Difference in Slip Patterns Between Two Prehistoric Giant Earthquakes Along the Southern Kuril Trench

Abstract This study reveals different slip patterns of tsunami sources between two prehistoric giant earthquakes along the southern Kuril Trench, based on an integration of geological data and numerical simulations. The most recent giant earthquake occurred in the 17th century and its predecessor was in the 13th–14th century. The spatial distributions of the two associated tsunami deposits differ between the Nemuro and Tokachi regions along the Pacific coast of Hokkaido, northern Japan. We conducted detailed geological fieldwork in eastern Hokkaido to better estimate the tsunami inundation areas. These findings were then used for numerical simulations, and fault models of the 13th–14th‐century earthquake ( M w 8.6–8.7) were constructed. The fault model for the 17th‐century earthquake ( M w 8.8) is characterized by greater slip in the Tokachi‐oki segment. In contrast, the model for the 13th–14th‐century event suggests a greater slip in the Nemuro‐oki segment.