The 684 Hakuho earthquake took place in Japan in 684. The earthquake was described in the history book Nihon Shoki (8th century). The earthquake took place on 29 November, 684, in year 13 of the reign of Emperor Tenmu (Tenmu period). It caused the under-sea inundation of approximately 10 km2 (3.9 sq mi) of rice fields. Regarding the flooding, the Nihon Shoki reports that the local people had never experienced a disaster of this type. A corresponding Tōkai earthquake may have occurred in 684, but is not clearly recorded in primary sources. The next known Nankai earthquake took place in 887.