Richter magnitude scale magnitude (M) and body wave magnitude (M) scales. The Richter scale was defined in 1935 for particular circumstances and instruments; the particular circumstances refer to it being defined for Southern California and "implicitly incorporates the attenuative properties of Southern California crust and mantle." The particular instrument used would become saturated by strong earthquakes and unable to record high values. The scale was replaced in the 1970s by the moment magnitude scale (MMS, symbol ); for earthquakes adequately measured by the Richter scale, numerical values are approximately the same. Although values measured for earthquakes now are formula_1 (MMS), they are frequently
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