Submarine landslides are common geomorphological features of continental margins. Some of the largest submarine landslides occurred on low-angle (< 4°), sediment-starved margins, yet their preconditioning and trigger mechanisms are still largely unconstrained. The southwestern continental margin of the East Sea (between 37.5°N and 38.0°N), Korea, occupies a narrow shelf (< 10 km), is characterized by low sedimentation rates (~3–7 cm /ka) with an average gradient of less than 2°. Here, we investigate submarine landslides using newly collected datasets including multibeam echosounder (MBES), chirp sub-bottom profiler, multichannel seismic (MCS) data and ten piston cores. MBES data from the margin reveal at least four major submarine landslides initiated at depths of 400 m to over 600 m. These landslides left clear headwall scarps on the seafloor with reliefs reaching over ~130 m and extend for over 40 km. MCS data show that some of the failures have resulted in the complete disintegration of the failed mass, while others have resulted in the deposition of well-defined hummocky debris flows. Sediments recovered downslope of the headwall scarps contain slides and debris flow deposits and turbidites that are overlain by bioturbated hemipelagic layers. Radiocarbon dating from hemipelagic units overlying MTDs within the headwall scarps reveal that major failures occurred at ca. 11 to 19 ka, coinciding with the time of the Last Glacial Maximum (LGM) to early deglaciation. Since then, hemipelagic sedimentation has prevailed throughout the sediment starved slope. Slope stability analyses based on geotechnical properties of sediments indicate that all areas are stable under static, and even stable under loads derived from earthquakes in instrumental records, but there were probably earthquakes in pre-historical records (i.e., with a longer recurrence interval) of potentially significant larger magnitude. We suggest that the preferential occurrence of major failures adjacent to the major faults on the lower slope may ultimately be tectonic-controlled although other factors may have contributed as well. Our work shows that coarse-grained clastic sediments are abundant in the shallow subsurface and that these higher-permeability units, often identified as weak layers, would focus fluid flow and could act as slip planes for slope failure. Our data also indicate that tectonic steepening and gas charging are other key parameters for controlling instability in sediment-starved margins.

海底滑坡是大陆边缘的常见地貌特征。一些最大的海底滑坡发生在低角度（<4°），缺乏沉积物的边缘，但是它们的预处理和触发机制仍然没有受到很大的限制。韩国东海的西南大陆边缘（介于37.5°N和38.0°N之间）占据一个狭窄的陆架（<10 km），其特征在于沉积速率低（〜3–7 cm / ka）且平均梯度小于2°。在这里，我们使用新收集的数据集（包括多波束回声测深仪（MBES），线性调频地下底部轮廓仪，多通道地震（MCS）数据和十个活塞芯）来调查海底滑坡。来自边缘的MBES数据显示，至少有四个主要的海底滑坡始于400 m至600 m以上的深度。这些滑坡在海底留下了清晰的顶壁陡坡，浮雕达到了约130 m，延伸了40多公里。MCS数据显示，某些失败导致失败的团块完全崩解，而另一些导致明确的山岗泥石流沉积。顶壁陡坡恢复的沉积物的下坡包含由生物扰动的中流层覆盖的滑坡，泥石流沉积物和浊石。覆盖在头壁陡坡中MTD上的半地中海单元的放射性碳年代测定表明，主要的破坏发生在约200米处。11至19 ka，与最后一次冰河期（LGM）到早期冰消的时间相吻合。从那时起，在沉积物匮乏的整个斜坡上都普遍存在半海相沉积。根据沉积物的岩土工程特性进行的边坡稳定性分析表明，所有区域在静态情况下都是稳定的，甚至在仪器记录中的地震荷载作用下也是稳定的，但是史前记录中的地震（即复发间隔较长）可能存在地震。潜在的较大幅度。我们认为，虽然其他因素也可能对下斜坡的主要断层附近的主要断层的优先发生产生了最终的构造控制作用。我们的工作表明，浅层地下富含大量的碎屑碎屑沉积物，这些较高渗透率的单元（通常被识别为薄弱层）将集中流体流动，并可以作为滑坡来破坏边坡。