Organic-geochemical proxy for tracing recent and historical Tsunamis in time and space

日本的沉积档案保存了超过人类记录的千年海啸沉积物。仅从仪器记录开始，就有300多起大大小小的海啸被记录下来，这些海啸是由当地地震引起的。再往前走，沿着日本海岸线竖立着数百个这样的石碑，其中一些可以追溯到1150多年前，在公元869年的日根海啸之后。有机化合物的保存潜力在历史、特别是古海啸沉积的研究中显示出巨大的潜力。这种有机地球化学标志已被证明是研究现代海啸沉积物和探测超出视觉识别极限的沉积物的宝贵工具。但基于高保存潜力和具有高来源特异性的指示性化合物群，有机标志物在历史和古海啸研究中也有重要贡献。因此，本研究的目的是结合标准参数（粒度、XRF、微古生物学、测年），在多代理方法中建立适当和可靠的自然有机指标，以主要识别沉积档案中的历史和古海啸。更一般地说，通过这项研究，我们进一步的目标是将研究领域的跨学科领域（即海啸研究，有机地球化学和沉积学/微古生物学方法）与发生在最后40%的洪水中的过程（例如，运输，沉积，海啸反冲分布）结合起来，以获得更全面的见解，这些过程今天几乎仍然未知，因为它们超出了可见的沙质海啸沉积物的限制。

Japanese sedimentary archives preserve millenarian tsunami deposits beyond human records. Since the beginning of instrumental records alone, over 300 tsunamis – large and small– have been documented from local earthquakes. Further on, hundreds of these stone tablets erect along the Japanese coastline, some dating back to more than 1150 years ago in the wake of the 869 CE Jogan tsunami. For the investigation of historic-, but especially to identify paleo-tsunami deposits from the sedimentary record, organic compounds show great potential based on their preservation potential. Such organic geochemical markers have been proven a valuable tool to investigate modern tsunami deposits and to detect those deposits beyond the limit of visual recognition. But based on high preservation potentials and indicative compound groups with high source specificities organic markers contribute also significantly to historical and paleo-tsunami research. Consequently, the aim of this study is the establishment of appropriate and reliable natural organic indicators combined with standard parameters (grain size, XRF, micropaleontology, dating) in a multi-proxy approach to identify historic- and paleo-tsunamis in sedimentary archives in principal. More generally, through this study, we further aim to combine interdisciplinary fields of research areas (i.e., tsunami research, organic geochemistry, and sedimentological/micropaleontological approaches) with the intention to gain a more holistic insight into processes (e.g., transport, deposition, tsunami backwash distribution) that occur in the last 40% of the inundation, which remain today virtually unknown, as they lay beyond the limit of visibly recognizable sandy tsunami deposits.