In the Kumano forearc basin, offshore SW Japan, the potential occurrence of hydrocarbons has been inferred from both geophysical surveys which point to the presence of natural gas hydrates, and geochemical analyses of gas samples recovered from boreholes and submarine mud volcanoes. The forearc basin is located in the inner part of the Nankai Trough where the Philippine Sea plate is subducting northwards beneath SW Japan. The basin succession unconformably overlies a deformed accretionary prism complex. Hydrocarbons with both microbial and thermogenic origins have been recorded in the Kumano Basin, but the thermogenic petroleum potential is poorly constrained because the regional‐scale geological architecture of the Nankai subduction zone is not well understood.

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日本西南部南海沉陷带的热质石油潜力

在日本西南海岸的熊野前盆地，从指出天然气水合物存在的地球物理调查以及对从钻孔和海底泥火山中回收的气体样本的地球化学分析，都可以推断出潜在的碳氢化合物存在。前臂盆地位于南海海槽的内部，菲律宾海板块在日本西南部向北俯冲。盆地序列不一致地覆盖了变形的增生棱镜复合体。在熊野盆地已记录了具有微生物和热成因的碳氢化合物，但由于对南开俯冲带的区域规模地质构造了解不多，致热的石油潜力受到的制约很小。