Earthquake Statistics

n(t) = K/(t+c)^p — Omori-Utsu law (1894/1961): aftershock rate. p ≈ 0.9–1.2 universally.
log₁₀ N(≥M) = a − bM — Gutenberg-Richter relation. b ≈ 1 globally (Richter 1956).
ΔE ∝ 10^(1.5M) — energy release. M 7.0 releases ~1000× more energy than M 5.0.