Magnitude規模—a uniform measurement of sizeProportional to log (maximum amplitude (Amax) of seismograph motion) Amax is normalized to a distance (100 km)This is called Richter magnitudeSeveral magnitude scales are used.Richter (ML)芮氏規模—useful near the epicenterMoment (MW)地震矩規模—most accurate measureMagnitude scales are logarithmic.M6.0 is ten times an M5.0.M7.0 is a thousand times an M4.0