Gutenberg–Richter law Gutenberg–Richter law In seismology, the Gutenberg–Richter law (GR law) expresses the relationship between the magnitude and total number of earthquakes in any given region and time period of "at least" that magnitude. or Where: The relationship between earthquake magnitude and frequency was first proposed by Charles Francis Richter and Beno Gutenberg in a paper published in 1956. This relationship between event magnitude and frequency of occurrence is remarkably common, although the values of a and b may vary significantly from region to region or over time. The parameter b (commonly referred to as the "b-value") is commonly close to 1.0
Absolute magnitude corresponds to absolute bolometric magnitude 4.74. Placing a radiation source (e.g. star) at the standard distance of 10 parsecs, it follows that the zero point of the apparent bolometric magnitude scale corresponds to irradiance . Using the IAU 2015 scale, the nominal total solar irradiance ("solar constant") measured at 1 astronomical unit () corresponds to an apparent bolometric magnitude of the Sun of −26.832. Following Resolution B2, the relation between a star's absolute bolometric magnitude and its luminosity is no longer directly tied to the Sun's (variable) luminosity: where The new IAU absolute magnitude scale permanently disconnects the scale from