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Earth, Planets and Space

Table 3 Statistics of clusters with 200 or more foreshocks and aftershocks

From: Characteristics of foreshock activity inferred from the JMA earthquake catalog

Group Mainshock Mc Foreshock Aftershock Background ΔAIC
ID Lat (°) Lon (°) M N (≥ Mc) b σ b N (≥ Mc) b σ b N (≥ Mc) b σ b  
(a) Mc = MAXC + 0.2 for the entire magnitude range
 1 31.84 130.29 4.2 1.2 131 0.95 0.09 140 1.15 0.10 4171 1.04 0.02 0.5
 2 34.96 139.18 5.9 1.3 153 0.50 0.03 155 0.59 0.03 3234 0.86 0.01 0.3
 3 36.33 137.63 5.6 1.7 92 0.75 0.08 87 0.90 0.09 2826 0.85 0.02 − 0.6
 4 35.28 135.93 5.2 1.3 110 1.02 0.12 105 0.98 0.09 4055 0.89 0.01 − 1.9
 5 42.50 140.83 4.9 1.8 65 1.12 0.13 71 1.16 0.11 37 0.80 0.11 − 2.0
 6 43.74 144.70 4.8 1.6 42 2.53 0.25 56 1.06 0.13 360 0.93 0.06 14.9
 7 37.30 136.84 5.3 2.7 71 0.75 0.08 23 0.83 0.12 19 0.68 0.12 − 1.9
 8 34.96 139.13 5.1 1.4 78 1.11 0.10 89 0.87 0.09 5362 0.76 0.01 0.5
 9 36.95 140.67 7.0 3.2 30 0.57 0.10 114 0.63 0.05 9 1.04 0.24 − 1.8
 10 32.75 130.76 7.3 3.1 50 0.69 0.10 126 0.72 0.06 166 1.00 0.07 − 1.9
 11 31.38 130.62 5.3 1.8 27 1.02 0.20 34 1.16 0.15 275 1.15 0.06 − 1.8
(b) Mc = Mmain – 3.5 for Mmain ≥ 5.5
 2 34.96 139.18 5.9 2.4 47 0.82 0.11 31 0.96 0.12 3234 0.86 0.01 − 1.5
 3 36.33 137.63 5.6 2.1 45 0.74 0.11 40 1.00 0.15 2826 0.85 0.02 0.0
 9 36.95 140.67 7.0 3.5 21 0.59 0.12 81 0.71 0.06 9 1.04 0.24 − 1.4
 10 32.75 130.76 7.3 3.8 15 0.62 0.18 42 0.89 0.15 166 1.00 0.07 − 0.5
  1. Lat., Lon., and M indicate the latitude, longitude, and magnitude of the mainshock, respectively. Mc indicates the completeness magnitude. The parameters, b and σ b , are the b-value and its uncertainty, respectively. ΔAIC indicates the difference of AIC values (Utsu 1999). a Mc was chosen as MAXC + 0.2 for the entire magnitude range, b Mc was chosen as Mmain − 3.5 for Mmain ≥ 5.5
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