Bottom-simulating reflectors in the Korea Plateau, East Sea (Japan Sea)

Title
Bottom-simulating reflectors in the Korea Plateau, East Sea (Japan Sea)
Author(s)
김한준; 이광훈
KIOST Author(s)
Kim, Han Joon(김한준)
Publication Year
2006-07-20
Abstract
Multi-channel seismic reflection profiles from the trough areas of the southern South Korea Plateau, East Sea (Sea of Japan) (Fig. 1A), reveal bottom-simulating reflectors (BSRs). BSRs, recognized from various continental margin and deep-water settings, mark: (1) the base of gas hydrate-bearing sedi-ments or (2) the opal-A/opal-CT phase boundary. The gas-hydrate BSR results from a sharp acoustic impedance contrast between the high-velocity gas-hydrate stability zone above and low-velocity free gas below [Bryan, 1974]. The gas-hydrate BSR thus displays high seismic amplitude and a reverse po-larity with respect to the seafloor reflection. There are about 80 localities worldwide where the gas hy-drate has been inferred from various data; gas-hydrate samples have been recovered at over 20 of the-ses locations [Kvenvolden and Lorenson, 2002]. In contrast, the opal-A/opal-CT BSR has been recog-nized in a limited number of cases [e.g., Davies and Cartwright, 2002]. This BSR results from diagene-sis of biogenic silica from opal-A to opal-CT during burial [Murata and Nakata, 1974]. Therefore, a den-sity increase occurs across the interface between the two forms of opal, producing an acoustic imped-ance contrast adequate to cause a strong reflection with a positive polarity. In this study, we inferred the origin of the BSR observed in the multi-channel seismic reflection data from the southern South Korea Plateau in the East Sea (Japan Sea). We analyzed instantaneous fre-quency, reflectivity, and acoustic impedance to explore the validity of our interpretation. We also esti-mated the geothermal gradients from the sub-bottom depth of the BSR.
URI
https://sciwatch.kiost.ac.kr/handle/2020.kiost/30939
Bibliographic Citation
Korea Conference on Innovative Science and Technology (KCIST-2006), pp.285 - 288, 2006
Publisher
한국과학재단
Type
Conference
Language
English
Publisher
한국과학재단
Related Researcher
Research Interests

Marine Geophysics,Marine Active Fault Study,Exploration Seismology,해양지구물리,해저단층연구,탄성파탐사

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