Geological evidence discovered in 2013 suggested that an earthquake along the Manila Trench caused a tsunami that inundated the coastal areas of China. Geological surveys done by Chinese geologist discovered large boulders on Dongdao, a small island located in the middle of the South China Sea, transported by a gigantic wave almost 600 ft inland. Dating of organic remains preserved in the tsunami layer suggested that the tsunami happened sometimes around the year 1090. However, the extent of the tsunami remained unclear. Excavations at archaeological sites on the island of Nan’ao, just off the coast of Guangdong Province on mainland China, revealed sediments deposited by a tsunami here. Embedded in the tsunami sediments a research team from the University of Science and Technology and the East China Normal University found fragments of pottery dated to the Song-Dynasty (960-1279), suggesting that the tsunami that inundated Nan’ao island was the same that transported the boulders up the shores of Dongdao island. A shipwreck with 20,000 Chinese coins on board also dates in the same period, suggesting that the tsunami hit and devastated the entire coast surrounding the South China Sea.
Nowadays the coastal region of Guangdong is one of the most densely populated areas of China and the South China Sea is surrounded by important industrial centers and large cities like Hongkong, Macau, Xiamen and Quanzhou. Urban planning, so the research, should consider the risk of a large tsunami in the area and plan ahead. The scientists are especially worried about existing nuclear plants along the coast, like in Fuqing or in Daya Bay, and the construction of new ones, like one in Taishan. The earthquake and tsunami that struck Japan in 2011 showed how prone to a disaster nuclear plants, like the one from Fukushima, can be.