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,
Logarithmic scale the value of a logarithm function. Here, a given logarithmic unit will be denoted using the notation [log "n"], where "n" is a positive real number, and [log ] here denotes the indefinite logarithm function Log(). Examples of logarithmic units include common units of information and entropy, such as the "bit" [log 2] and the "byte" 8[log 2] = [log 256], also the "nat" [log e] and the "ban" [log 10]; units of relative signal strength magnitude such as the "decibel" 0.1[log 10] and "bel" [log 10], "neper" [log e], and other logarithmic-scale units such as the Richter magnitude scale