Sub-bottom profiles at massive gas hydrate recovery area between the Umitaka Spur and the Ogi Spur in the Sea of Japan

Massive gas hydrates of biogenic methane were recovered from mound structures at ~20 km northeast to the Umitaka Spur in the Sea of Japan. Mound structures at the Umitaka Spur are associated with thermogenic methane. This is owing to influence of hydrocarbon source rocks at deep sediment depths. These source rocks are widely distributed for the oil and gas fields along the eastern margin of the Sea of Japan. Therefore, the local occurrence of intensive biogenic methane production suggests unique trigger in deep. Investigation of this area and comparison with the Umitaka spur will be useful for understanding complicated nature in deep sediment depths.
Sub-bottom profiles (SBPs) were obtained during the 7K18 cruise (September 2018) and the 2K19 cruise (July 2019) by R/V Kaiyo Maru No.7 and R/V Kaiyo Maru No.2 of the Kaiyo Engineering Co., Ltd. (http://kaiyoeng.com/eng/), respectively. A sub bottom profiler (2000DSS of EdgeTech) was towed during the 7K18 cruise and four SBPs (SBP_Site4-A, _Site4-B, _Site5-D, and _Site5-E, respectively) crossing the mound structures were obtained. Position of the towed profiler was obtained by an ultra-short baseline (USBL) acoustic positioning system (cNODE MiniS 34-180 of Kongsberg Maritime) attached to the profiler. SBPs during the 2K19 cruise were obtained using an equipment attached to the ship bottom (TOPAS PS18 of Kongsberg). Two SBPs (SBP_B and _G, respectively) were obtained.

Uploaded data
Topography map with locations of 6 SBPs

SBP (7K18); four SBPs obtained during the 7K18 cruise

SBP (2K19); two SBPs obtained during the 2K19 cruise

SEG-Y (7K18); four SEG-Y files from the 7K18 cruise

SEG-Y (2K19) and SEG-Y (2K19)_2; two SEG-Y files from the 2K19 cruise
(note that file format “.seg” in SEG-Y (2K19) was changed to “.sgy” in SEG-Y (2K19)_2)

Profiler track (7K18); track of towed sub bottom profiler during the 7K18 cruise
Column “J” and “K” of “Original data” are used for “for Generic Mapping Tools”.

Profiler track (2K19); track of sub bottom profiler (same with ship track) during the 2K19 cruise
Column “I” and “J” of “Original data” are used for “for Generic Mapping Tools”.

在日本海距御牧海脊（Umitaka Spur）东北约20公里的丘状构造中，采获了大量生物成因甲烷天然气水合物。御牧海脊的丘状构造与热成因甲烷相关，这归因于深部沉积层中烃源岩的影响。这类烃源岩广泛分布于日本海东部边缘的油气田区域。因此，局部出现的高强度生物成因甲烷生成作用，暗示了深部存在独特的触发机制。对该区域开展调查并与御牧海脊进行对比，将有助于理解深部沉积层的复杂地质特征。

本数据集的浅地层剖面（Sub-bottom Profiles, SBPs）分别由海洋工程有限公司（Kaiyo Engineering Co., Ltd.）旗下的"海洋丸7号"（R/V Kaiyo Maru No.7）与"海洋丸2号"（R/V Kaiyo Maru No.2）科考船，于2018年9月的7K18航次、2019年7月的2K19航次中采集获取。7K18航次采用拖曳式浅地层剖面仪（EdgeTech 2000DSS）开展作业，共获得4条横穿丘状构造的浅地层剖面，编号依次为SBP_Site4-A、_Site4-B、_Site5-D及_Site5-E。拖曳式剖面仪的位置由安装于设备本体的超短基线（Ultra-short Baseline, USBL）声学定位系统（Kongsberg Maritime cNODE MiniS 34-180）测定。2K19航次则采用安装于船底的浅地层剖面设备（Kongsberg TOPAS PS18）进行作业，共获得2条浅地层剖面，编号依次为SBP_B及_G。

上传数据
1. 标注6条浅地层剖面位置的地形地貌图
2. SBP (7K18)：7K18航次采集的4条浅地层剖面数据
3. SBP (2K19)：2K19航次采集的2条浅地层剖面数据
4. SEG-Y (7K18)：7K18航次采集的4份SEG-Y格式数据文件
5. SEG-Y (2K19)与SEG-Y (2K19)_2：2K19航次采集的2份SEG-Y格式数据文件（注：原SEG-Y (2K19)的文件后缀为".seg"，SEG-Y (2K19)_2已将后缀修改为".sgy"）
6. 剖面仪航迹(7K18)：7K18航次拖曳式浅地层剖面仪的航行轨迹数据，"原始数据"的J、K列可用于通用制图工具（Generic Mapping Tools, GMT）
7. 剖面仪航迹(2K19)：2K19航次浅地层剖面仪的航行轨迹数据（与船舶航迹一致），"原始数据"的I、J列可用于通用制图工具