The seismic activity of an inclination from the upper right of the figure (east)to the lower left (west) occurs along the subducting Pacific Plate. The distribution of these earthquakes shows that the Pacific Plate is subducting beneath the Hokkaido region. Also, in C, seismic activity in the southern Hidaka Mountains at a depth of 20-40 km can be seen a little to the right of the center of the figure.

[Compiled from data from Hokkaido University]