Geoacoustic model based on physical property characterization of the southeastern shelf sediments (Korea Strait) of Korea

Abstract

Deep-core samples collected from the southeastern shelf (Korea Strait) of Korea were used to characterize physical properties of the area with respect to burial depth. Laboratory analyses of the acoustic and physical properties of the samples were conducted and shear-wave velocity, velocity ratio, and Poisson’s ratio were calculated. Geoacoustic and physical property data at the two sites were in correlation with the lithological units alternating between sandy mud and muddy sand at sedimentary depth. Geoacoustic units (GAUs) identified from sites 19ESDP-104 and 21ESDP-203 were divided into 6 and 15 units with sedimentary depth, respectively, and geoacoustic models were developed for the sedimentary layers around these sites. This suggests that the physical properties are not only controlled by lithology and compaction caused by dewatering with burial depth but also by different sedimentary environments after deposition. Based on the velocity ratio and velocity anisotropy (particularly at site 21ESDP-203), clay particles within the sediment layers had a greater effect on compaction owing to the overburden pressure with burial depth.