The Richter / magnitude scale measures earthquake size. It is logarithmic — each whole number is about 32× more energy than the one below.
| Magnitude | Class | Effects |
|---|---|---|
| Less than 2.0 | Micro | Not felt |
| 2.0 – 3.9 | Minor | Often felt, rarely causes damage |
| 4.0 – 4.9 | Light | Noticeable shaking, minor damage |
| 5.0 – 5.9 | Moderate | Damage to weak buildings |
| 6.0 – 6.9 | Strong | Damage in populated areas |
| 7.0 – 7.9 | Major | Serious damage over large areas |
| 8.0 and up | Great | Severe, total destruction near epicentre |