<Dl> <Dd> E s ≈ M 0 / (2 × 10 4) (\ displaystyle E_ (s) \ approx M_ (0) / (2 \ times 10 ^ (4))) </Dd> </Dl> <Dd> E s ≈ M 0 / (2 × 10 4) (\ displaystyle E_ (s) \ approx M_ (0) / (2 \ times 10 ^ (4))) </Dd> <P> (where E is in Joules and M is in N-m), Kanamori approximated M by </P> <Dl> <Dd> M w = (log ⁡ M 0 − 9.1) / 1.5 (\ displaystyle M_ (w) = (\ log M_ (0) - 9.1) / 1.5) </Dd> </Dl>

The magnitude scale is a measure of energy released