How do scientists measure the size of earthquakes?

This earthquake has been measured as an 8.8 according to the US Geological Survey – which they say makes it the sixth largest recorded in history.

The scale that geologists use to measure earthquakes is called the Moment Magnitude scale.

It looks at various physical features like how much ground was moved, by how far, and how strong is the rock material being moved.

This is all worked out by analysing the waves produced from the ground shaking.

The scale is logarithmic which means that each increase in number is equivalent to a ten-fold increase in size. So an earthquake measuring 8 on the scale is 10 times bigger than one measured at 7.