Submarine landslides constitute a major mass transport process from shallow‐ to deep‐sea and may have catastrophic impacts on both offshore infrastructure and coastal areas. Previous studies on submarine landslides have focused on triggering mechanisms and precondition perspectives, targeting limited numbers of short‐term landslide events. Consequently, few studies have addressed long‐term changes in landslide characteristics, including volume, direction, and timing. The areas studied herein are located on the continental slope facing the Japan Trench off the Shimokita Peninsula, northeast Japan, where a number of large‐scale translational‐type submarine landslide and accompanying unique dike structures have been identified in Pliocene to Recent deposits via 3D seismic data analysis. Here we developed a procedure for recognizing landslide deposits in 3D seismic data from the survey area, then investigated the 3D deposit distributions in detail. Because translational landslides preserve original structures, they can be used to estimate landslide volume. Parallel dike swarm features, which are interpreted as dewatering paths formed soon after landslide events, enable estimation of slide direction in time‐slice images. Such analysis also allows differentiation of landslide deposits from background sediments and estimation of landslide volume. Landslides exceeding 50 km³ in volume have occurred numerous times in the past 6 my. Landslides directions are observed from southwest to northeast over this entire period, whereas slides trending northwest to southeast started at ~ 2 Ma. Although the landslide sizes vary greatly, the average landslide volumes are roughly constant throughout Pliocene and Quaternary time. Such shifts in long‐term trends suggest a change in tectonics in the landslide source region. These unique long‐term records (over 6 my) are enabled by the specific conditions in the study region, which include translational landslides, parallel dike swarms, and monotonous lithology.

中文翻译：

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使用3D地震数据（日本下北田笔下的海底滑坡），在日本东北部下北半岛附近的上新世-第四纪沉积物中海底滑坡的滑动方向变化

海底滑坡是从浅海到深海的主要运输过程，可能对海上基础设施和沿海地区造成灾难性影响。先前关于海底滑坡的研究集中在触发机制和前提条件方面，针对的是短期滑坡事件的数量有限。因此，很少有研究涉及滑坡特征的长期变化，包括体积，方向和时间。本文研究的区域位于日本东北下沉北半岛对面的日本海沟对面的大陆斜坡上，在上新世至新近沉积物中通过3D地震发现了许多大型平移型海底滑坡及其伴随的堤防结构。数据分析。在这里，我们开发了一种在调查区域的3D地震数据中识别滑坡沉积物的程序，然后详细研究了3D沉积物的分布。由于平移滑坡保留了原始结构，因此可以用来估算滑坡量。平行堤防群的特征被解释为滑坡事件发生后不久形成的脱水路径，可以估算时间切片图像中的滑动方向。这种分析还可以区分滑坡沉积物与背景沉积物，并估算滑坡量。滑坡超过50公里 它们被解释为滑坡事件发生后不久形成的脱水路径，从而可以估计时间切片图像中的滑动方向。这种分析还可以区分滑坡沉积物与背景沉积物，并估算滑坡量。滑坡超过50公里 它们被解释为滑坡事件发生后不久形成的脱水路径，从而可以估计时间切片图像中的滑动方向。这种分析还可以区分滑坡沉积物与背景沉积物，并估算滑坡量。滑坡超过50公里³体积已经在过去6我发生了无数次。在整个时期内，从西南向东北观察到滑坡方向，而从西北向东南趋向的滑坡始于2 Ma。尽管滑坡的大小变化很大，但在上新世和第四纪整个时期内，平均滑坡体积大致保持不变。长期趋势的这种变化表明滑坡源区的构造发生了变化。这些独特的长期记录（超过6 my）是由研究区域中的特定条件决定的，包括平移滑坡，平行堤防群和单调岩性。