Are earthquakes on the increase?
NO. There is no evidence that earthquakes are becoming more frequent, we are simply recording larger numbers, especially of small earthquakes. The number of larger events remains stable. As extensive world-wide monitoring networks continue to expand, more events are located each year. The table below details USGS data for the frequency of earthquakes since 1900:
FREQUENCY OF OCCURRENCE OF EARTHQUAKES BASED ON OBSERVATIONS SINCE 1900
| Descriptor | Magnitude | Average Annually |
|---|---|---|
| Great | 8 and higher | 1 |
| Major | 7 - 7.9 | 18 |
| Strong | 6 - 6.9 | 120 |
| Moderate | 5 - 5.9 | 800 |
| Light | 4 - 4.9 | 6,200 (estimated) |
| Minor | 3 - 3.9 | 49,000 (estimated) |
| Very Minor | 2 - 3.0 | about 1,000 per day |
| Very Minor | 1 - 2 | about 8,000 per day |
