#earthscience #physics #seismology

The Richter scale is a measure of the strength of [[Earthquake|earthquakes]]. 

It was developed by Charles Richter in collaboration with Beno Gutenberg in 1935.

## Scale
The scale is logarithmic, which means that each whole number increase in magnitude corresponds to a tenfold increase in the [[Механические колебания|amplitude]] of the earthquake, and a 31.6 increase in the energy released by the quake.

| Richter magnitude | Description |
| ----------------- | ----------- |
| 1.0 - 1.9         | Micro       |
| 2.0 - 2.9         | Minor       |
| 3.0 - 3.9         | Slight      |
| 4.0 - 4.9         | Light       |
| 5.0 - 5.9         | Moderate    |
| 6.0 - 6.9         | Strong      |
| 7.0 - 7.9         | Major       |
| 8.0 - 8.9         | Great       |
| 9.0 - 9.9         | Extreme     |

## Formula
$$\LARGE M_L = \log_{10}{\frac{A}{A_0}}$$where $\LARGE M_L$ - local magnitude, A is the maximum ampltiude (in mm) of a seismic wave as recorded by the [[Wood-Anderson seismograph]], and $\LARGE A_0$ is the amplitude of a standard wave at 100km from the earthquake epicenter.