reflectores within which the acoustic turbidity as a token of ghe presence of gas is commonly observed, whereas the counterpart largely shows poor reflectors and has shallow acoustic basement toward the north. The dissimilariry of the seismic expression across the channel can be interpreted as the result of the change of depositional environment caused by relative sea-level fluentuations of the late-Quatemary. During the last glacial periods, the Yeosu Sound was exposed and croded by the paleo-Seomjin Reiver. By the following rapid rise of sea level, it was covered by the transgressive sand sheet. When the sea level reached near the present position, the muddy sediment has accumulated only in the western part of the Yeosu Sound as its depositional front has moved toward the north. It is partly caused by the asymmetrical tidal current in the Yeosu Sound where the flood near the bottom has stronger current flow and contains more suspended sediments.
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