Chirp (2–7 kHz) echo characters and geotechnical properties of surface sediments in the Ulleung Basin, the East Sea

Abstract

High-resolution (chirp, 2–7 kHz) reflection profiles from the southern continental slope and basin plain of the Ulleung Basin reveal three echo types. Sediment texture and geotechnical properties were analyzed using 22 piston cores. Echo type 1 shows a sharp bottom echo with discrete, continuous subbottom reflectors with a flat or undulatory upper surface interpreted as turbidite/hemipelagic sediment. It is dominant in the basin plain. Echo type 2 is characterized by laterally wedged, an acoustically transparent masses (debrites). This type occurs in the southern lower slope and base-of-slope area. Echo type 3 shows irregular blocky/lumpy or hyperbolic masses with various amount of internal deformation, (interpreted as slide/slump deposits). It occurs in the middle to upper slope area. These echo types show a zonal distribution.