Charles Francis Richter of magnitude 7 would be ten times stronger than a 6, a hundred times stronger than a 5, and a thousand times stronger than a 4. (The 1989 Loma Prieta earthquake that shook San Francisco was magnitude 6.9.) The Richter scale was published in 1935 and immediately became the standard measure of earthquake intensity. Richter did not seem concerned that Gutenberg's name was not included at first; but in later years, after Gutenberg was already dead, Richter began to insist for his colleague to be recognized for expanding the scale to apply to earthquakes all over the globe, not just
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