Richter magnitude scale Richter magnitude scale The so-called Richter magnitude scale – more accurately, "Richter's magnitude scale", or just "Richter magnitude" – for measuring the strength ("size") of earthquakes refers to the original "magnitude scale" developed by Charles F. Richter and presented in his landmark 1935 paper, and later revised and renamed the Local magnitude scale, denoted as "ML" or "M". Because of various shortcomings of the ML scale most seismological authorities now use other scales, such as the moment magnitude scale (), to report earthquake magnitudes, but much of the news media still refers to these as "Richter" magnitudes. All magnitude scales
Order of magnitude Order of magnitude An order of magnitude is an approximate measure of the number of digits that a number has in the commonly-used base-ten number system. It is equal to the logarithm (base 10) rounded to a whole number. For example, the order of magnitude of 1500 is 3, because 1500 = 1.5 × 10. Differences in order of magnitude can be measured on a base-10 logarithmic scale in “decades” (i.e., factors of ten). Examples of numbers of different magnitudes can be found at Orders of magnitude (numbers). Generally, the order of magnitude of a number is the smallest power