New evidence for the 1000-year-old tsunami in the South China Sea

A giant tsunami occurred in the South China Sea (SCS) approximately a thousand years ago, and various types of tsunami deposits were identified on the Xisha Islands, coastline of South China and Badoc Island, the Philippines. However, little is known about the extent of the affected SCS coastlines and the history of other giant tsunamis. Here, we identify tsunami deposits in the coastal sediment of Dongshan Bay, northeastern SCS. The tsunami deposit contains marine shell debris and coarse quartz grains, distinct from the muddy deposits in the upper and lower layers. Geochemical proxies, including Sr/Ba, Ca, Ti, Ca/Ti, and total organic carbon, indicate the marine intrusion of the event deposit. Radiocarbon ages of shells of the event layer are 970-1179 and 1137-1462 cal. yr BP (2 sigma range of calibrated 14C age). We suggest that the event layer was possibly deposited by the 1000-year-old tsunami. We found onshore tsunami deposits further north than previous studies, providing a new research example of onshore tsunami deposits and a reference for tsunami deposit research and tsunami disaster prevention.