Rich·ter scale 
/ˈrɪktɚ-/ noun
/ˈrɪktɚ-/ noun Meaning:
the Richter scale
technical : a system of measurement used for showing the strength of an earthquake
▪ The earthquake was a 4.5 on the Richter scale. = The earthquake measured 4.5 on the Richter scale.
▪ The earthquake was a 4.5 on the Richter scale. = The earthquake measured 4.5 on the Richter scale.
