[M-IS23_2PM1] tsunami deposit

[MIS23-20] Preliminary study for evidence of tsunami deposits from Holocene sediments along the coastal area of the Wakasa Bay.

*Hirofumi YAMAMOTO¹, Atsushi URABE², Naohiro SASAKI¹, Yasuhiro TAKASHIMIZU³, Kyoko S. KATAOKA² (1.Fukui University, 2.NHDR, Niigata University, 3.Niigata University)

Keywords:Wakasa Bay area, coastal plain, tsunami deposits, Holocene

This study reconstructed the Holocene sedimentary environment and researched the distribution of possible tsunami deposits in the coastal plain along the Wakasa Bay area in Fukui Prefecture.Around the Wakasa Bay Area, some historical documents suggested the tsunami event of AD 1586 (Tensho Tsunami), but no sedimentary evidence of this event was reported from this area. So, we carried out reconnaissance along the coastal area of the Wakasa Bay to find the natural lowlands facing sandy beach that are suitable for tsunami deposit reservation. For example, at the Sonobe area in Takahama-cho, a low land behind the beach ridges was said to have been a marshes area, and our preliminary study show that this area had shifted from inner bay environments to marshes area about 3000 years ago. At these places, we study the Holocene sediment using the Geoslicer of 5 meters long.