Seismic magnitude scales E, in Joules), difficulty in implementing it using the technology of the time led to revisions in 1958 and 1960. Adaptation to local conditions has led to various regional K scales, such as K and K. K values are logarithmic, similar to Richter-style magnitudes, but have a different scaling and zero point. K values in the range of 12 to 15 correspond approximately to M 4.5 to 6. M(K), M, or possibly M indicates a magnitude M calculated from an energy class K. Earthquakes that generate tsunamis generally rupture relatively slowly, delivering more energy at longer periods (lower frequencies) than
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