Fig. 4

Residuals between the observed recording rate and fitted functions. Parameters of the fitted functions are shown in Table 3. The recording rate of the datasets of M ≥ 4.0 (MA = 4, 6), M ≥ 4.5 (MA = 4) and M ≥ 5.0 (MA = 4) were not calculated because some of their consecutive events had the same ages and the denominator of equation 1 becomes zero