Mercalli intensity scale Mercalli intensity scale The Mercalli intensity scale is a seismic intensity scale used for measuring the intensity of an earthquake. It measures the "effects" of an earthquake. It is distinct from the moment magnitude ("M") usually reported for an earthquake, which is a measure of the "energy" released (sometimes misreported as the Richter magnitude, "M"). The intensity of an earthquake is not entirely determined by its magnitude. It is not based on first physical principles, but is, instead, empirically based on observed effects. The Mercalli scale quantifies the effects of an earthquake on the Earth's surface, humans, objects of nature,
Absolute magnitude and a difference of n magnitudes in absolute magnitude corresponds to a luminosity ratio of 100. For example, a star of absolute magnitude M=3 would be 100 times more luminous than a star of absolute magnitude M=8 as measured in the V filter band. The Sun has absolute magnitude M=+4.83. Highly luminous objects can have negative absolute magnitudes: for example, the Milky Way galaxy has an absolute B magnitude of about −20.8. An object's absolute bolometric magnitude represents its total luminosity over all wavelengths, rather than in a single filter band, as expressed on a logarithmic magnitude scale. To convert