Fig. 4
Hypocenter distributions of the Wakayama swarm during the 2003–2020 period. a M ≥ 0 earthquakes. b M ≥ 1 earthquakes. c M ≥ 2 earthquakes. Dashed ellipses and arrows in (a) denote areas and lineaments with limited seismicity, respectively. Stars in (a–c) denote M ≥ 4 earthquakes. Focal depths are color-coded. d Focal mechanism solutions for the M ≥ 3 earthquakes that are reported in the JMA catalog