https://repository.kopri.re.kr/handle/201206/5320 Sat, 04 Apr 2026 06:30:45 GMT 2026-04-04T06:30:45Z https://repository.kopri.re.kr/handle/201206/7238 Title: The stability of gas hydrate field in the northeastern continental slope of Sakhalin Island, Sea of Okhotsk, as inferred from analysis of heat flow data and its implications for slope failures Authors: Kim, Young-Gyun; Hitoshi Shoji; Alexander Salomatin; Anatoly Obzhirov; Boris Baranov; Jin, Young Keun; Lee, Sang-Mook Abstract: The sudden release of methane from seas due to ocean warming and/or sea level drop, leading to extensive mass wasting at continental margins, has been suggested as a possible cause of global climate change. In the northeastern continental slope of the Sakhalin Island (Sea of Okhotsk), numerous gas hydrate-related manifestations have been reported, including hydroacoustic anomaly (gas flare) in the water column, pockmarks and mounds on the seafloor, seepage structures and bottom-simulating reflectors (BSRs). The gas hydrate found at 385 mbsl represents the shallowest occurrence ever recorded in the Okhotsk Sea. In this study, we modeled the gas hydrate stability zone (GHSZ) using methane gas composition, water temperature and geothermal gradient to see if it is consistent with the observed depth of the BSR. An important distinction can be made between the seafloor containing seepage features and normal seafloor in terms of their thermal structure. The depth of the BSR matches well with the base of GHSZ estimated from the background heat flow (geothermal gradient). A large slope failure feature is found in the northern Sakhalin continental slope. We explore the possibility that this failure was caused by gas hydrate dissociation, based on the past climate change history and inference from the GHSZ calculation. Prediction of the natural landslide is difficult however, new stratigraphic evidence from subbottom profiles suggests that the landslide occurred at 20 ka which is roughly consistent with the late stage of the Last Glacial Maximum. Tue, 01 Jan 2013 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/7238 2013-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/7237 Title: Landslides on the Eastern Slope of Sakhalin Island as Possible Tsunami Sources Authors: B. V. Baranov; K. A. Dozorova; Jin, Young Keun; A. B. Rabinovich; E. A. Kulikov; L. I. Lobkovskii Abstract: An underwater landslide located in the central part of the eastern slope of Sakhalin Island was found and mapped during investigations under the auspices of the Korean？ Russian Project Sakhalin Slope Gas Hydrates (SSGH). The peculiarities of the study region structure together with the expected seismic intensity of grade 8 give grounds to suppose the probability of further destruction of the depression slopes and formation of landslides of different volumes. In this case, the tsunami can be a hazard for the central part of the eastern coast of Sakhalin, where the infrastructure is currently intensively developed in relation to the prospecting of oil and gas resources within the Sakhalin？ 2 Project. Tue, 01 Jan 2013 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/7237 2013-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/8410 Title: KOPRI research activities on gas hydrates in the cold seas: Antarctic, Okhotsk and Arctic Sea Authors: Jin, Young Keun; Hong, Jong Kuk; Nam, SangHeon; Kim, Yeadong; Kang, Sung-Ho; Chung, Kyung Ho Abstract: Because gas hydrates are formed in low temperature and high pressure environments, cold seas including Polar and Okhotsk Seas are very favorable areas for gas hydrate formation on earth. KOPRI collected single-/multi-channel seismic reflection data on the South Shetland continental margin, Antarctic Peninsula since 1993 using RV Onnuri and Yuzhmogeologya. Seismic data show that Bottom Simulating Reflectors (BSRs) are widely distributed on the South Shetland margin. We estimated the total volume of gas hydrate in the area. Assuming that gas hydrates exist only where BSRs are observed, the total volume of gas hydrates along the seismic profiles in the area is about 4.8 × 1010 m3 (7.7 ×1012 m3 volume of methane at standard temperature and pressure). Multidisciplinary surveys have been conducted to investigate gas seepage and gas hydrate accumulation on the Sakhalin continental slope (SS), Sea of Okhotsk, during joint Korea-Russia-Japan expeditions conducted from 2003 to 2011 (CHAOS and SSGH projects). Active gas seeps in a gas hydrate province on the SS were evident from features in the water column, on the seafloor, and in the subsurface: well-defined hydroacoustic anomalies (gas flares), side-scan sonar structures with high backscatter intensity (seepage structures), bathymetric structures (pockmarks and mounds), gas- and gas-hydrate-related seismic features (bottom-simulating reflectors, gas chimneys, high-amplitude reflectors, and acoustic blanking), high methane concentrations in seawater, and gas hydrates in sediment near the seafloor. These expressions were generally spatially related; a gas flare would be associated with a seepage structure (mound), below which a gas chimney was present. As the ice-breaker RV Araon in 2009 was launched, KOPRI will expand gas hydrate research activities in the polar sea. KOPRI has developed a Korea-Canada-US international research project to focus on geological, geophysical and oceanographic investigations of the Beaufor Sun, 01 Jan 2012 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/8410 2012-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/8409 Title: Occurrence, distribution and expression of gas seeps and gas hydrates on the northeastern continental slope of Sakhalin Island, Sea of Okhotsk Authors: Jin, Young Keun; B. Baranov; A. Obzhirov; H. Shoji Abstract: Multidisciplinary surveys were conducted to investigate gas seepage and gas hydrate accumulation on the northeastern Sakhalin continental slope (NESS), Sea of Okhotsk, during joint Korea-Russia-Japan expeditions conducted from 2003 to 2007 (CHAOS and SSGH projects). One hundred sixty one gas seeps were detected in a 2000 km2 area of the NESS (between 53°45′N and 54°45′N). Active gas seeps in a gas hydrate province on the NESS were evident from features in the water column, on the seafloor, and in the subsurface: well-defined hydroacoustic anomalies (gas flares), side-scan sonar structures with high backscatter intensity (seepage structures), bathymetric structures (pockmarks and mounds), gas- and gas-hydrate-related seismic features (bottom-simulating reflectors, gas chimneys, high-amplitude reflectors, and acoustic blanking), high methane concentrations in seawater, and gas hydrates in sediment near the seafloor. These expressions were generally spatially related; a gas flare would be associated with a seepage structure (mound), below which a gas chimney was present. The spatial distribution of gas seeps on the NESS is controlled by four types of geological structures: faults, the shelf break, seafloor canyons, and submarine slides. Gas chimneys that produced enhanced reflection on high-resolution seismic profiles are interpreted as active pathways for upward gas migration to the seaf007 (CHAOS and SSGH projects). One hundred sixty one gas seeps were detected in a 2000 km2 area of the NESS (between 53°45′N and 54°45′N). Active gas seeps in a gas hydrate province on the NESS were evident from features in the water column, on the seafloor, and in the subsurface: well-defined hydroacoustic anomalies (gas flares), side-scan sonar structures with high backscatter intensity (seepage structures), bathymetric structures (pockmarks and mounds), gas- and gas-hydrate-related seismic features (bottom-simulating reflectors, gas ch Sun, 01 Jan 2012 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/8409 2012-01-01T00:00:00Z