Submarine landslide deposits have been recognized in the downslope of a mega-splay fault of the Kumano-nada continental slope. A sediment core was recovered in the mega-splay fault area to find recent slope failures. The youngest mass transport deposit was identified 1.7 m below the seafloor in the study area based on physical properties, radiocarbon dating, and sedimentary and deformation structures. Kinematic analysis of the ductile deformation structure suggests that the mass transport deposit layer came from the steep slope of the hanging wall of the mega-splay fault. This observation agrees with the major scarp collapse being limited mainly to the source area. However, the mega-splay fault in the source area is considered to be currently inactive. Based on the subseafloor structure in the study area, ridge subduction appears to be indirectly destabilizing the slope sediment on the accretionary prism, creating the conditions for submarine landslides on the forearc slope.

中文翻译：

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西日本熊野滩大陆坡海底滑坡的控制因素


在熊野滩大陆坡巨型张开断层的下坡中发现了海底滑坡沉积物。在巨型张开断层区域发现了沉积岩芯，以发现最近的斜坡破坏。根据物理性质、放射性碳测年以及沉积和变形结构，在研究区域海底以下 1.7 m 处发现了最年轻的物质运输矿床。韧性变形结构的运动学分析表明，质量输送沉积层来自大张断层上盘的陡坡。这一观察结果与主要陡坡塌陷主要局限于源区的观点一致。然而，源区的巨型扇状断层被认为目前处于非活动状态。根据研究区的海底结构，洋脊俯冲似乎间接破坏了增生棱柱上的斜坡沉积物的稳定性，为弧前斜坡上的海底滑坡创造了条件。