the magnitude of most earth quakes is measured on the Richter scale when we talk about great earth quake it mesures 8 or more; when it is major it mesures 7-7,9 ; when it is strong it mesures 6-6,9 ; when it is moderate it mesures 5-5,9 ; when it is light it mesures 4-4,9 ;when it is minor it mesures 3-3,9