Richter magnitude scale (formula_20) in the energy released. The elastic energy radiated is best derived from an integration of the radiated spectrum, but an estimate can be based on formula_4 because most energy is carried by the high frequency waves. The Richter magnitude of an earthquake is determined from the logarithm of the amplitude of waves recorded by seismographs (adjustments are included to compensate for the variation in the distance between the various seismographs and the epicenter of the earthquake). The original formula is: where A is the maximum excursion of the Wood-Anderson seismograph, the empirical function A depends only on the epicentral
Apparent magnitude further qualification, it is usually the V magnitude that is meant, more or less the same as visual magnitude. Because cooler stars, such as red giants and red dwarfs, emit little energy in the blue and UV regions of the spectrum their power is often under-represented by the UBV scale. Indeed, some L and T class stars have an estimated magnitude of well over 100, because they emit extremely little visible light, but are strongest in infrared. Measures of magnitude need cautious treatment and it is extremely important to measure like with like. On early 20th century and older orthochromatic