9:45 AM - 10:00 AM
[MIS25-04] Trench and coring survey of the tsunami deposits in the coastal area along the Wakasa Bay, Takahama, Fukui Prefecture.
Keywords:tsunami deposits, Wakasa Bay area, Takahama, coastal plain
Some sand layers which might be formed by the tsunami event were found in the peaty deposits under the coastal lowland in Sonobe area, Takahama-cho, Fukui Prefecture. This time, we mainly investigate the shallow sand layers than 1m.
The coring and trench survey in this area shows that the sand layers are distributed more than 500m to the inland form the shore. The sand include grains of the well-rounded rock fragments and organic remains such as shell, foraminifera and spine of the sea urchin, which are a lot included in the coastal sand of this area. In addition, the sand layers eroded the peaty sediments at the base, and include the rip-up clast of them. The radiocarbon dates of the peaty sediments below and above the sand layer show that the layers deposited between the 14th and the 16th century.
These data shows that the sand layers might be formed by ancient tsunami event of 16th century recorded in the historical documents in this area.
The coring and trench survey in this area shows that the sand layers are distributed more than 500m to the inland form the shore. The sand include grains of the well-rounded rock fragments and organic remains such as shell, foraminifera and spine of the sea urchin, which are a lot included in the coastal sand of this area. In addition, the sand layers eroded the peaty sediments at the base, and include the rip-up clast of them. The radiocarbon dates of the peaty sediments below and above the sand layer show that the layers deposited between the 14th and the 16th century.
These data shows that the sand layers might be formed by ancient tsunami event of 16th century recorded in the historical documents in this area.