Aftershocks & Omori’s Law

A power law in time

An interactive lesson with 6 steps, about 5 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• Omori’s law: aftershock rate $n(t) = K/(t + c)$, a power law in time.
• Each factor of ten in time brings the same number of aftershocks.
• Båth’s law: the largest aftershock is about 1.2 magnitudes below the main shock.

Steps

1. Shaking that slowly fades
2. Day ten
3. Equal shares of a log scale
4. Does it ever stop?
5. Count them
6. The biggest aftershock