(5)The Earthquake in Beppu Bay (September 4, 1596, M 7.0)
The focal region is thought to have been in the southeast of Beppu Bay. The earthquake caused extensive damage on the shores of the bay. Many normal faults run in a roughly east-west direction on the floor of the bay, forming a trench sunken in the central part of the bay that stretches roughly east to west. It is hypothesized that this earthquake may have occurred a normal fault forming this trench. Avalanches and landslides occurred at Mt. Takasaki, Hiji, Yufuin, and Saganoseki, and houses were buried. There was also a tsunami that washed away many houses and fields. The tsunami began with low tide, and struck the coast of the bay somewhat later. Reports indicate that a 4-meter-high tsunami struck the port town of Okinohama, about 4 km from Funai, the present-day Oita City. The destruction in Funai was devastating, remained houses were only 200 out of 5,000 there. In addition, about 80% of Uryu Island sunk. This island was about 12 km in circumference and was located in Beppu Bay about 400 m to 500 m from Oita City. A total of 708 fatalities were reported on the island. The historical account that contained the name Uryu, however, only came to light more than 100 years after the earthquake. Recent topographical studies of the sea floor have not been able to determine the island's location, and there are doubts about the reliability of the manuscript.
These are the same types of earthquakes that occur on land in shallow areas. However, in cases where the focal region is located at sea, a tsunami sometimes occurs and brings about heavy damage.