An event deposit is preliminarily found using grain size changes in a geologic stratum along with multiple other proxies for environmental changes (Watanabe et al., 2020) . Additionally, geochemical analysis is widely used to estimate the source of the sediments (Minoura and Nakaya, 1991; Chagué-Goff et al., 2017) . Following recent major subduction zone earthquakes, the analysis of tsunami deposits has been increasing to help clarify such geochemical features (Chagué-Goff et al., 2017;

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... et al., 2020) . The geochemical signatures of tsunami deposits from the southwestern coasts of Spain, New Zealand, the Hawaiian Islands, Mexico and northeastern Japan have also been studied (