| Descriptor | Magnitude | Frequency |
| Great | 8+ | 1 in 25 years |
| Major | 7 - 7.9 | 1 in 16 years |
| Strong | 6 - 6.9 | 1 in 4 years |
| Moderate | 5 - 5.9 | 35 every year |
| Light | 4 - 4.9 | 1550 every year (estimated) |
| Minor/Micro | 3 - 3.9 | 5500 every year (estimated) |
| Very Minor/Very Micro | 2 - 2.9 | 100,000 every year (estimated) |