Estimation of tsunami sources of the 17th-century deposits in Northern Hidaka, Western Hokkaido, Japan based on sediment transport modeling

Sediment transport modeling is a powerful tool for identifying wave sources of past tsunami deposits because it can reproduce not only the thickness distribution but also the sediment features such as grain size. The magnitude of past giant earthquakes along the Kuril Trench has been estimated based on the along-coast distribution of tsunami deposits of similar age. However, the extent to which these sand layers share a common origin remains unclear, introducing significant uncertainty into magnitude estimations. The interpretation of the 17th-century tsunami deposits is especially complex because the tsunami sources have multiple candidates around the same time as the volcanic tsunami from Mt. Hokkaido Komagatake eruption and historical earthquakes with sources near the Japan Trench. Multiple tsunami deposits have been found in Kabari, northern Hidaka, Hokkaido, and their tsunami sources are expected to provide a significant constraint on the tsunami magnitude. We reproduce two layers of tsunami deposits around the 17th century with sediment transport modeling using possible tsunami source candidate models. The Mt. Komagatake collapse and Kuril Trench earthquake models reproduce the two layers of tsunami deposits, indicating the tsunami distributions along the Pacific coast of Hokkaido are reproduced without Mw > 9 earthquake models.