# Richter scale

The **Richter scale** is a scale to measure the amount of seismic energy released by an earthquake. This scale was designed by Charles Richter in 1935 at California Institute of Technology to compare the strength of earthquakes. The scale is a base-10 logarithmic scale where each whole number increment is an increase of power by 10x. That is, going from a 4.3 earthquake to a 5.3 is 10x more powerful and going from a 4.3 to a 6.3 earthquake is 100x more powerful.

To find out how much more powerful one earthquake is from another, subtract the two numbers and take the inverse log of the result. Going from a 7.9 earthquake to an 8.0 earthquake you get 8.0 - 7.9 resulting in 0.1. The inverse log of 0.1 is 1.2589... so the increase in magnitude is approximately 1.25x.

The amount of energy released is about 31x more with each whole number increase. To make the ground shake 10x more, you need to release 31x more energy. This is only useful for comparing with explosions and other natural phenomena. For example, a tornado releases about the same amount of energy as a 4.5 magnitude earthquake and a small nuclear explosion is similar to a 4.0 magnitude earthquake.^{[1]}

## See also

- Earthquake
- Natural disaster
- Seismic
- Loma Prieta Earthquake
- San Francisco 1906 earthquake and fire
- Epicenter
- California
- Emergency links