Surface wave magnitude Surface wave magnitude The surface wave magnitude (formula_1) scale is one of the magnitude scales used in seismology to describe the size of an earthquake. It is based on measurements in Rayleigh surface waves that travel primarily along the uppermost layers of the Earth. It is currently used in People's Republic of China as a national standard(GB 17740-1999) for categorising earthquakes. Surface wave magnitude was initially developed in the 1950s by the same researchers who developed the local magnitude scale M in order to improve resolution on larger earthquakes: Recorded magnitudes of earthquakes during that time, commonly attributed to Richter,
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