|Very Minor||2 - 2.9||1,300,000 (estimated)|
|Minor||3 - 3.9||130,000 (estimated)|
|Light||4 - 4.9||13,000 (estimated)|
|Moderate||5 - 5.9||1319a|
|Strong||6 - 6.9||134a|
|Major||7 - 7.9||17a|
|Great||8 and higher||1b|
Seismologists use models based on a combination of elastic rebound theory and plate tectonics to try to predict when earthquakes are likely to happen.
These models all link the build-up of stress along a fault with when an earthquake will happen and how large it will be.
In broad terms, for some earthquake zones it is possible to see a pattern, which allows us to predict either when an earthquake is likely to happen or how big it is likely to be, but it is not possible to predict likely timing and size.
What we can say, however, is that minor earthquakes occur frequently, while major earthquakes are relatively rare.
Demonstrate how difficult it can be to predict when sudden Earth events will be triggered. For example, a volcanic eruption, a landslide or rupture leading to an earthquake.