EAGER: Geologic Evidence of Tsunamis originating from the Japan Trench's Southern Segment

在2011年东北冲海啸之后，对日本海沟破裂情景进行建模的研究确定了不确定性区域，特别是沿着南段。通过定位和绘制史前海啸沉积物，可以大大提高这些地震模型的准确性和对日本南部海沟沿着断层运动的理解。海啸的记录是从它们留下的沉积物中发展出来的，通过扩大可供研究的事件的年龄范围，提高了我们的理解。这个EAGER研究项目由宾夕法尼亚大学和日本地质调查局的科学家进行，目的是找到过去海啸起源于日本海沟南段的地质证据，迄今为止，这些证据仍然没有记录。本研究将采用最先进的岩石、生物和年代地层学技术，调查日本千叶地区的海滩山脊和沿海池塘。该研究具有高度的探索性，因为迄今为止，在该地区已经发现了古海啸的地质证据。2011年东北冲发生了意外的9.0级海啸，这突出了了解源自日本海沟的海啸的时间和规模的重要性。尽管产生了最大的地震仪器记录，但对日本海沟，特别是东京附近的南段，知之甚少。确定海啸引发地震的复发间隔，改善了对世界上最大的都市区-大东京地区自然灾害的评估。这项研究将提供有关长期地震模式不确定性的重要新信息，不仅是日本海沟，而且还包括北美太平洋沿岸、智利和印度尼西亚等其他地区。

In the wake of the 2011 Tohoku-oki tsunami, studies modelling rupture scenarios for the Japan Trench have identified areas of uncertainty, particularly along the southern segment. The accuracy of these seismic models and the understanding of fault movement along the southern Japan Trench can be greatly improved by locating and mapping prehistoric tsunamis deposits. Records of tsunamis developed from the sedimentary deposits they leave behind, improve our understanding by expanding the age range of events available for study. This EAGER research project, carried out by scientists from the University of Pennsylvania and the Geological Survey of Japan, aims to locate geologic evidence of past tsunamis originating from the southern segment of the Japan Trench, which to date remains undocumented. The study will investigate the beach ridges and coastal ponds of Chiba region of Japan using the state-of-the-art litho-, bio-, and chronostratigraphical techniques. The research is highly exploratory in nature since, as of yet, geologic evidence of paleo-tsunamis in this region has been found.The importance of understanding the timing and magnitude of tsunamis originating from the Japan Trench was highlighted by the unexpected Mw 9.0 Tohoku-oki event in 2011. Despite generating the largest instrumental record of an earthquake, very little is known about the Japan Trench, particularly its southern segment near Tokyo. The establishment of a recurrence interval for tsunami generating earthquakes improve assessments of natural hazards to the Greater Tokyo Area, the largest metropolitan area in the world. This research will provide important new information concerning the uncertainty surrounding long-term earthquake patterns, not only for the Japan Trench, but also for other locations such as the Pacific coast of North America, Chile and Indonesia.