Table 2 Contingency table of evaluated foreshock probabilities for mainshocks with magnitudes larger than their largest foreshock magnitudes + 0.4 and actual portion of foreshocks with 90% binomial proportion confidence interval in seismic clusters of size N = 2, 5, 10, 20
From: Cluster-based foreshock discrimination model with flexible time horizon and mainshock magnitudes
Foreshock probability | 0–10% | 10–20% | 20–30% | 30–40% | Total | |
|---|---|---|---|---|---|---|
N = 2 | All clusters | 1045 | 203 | 5 | 0 | 1253 |
Foreshock clusters | 69 | 28 | 1 | 0 | 98 | |
Portion of foreshocks (90% CI) | 7% (5–8%) | 14% (10–18%) | 20% (1–66%) | N/A | 8% | |
N = 5 | All clusters | 196 | 36 | 8 | 2 | 242 |
Foreshock clusters | 16 | 5 | 1 | 2 | 24 | |
Portion of foreshocks (90% CI) | 8% (5–12%) | 14% (6–27%) | 13% (1–47%) | 100% (22–100%) | 10% | |
N = 10 | All clusters | 75 | 11 | 5 | 0 | 91 |
Foreshock clusters | 6 | 5 | 1 | 0 | 12 | |
Portion of foreshocks (90% CI) | 8% (4–15%) | 45% (20–73%) | 20% (1–66%) | N/A | 13% | |
N = 20 | All clusters | 36 | 2 | 2 | 3 | 43 |
Foreshock clusters | 2 | 1 | 1 | 0 | 4 | |
Portion of foreshocks (90% CI) | 6% (1–16%) | 50% (3–97%) | 50% (3–97%) | 0% (0–63%) | 9% | |