Fig. 5

Relationship between the distance from the epicenter to the nearest observation station and estimated M_w. Blue dots indicate the assumed M_w. Each box plot indicates the result of each fault ID. The yellow box indicates the result of the 2019 Yamagata-Oki earthquake. The green line indicates the theoretical envelope of M_w required to cause 5 cm horizontal displacement at the nearest station. The insert indicates the positional relationship between the station and the fault. We used the scaling law of Utsu (2001) to assume the size and calculated theoretical displacement according to Okada (1992). The small step in the green line near zero on the horizontal axis corresponds to a change in the displacement pattern at the ground surface, because the assumed fault has a finite size according to the scaling law