The magnitude of most earthquakes is measured on the Richter scale, invented by Charles F. Richter in 1934.

The Richter magnitude is calculated from the largest seismic wave - a wave that travels through the earth as a result of a tectonic earthquake.

For each whole number you go up on the Richter scale, the amplitude of the ground motion recorded by a seismograph goes up ten times.

So, for example, an earthquake with a magnitude of 5 would result in ten times the level of ground shaking as a magnitude 4 earthquake.

Magnitude three or lower earthquakes are mostly imperceptible, while at the other end of the scale a magnitude seven quake causes serious damage over large areas.

According to the scale, a 5.2 magnitude quake would result in everyone noticing.

It suggests dishes may break and open doors would swing.