The Pacific coast of Atsumi Peninsula has been repeatedly damaged by tsunamis. The characteristics of event deposits in the coastal lowland are discussed based on sedimentological and historical records. Sand layers, 1-4 cm thick, were found approximately 30 cm below the surface in three sediment cores and a test trench. Grain size analysis by sieving and settling tube methods and roundness analysis suggest that sand grains of the sand layer were originated mainly from beaches. On the basis of the inland sediment-transport distance, radiocarbon age, mixing of beach-sand and river-sand, and historical records, it was estimated that the sand layers were formed by the inundation process of a historical tsunami in the Edo period.
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