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Kim, Han Joon; Han, Seunghee; Lee, Gwang Hoon; Huh, Seong

doi:10.1023/a:1004573816915

Cited by 55 publications

(8 citation statements)

References 39 publications

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“…A stated by Ryu et al (2009), the reference velocity-depth function was found to be quite constant for large regions of the deep Ulleung Basin, which is also reflected in the nature of the uppermost seismic facies defined (see discussion below). The regional velocity-depth relation defined by Ryu et al (2009) are in general agreement with those from OBS refraction seismic experiments in the region according to Kim et al (1998) and well-log data acquired during UBGH1 and UBGH2. Significant deviations from this reference velocity-depth profile may be interpreted as due to high velocity gas hydrate or low velocity free gas, although velocity variations due to lateral changes in sediment type [e.g., in regions of wide-spread mass-transport deposits, where sediment consolidation cannot be excluded (see discussion in .…”

Section: Seismic Velocity Structure and Bsrssupporting

confidence: 78%

Gas hydrates in the Ulleung Basin, East Sea of Korea

Ryu¹,

Riedel²

2017

Terr. Atmos. Ocean. Sci.

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To develop gas hydrates as a potential energy source, geophysical surveys and geological studies of gas hydrates in the Ulleung Basin, East Sea off the east coast of Korea have been carried out since 1997. Bottom-simulating reflector (BSR), initially used indicator for the potential presence of gas hydrates was first identified on seismic data acquired in 1998. Based on the early results of preliminary R&D project, 12367 km of 2D multichannel reflection seismic lines, 38 piston cores, and multi-beam echo-sounder data were collected from 2000 to 2004. The cores showed high amounts of total organic carbon and high residual hydrocarbon gas levels. Gas composition and isotope ratios define it as of primarily biogenic origin. In addition to the BSRs that are widespread across the basin, numerous chimney structures were found in seismic data. These features indicate a high potential of the Ulleung Basin to host significant amounts of gas hydrate. Dedicated geophysical surveys, geological and experimental studies were carried out culminating in two deep drilling expeditions, completed in 2007 and 2010. Sediment coring (including pressure coring), and a comprehensive well log program complements the regional studies and were used for a resource assessment. Two targets for a future test-production are currently proposed: pore-filling gas hydrate in sand-dominated sediments and massive occurrences of gas hydrate within chimney-like structures. An environmental impact study has been launched to evaluate any potential risks to production.

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Section: Seismic Velocity Structure and Bsrssupporting

confidence: 78%

Gas hydrates in the Ulleung Basin, East Sea of Korea

Ryu¹,

Riedel²

2017

Terr. Atmos. Ocean. Sci.

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“…Both the western edge of the Japan Basin and the Tsushima Basin are characterized by strong attenuation anomalies (Figures 4 and 2b) and thicker oceanic crustal structures (H. Kim et al., 1998; Sato et al., 2014). The hot mantle flows seem to provide a large amount of molten material to form a thick igneous crust in the Tsushima Basin and on the northwestern edge of the Japan Basin during the opening of the Japan Sea.…”

Section: Discussionmentioning

confidence: 99%

“…The hierarchical structure includes a sedimentary layer and two oceanic layers with their P-wave velocities of 3.3-6.2 and 6.6-6.8 km/s, respectively (Figure 4) (Hirata et al, 1992). The crust in the Yamato Basin, the Tsushima Basin and the western edge of the Japan Basin is significantly thicker than that in the eastern Japan Basin, although features similar layering structures (H. Kim et al, 1998;Sato et al, 2004Sato et al, , 2014. The thicker oceanic crust and poor magnetic lineation in the Tsushima and Yamato Basins may be caused by thermal perturbations under the lower crust during the shorter opening period (Hirata et al, 1989;Isezaki & Uyeda, 1973;H.…”

Section: Heat-driven Reworking Of the Back-arc Crustmentioning

confidence: 96%

“…The broadband waveform data used in this study were collected from the China Earthquake Networks Center (CENC), the Data Management Center of the China National Seismic Network at the Institute of Geophysics, China Earthquake Administration (SEISDMC, https://doi.org/10.7914/SN/CB2010), the Incorporated Research Institutions for Seismology Data Management Center (IRIS-DMC) at https://ds.iris.edu/wilber3/find_event (last (Hirata et al, 1992;H. Kim et al, 1998;Sato et al, 2004Sato et al, , 2014, with their layered structures shown on the right.…”

Section: Data Availability Statementmentioning

confidence: 99%

“…The red-shaded areas indicate strongly attenuated regions. The black-dashed lines marked with serial numbers represent previous seismic survey lines(Hirata et al, 1992;H. Kim et al, 1998;Sato et al, 2004Sato et al, , 2014, with their layered structures shown on the right.…”

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confidence: 99%

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“Double Door” Opening of the Japan Sea Inferred by Pn Attenuation Tomography

Yang

Zhao

Xie

et al. 2022

Geophysical Research Letters

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The eastern Asian and western Pacific margins, including the Japan Sea, are areas related to plate subduction and extrusion due to the collision of the Pacific, Philippine Sea, Eurasian, and Okhotsk plates during the late Mesozoic and Cenozoic (Lallemand & Jolivet, 1985;Martin, 2011) (Figure 1a). However, the opening mechanism of the Japan Sea, a representative example of a virtually intact continent-ocean back-arc system, is still unclear and under debate (Van Horne et al., 2017). In general, the formation of a marginal sea in combination with back-arc extension can be ascribed to two driving mechanisms: small-scale convection in mantle wedge induced by descending lithosphere (Toksöz & Bird, 1977) (Figure 1b) and ascending convection generated by both the foundering of the descending lithosphere and seaward migration of the trench (Uyeda & Kanamori, 1979) (Figure 1c). However, the Japan Sea may have experienced complex evolution driven by the superposition of multiple mechanisms, which finally produced a diamond-shaped ocean (Van Horne et al., 2017).The Japanese Islands were part of the northeastern edge of the Asian continent before the Late Cretaceous (Lallemand & Jolivet, 1985). Through short-term continental breakage and seafloor spreading, the Japan Sea began to open and gradually met the Pacific and Philippine plates at a trench-trench-trench triple junction. Kawai et al. (1961) discovered the difference in the magnetization directions of the rocks collected in the southwestern and northeastern parts of the Japan Arc and suggested that this contrast may have been caused by deformation of the Japanese Islands in the late Mesozoic or early Tertiary. Otofuji et al. (1985) further proposed a

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Seismic constraints of the formation process on the back‐arc basin in the southeastern Japan Sea

Sato

Kodaira

et al. 2014

JGR Solid Earth

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To clarify the formation process of the back-arc basin in the Japan Sea, which is located next to the northwestern Pacific, a seismic survey using ocean bottom seismographs and an air gun array was undertaken in areas from the northern Yamato Basin to the coast of the northeastern Japan Island Arc off Awa-shima Island. The crust beneath the northern Yamato Basin off Awa-shima Island is approximately 16 km thick. The upper and lower crusts are, respectively, about 5 km thick with a steep velocity gradient and about 10 km thick with a gentle velocity gradient. In the basin, there are very few units with P wave velocity of 5.4-6.0 km/s, corresponding to the continental upper crust. The crustal structure of the northern Yamato Basin has characteristics of thicker oceanic crust. The high-velocity lowermost crust in the northern Yamato Basin with 7.2-7.4 km/s might show melt formed by a slightly high mantle temperature during the opening of the basin. However, the crust beneath the areas from the Sado Ridge to the coast, which is approximately 25-26 km thick, is slightly thinner than that of the continental crust and island arc crust. The crustal structure beneath this area is inferred to be a rifted continental and/or a rifted island arc crust.

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Untitled

Cited by 55 publications

References 39 publications

Gas hydrates in the Ulleung Basin, East Sea of Korea

Gas hydrates in the Ulleung Basin, East Sea of Korea

“Double Door” Opening of the Japan Sea Inferred by Pn Attenuation Tomography

Seismic constraints of the formation process on the back‐arc basin in the southeastern Japan Sea

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