Relationship between the maximum extent of tsunami sand and the inundation limit of the 2011 Tohoku-oki tsunami on the Sendai Plain, Japan

Abstract

This paper focuses on the relationship between the maximum extent of sandy tsunami deposits and inundation distance of the 2011 Tohoku-oki tsunami. Inundation limits of the Tohoku-oki tsunami were assessed over seven shore-normal transects along the Sendai Coastal Plain. Inundation distances were found to range from 0.6 to 4.0km. At the maximum extent of the tsunami deposit, the sand unit ranged in thicknesses from 0.1 to 4.0cm. The maximum limit of the ≥0.5cm thick sand layer extended to over 90% of the inundation distance where the inundation distance was less than 2.5km. This observation is consistent with previous studies that examined characteristics of recent tsunami events that had inundation distances of at least 2km. The maximum limit of the ≥0.5cm thick sand layer extended to 3km (57–76% of the inundation distance) where the inundation distance was more than 2.5km. Our results are important for estimating paleo-tsunami inundation distances based on the landward extent of sand deposits and valuable for the assessment of future tsunami risks in other coastal areas in the world, which have been devastated by huge tsunamis in the past.