Subsidence and a change of depositional environment by the 1662 Hyuganada earthquake in southern Miyazaki Plain

Ikuta, Masafumi; Sato, Yoshiki; Niwa, Masakazu   ; Kamataki, Takanobu*; Kurosawa, Hideki*; Takatori, Ryoichi*

A lot of great earthquakes have caused in the Hyuganada and the Nankai trough. According to historical records of documents, the 1662 Kanbun Hyuganada earthquake, had caused serious damage and natural calamity. Around the estuary of the Kaeda-gawa River, the tsunami had reached to about 4 to 5meter height, and ground subsided about 1meter.Shimayama region which is located in the estuary of the Kaeda-gawa River, was formed an intrusive arm of the sea occurred by this subside event. Some historical records of documents and landscape pictures show that the 1662 Kanbun Hyuganada earthquake changed topography and depositional environment in this area extremely. However, there is no case study of this evidence. So, we did multiple borings in the abandoned lagoon sediments and tried to restore depositional environment around the subsided area by some analysis methods such as microfossils and chemistry to use boring cores. These results will be presented in this session.