Fig. 9
From: Depth variation of seismic moment and recurrence interval in Japan
Distribution of the logarithm of the seismic moment rate (logc) obtained by the MMSI method and compared with the hypocenters of recorded M5 + earthquakes from 1997 to 2015 at depths shallower than 60 km using a threshold of 10,000 events for each seismically dense sphere. The color indicates the seismic moment rate (logc) value in and around Japan in this study. The squares and triangles indicate that the seismically dense spheres are unable to calculate the MMSI due to insufficient foreshocks before (squares) or after (triangles) December 31, 1998, while the circles indicate the seismically dense spheres with sufficient foreshocks to calculate the MMSI. The number inside the squares, triangles, and circles indicates the magnitude of M5+ earthquakes. The size of the squares and triangles is fixed. The radii of the circles indicate the ratio value of the smallest seismic moment rate of the foreshocks versus the seismic moment rate of the M5+ mainshock. Small radii of circles indicate that the M5+ earthquake (usually landward) occurred immediately after a large seismic interval or the foreshocks are associated with a small seismic interval