An earthquake’s magnitude is a measure of the damage the earthquake causes size of seismic waves it produces number of surface waves it produces amount of shaking it produces

The earthquakes magnitude is measured by the size of seismic waves it produces.  Seismic waves are the vibrations from earthquakes that travel through the Earth; they are recorded on instruments called seismographs.  It is greatly measured just because these ground motions by the zigzag movement, can detect strong earthquakes from sources anywhere in the world. 

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