Why can't the ritcher scale be used worldwide (universally)?

Question

Why can't the ritcher scale be used worldwide (universally)?

Answer 1

I presume you mean the Richter scale for the relative strength of earthquakes.  As it can apply for any earthquake, it can be used worldwide.

Answer 2

Because of the variation in the distance between the various seismographs and the epicenter of the earthquakes. Richter used the data from seismographs in Southern California.   Adjustments are included in the magnitude formula to compensate for this variation.  Using the adjustments makes the Richter Scale usable world wide.

Answer 3

if his scale were as long as my Woody, It would work world wide.