Fig. 2
From: Streak and hierarchical structures of the Tohoku–Hokkaido subduction zone plate boundary
Moderate-size repeating earthquakes in the Kushiro-Oki and Naka-Oki regions. a Earthquake distribution in the Naka-Oki region. The center and size of each circle represent the centroid location and estimated source size, respectively. The red, blue, cyan, and yellow circles indicate the group M, A, B, and C events, respectively. Gray circles show ungrouped events. b Magnitude–time diagram of the group M, A, B, and C events. c Earthquake distribution in the Kushiro-Oki region. The red and blue circles indicate group M and D events, respectively. d Magnitude–time diagram of the group M and D events