Japan Meteorological Agency seismic intensity scale Japan Meteorological Agency seismic intensity scale The Japan Meteorological Agency seismic intensity scale is a seismic scale used in Japan to measure the intensity of earthquakes. It is measured in units of . Unlike magnitude measures such as the moment magnitude scale (Mw), and the earlier Richter magnitude scale, which attempt to describe the energy released by the earthquake, the JMA scale describes the degree of shaking at various points on the Earth's surface, and is analogous to the Mercalli intensity scale. The intensity of an earthquake is not totally determined by its magnitude, but varies with event's depth, and
Absolute magnitude using an absolute magnitude, one must specify the type of electromagnetic radiation being measured. When referring to total energy output, the proper term is bolometric magnitude. The bolometric magnitude usually is computed from the visual magnitude plus a bolometric correction, . This correction is needed because very hot stars radiate mostly ultraviolet radiation, whereas very cool stars radiate mostly infrared radiation (see Planck's law). Some stars visible to the naked eye have such a low absolute magnitude that they would appear bright enough to outshine the planets and cast shadows if they were at 10 parsecs from the Earth. Examples