BTW Sandpile

Self-organized criticality — avalanches with power-law size distribution

Avalanche sizes (log-log)
Grains: 0
Avalanches: 0
Last size: —
Max size: 0
1
4
The BTW sandpile (Bak, Tang, Wiesenfeld 1987) is the canonical model of self-organized criticality. Grains are added randomly; sites with slope ≥ K topple, distributing to neighbors. The system self-organizes to a critical state — no parameter tuning needed — producing avalanches of all scales following a power law P(s) ∝ s−τ with τ ≈ 1.0–1.5. Sandpile universality class extends to earthquakes, solar flares, and neural activity.