The M9.3 2004 Sumatra and M9.0 2011 Tohoku earthquakes and tsunamis had devastating consequences for the adjacent heavily populated coasts. They had large shallow coseismic slip that reached the trench, which is thought to be a key factor in generating the huge tsunamis. The sedimentary record contains unique spatial and temporal information on the effects of megathrust earthquakes. It can provide a better understanding of earthquake-related tectono-sedimentary processes and of the earthquakes themselves. We present new results obtained from high-resolution multibeam bathymetry, subbottom profiles acquired with Parasound and ten, 10 m long piston cores recently collected from the Japan Trench margin during R/V Sonne SO251 expedition. We identify the 2011 Tohoku event-deposit extending for ~250 km along the Japan Trench basins from the enrichment and concentrations of short-lived radioisotopes (excess) xs²¹⁰Pb, ¹³⁷Cs and ¹³⁴Cs in all ten cores. The high enrichment of xs²¹⁰Pb points to surficial sediment remobilization as the main source. In three cores from the northern, central and southern segments of the Japan Trench, for the first time, we identify sediment remobilization by its ^87/86Sr, εNd and Pb isotope signatures and the composition and texture of the sediment. With this new approach, we fingerprint older sedimentation events, potentially linked to earthquakes and infer processes responsible for their deposition. Thick, acoustically transparent and homogeneous units we name “homogenites”, characterize these event deposits. Physical, geochemical and acoustic properties link homogenites to the 2011 Tohoku and previous earthquakes. We propose a multi-stage entrainment and depositional process related with both the high frequency and the exceptionally large low frequency and long duration motions expected from ruptures of the shallow megathrust below the compliant outer upper-plate. These large long-period motions could propagate along the outer upper plate beyond the rupture zone and could generate widespread entrainment of surficial sediment.

2004年苏门答腊岛M9.3级地震和2011年东北部M9.0级地震和海啸对邻近人口稠密的海岸造成了毁灭性后果。他们有大的浅同震滑移到达海沟，这被认为是产生巨大海啸的关键因素。沉积记录包含有关巨推力地震影响的独特时空信息。它可以更好地了解与地震有关的构造沉积过程和地震本身。我们介绍了高分辨率多光束测深法，用Parasound采集的下层剖面以及最近在R / V Sonne期间从日本海沟边缘收集的十个10m长的活塞芯所获得的新结果。SO251探险队。我们从所有十个岩心中短寿命放射性同位素（过量）xs ²¹⁰ Pb，¹³⁷ Cs和¹³⁴ Cs的富集和浓度中，确定了沿日本海沟盆地延伸约250 km的2011年东北事件矿床。xs ²¹⁰ Pb的高富集表明表层沉积物迁移是主要来源。在日本海沟北部，中部和南部部分的三个^岩心中，我们首次通过其^87/86识别了沉积物^迁移Sr，εNd和Pb同位素特征以及沉积物的组成和质地。通过这种新方法，我们可以对较旧的沉积事件进行指纹识别，这些事件可能与地震有关，并推断出造成沉积的原因。这些事件沉积物的特征是厚的，透声的，均质的单元，我们称之为“均质岩”。物理，地球化学和声学特性将均质与2011年东北和以前的地震联系在一起。我们提出了一个多阶段的夹带和沉积过程，该过程与高频率以及异常大的低频和长时程运动有关，这是由顺应性外部上板下方的浅层巨推力破裂引起的。