Physical and acoustic properties of shelf sediments, the South Sea of Korea

Laboratory determinations of compressional wave velocity, porosity, density and sediment texture have been conducted on samples collected from the inn er shelf Holocene mud sediment in the South Sea and southern part of the Ea st Sea of Korea. Thirty-five piston core samples were used for the measurem ent. Mean grain size decreases seaward reflecting the distance from source. Velocity decreases with increasing water depth. Porosity and clay content increase gradually with deepening bathymetry on the inner shelf. The study area can be divided into three different areas (Namhae, Pusan and Ulsan) by sediment source, texture and physical properties. Velocity increases from west to east (Namhae --> Pusan --> Ulsan). Porosity has a pattern that is i nverse to that of velocity. Sediment texture (mean grain size and clay cont ent) is a very important factor to determine physical and acoustic properti es of sediment. The geoacoustic properties of the three study areas general ly coincide well with that of Hamilton's (1970) North Pacific continental t errace sediment. Ulsan area is a little different from the Hamilton's model , which has a relatively higher velocity at the same textural range. The di fference is believed to be related to the lowest clay content in Ulsan area . (C) 2001 Elsevier Science B.V. All rights reserved.