The earthquake scale most commonly referred to is the Richter scale. It measures the magnitude of an earthquake, which is the amount of energy released during the event. The Richter scale is a base-10 logarithmic scale, meaning each whole number increase represents a tenfold increase in the amplitude of seismic waves and about 31 times more energy released. For example:
- An earthquake measuring 4.0 on the Richter scale has ten times the amplitude of a 3.0 earthquake.
- It also releases about 31 times more energy than a 3.0.
The scale does not measure the damage caused, which depends on many other factors such as population density and building construction. Magnitude ranges on the scale typically have the following effects:
- Less than 3.5: Generally not felt.
- 3.5 to 5.4: Often felt, but rarely causes damage.
- 6.0 or higher: Usually causes damage to buildings.
- 7.0 or higher: Major earthquake with serious damage.
- 8.0 or higher: Great earthquake with significant damage and loss of life.
The Richter scale has largely been replaced by more accurate scales today, such as the Moment Magnitude scale, but it remains a well-known reference for earthquake magnitude measurement. This scale was developed in 1935 by Charles F. Richter based on seismic wave measurements from seismographs.
