Fig. 2

Plots of the cumulative number (a, d, g), the number (i.e., the rate of occurrence) (b, e, h), and the change in the number (i.e., the change in the rate of occurrence) (c, f, i) of M ≥ 3 earthquakes as a function of relative time (days) to the M7.3 quake (vertical solid line). a–c seismicity in the entire area, d–f seismicity in the northern area (higher than 32.72° in latitude), and g–i seismicity in the southern area (lower than 32.72° in latitude). We used a time window of 0.08 days. See also Fig. A2 in Additional file 1 for other time windows of 0.05 and 0.10 days. Vertical dashed lines indicate relative times 0.98 and 0.67 days to the M7.3 quake