Magnitude scales can be used to describe earthquakes so small that they are expressed in negative numbers. The scale also has no upper limit. Learn more about how we measure earthquake magnitude.
| Magnitude | Earthquake Effects | Estimated Number Each Year |
|---|---|---|
| 2.5 or less | Usually not felt, but can be recorded by seismograph. | Millions |
| 2.5 to 5.4 | Often felt, but only causes minor damage. | 500,000 |
| 5.5 to 6.0 | Slight damage to buildings and other structures. | 350 |
| 6.1 to 6.9 | May cause a lot of damage in very populated areas. | 100 |
| 7.0 to 7.9 | Major earthquake. Serious damage. | 10-15 |
| 8.0 or greater | Great earthquake. Can totally destroy communities near the epicenter. | One every year or two |