Get ready to rumble – there’s a whole lot of shaking going on because today is Richter Scale Day. April 26 is the birthday of Charles Richter (born in 1900 in Overpeck, Ohio) who developed the eponymous scale for comparing earthquakes. Richter repeated emphasized that there is no upper limit to the scale, however each level of the scale represents a ten-fold increase in magnitude from the previous level. The most powerful earthquake recorded was the 1960 Chilean earthquake that measured 9.5 on the scale.
Magnitude differs from intensity, as explained on the USGS earthquake site:
Magnitude and Intensity measure different characteristics of earthquakes. Magnitude measures the energy released at the source of the earthquake. Magnitude is determined from measurements on seismographs. Intensity measures the strength of shaking produced by the earthquake at a certain location. Intensity is determined from effects on people, human structures, and the natural environment.
For a comparison of magnitude versus intensity, look here.
Gunsmoke and Knitting 