Earthquake Odds

Forecasting with probabilities

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

• With average gap $T$, the chance of a quake within $t$ years is $1 - e^{-t/T}$.
• Random events have no memory: a fault is never “overdue” in the Poisson model.
• Combine independent risks through the chance that none occur.

Steps

1. Not a timetable
2. Thirty years
3. Even odds
4. Overdue?
5. One in a hundred
6. Two faults