Reconstructing Anthropocene extreme flood events by using litter deposits

Coastal areas are densely populated and therefore vulnerable to the impact of flooding events induced by tsunami waves or storm surges. The flood risk has increased due to global climate change and an accelerated sea-level rise as observed during the most recent geological times (the Anthropocene). At the same time a concentration of settlements along the worldʹs coastlines is observed. Therefore, knowledge of maximum flooding levels during high-energy events is essential to improve the assessment of risk. We utilise wrack lines composed of litter as in situ physical marks made up of durable, solid matter of various compositions to delineate the maximum flooding level. These deposits may enclose information on production dates, used to precisely reconstruct the timing of the flooding. This approach allows an ultra-high resolution dating. We demonstrate the application of this efficient, fast and cheap method for the coastline of Oman bordering the Arabian Sea (Northern Indian Ocean). The area was recently affected by devastating tropical cyclones as well as tsunamis.