Depositional and geoacoustic characteristics of the northern East China Sea
Ryang, Woo Hun
Chonbuk National University ([email protected])
Abstract
In the northern East China Sea, a total of 280 line kilometers of high-resolution subbottom and air-gun seismic profiles with 16 piston cores is used for analysis of depositional and geoacoustic characteristics. The successions are divisible into 3 seismic units within a depth of 100 m below seafloor, based on acoustic characteristics of the 3.5 kHz SBP, first-trace seismic, and stack 64-channel profiles. The seismic units could name tentatively as the uppermost one of Unit 1, second of Unit 2, and third of Unit 3. In the same location, three kinds of seismic data were acquired and processed to three seismic sections with different seismic characters according to a target depth, respectively. Geoacoustic data consist of P-wave speed and attenuation, sound speed ratio, and S-wave speed.
In the study area, the uppermost one, Unit1, is characterized by chaotic or hummocky reflections without internal reflectors. The unit is less than 10 m thick showing a sheet-like external form with varying lateral extent. Unit 2 shows semi-transparent reflections alternating with faintly stratified or discontinuous reflectors. The uppermost part of Unit 2 is shown in the SBP and the whole unit is shown in the first-trace and stack profiles. Unit 3 is characterized by continuous transparent acoustic reflectors, partly truncated. These three units are deposited In the northern East China Sea during the late Quaternary.
Keywords : East China Sea, geoacoustic, Quaternary
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