The two rows of the seismic activity that incline downward from the upper right of the figure (east) to the lower left occur on the upper surface of the subducting Pacific Plate and within the plate. From the distribution of these earthquakes, it is apparent that the Pacific Plate is subducting under the Kanto region. Also, the seismic activity which is inclining toward the left and right (east and west) from the Izu Peninsula, as shown in the profile chart D and E, is along the subducting Philippine Sea Plate. Refer to Fig. 5-4 for a, b, and c.
[Compiled from data from the National Research Institute for Earth Science and Disaster Prevention]