Geography & Earth
Intermediate

Richter Magnitude

Earthquake magnitude from seismograph amplitude.

Formula

M=log⁡10AA0M = \log_{10}\frac{A}{A_0}

Variables

AMeasured amplitude
A_0Reference amplitude

Example

Each whole step up the Richter scale means 10× larger ground motion.

Did You Know?

The Richter scale is logarithmic — each whole step is 10× the shaking and about 32× the energy released.

earthquakerichterseismology