Seismicity is a measure encompassing

earthquake An earthquakealso called a quake, tremor, or tembloris the shaking of the Earth's surface resulting from a sudden release of energy in the lithosphere that creates seismic waves. Earthquakes can range in intensity, from those so weak they ...

occurrences, mechanisms, and

magnitude Magnitude may refer to: Mathematics *Euclidean vector, a quantity defined by both its magnitude and its direction *Magnitude (mathematics), the relative size of an object *Norm (mathematics), a term for the size or length of a vector *Order of ...

at a given

geographical Geography (from Ancient Greek ; combining 'Earth' and 'write', literally 'Earth writing') is the study of the lands, features, inhabitants, and phenomena of Earth. Geography is an all-encompassing discipline that seeks an understanding o ...

location. As such, it summarizes a region's seismic activity. The term was coined by

Beno Gutenberg Beno Gutenberg (; June 4, 1889 – January 25, 1960) was a German-American seismologist who made several important contributions to the science. He was a colleague and mentor of Charles Francis Richter at the California Institute of Technolo ...

and

Charles Francis Richter Charles Francis Richter (; April 26, 1900September 30, 1985) was an American seismologist and physicist. He is the namesake and one of the creators of the Richter scale, which, until the development of the moment magnitude scale in 1979, was w ...

in 1941. Seismicity is studied by

geophysicists Geophysics () is a subject of natural science concerned with the physical processes and properties of Earth and its surrounding space environment, and the use of quantitative methods for their analysis. Geophysicists conduct investigations acros ...

Calculation of seismicity

Seismicity is quantitatively computed. Generally, the region under study is divided in equally sized areas defined by

latitude In geography, latitude is a geographic coordinate system, geographic coordinate that specifies the north-south position of a point on the surface of the Earth or another celestial body. Latitude is given as an angle that ranges from −90° at t ...

and

longitude Longitude (, ) is a geographic coordinate that specifies the east- west position of a point on the surface of the Earth, or another celestial body. It is an angular measurement, usually expressed in degrees and denoted by the Greek lett ...

, and the

Earth's interior The internal structure of Earth are the layers of the Earth, excluding its atmosphere and hydrosphere. The structure consists of an outer silicate solid crust, a highly viscous asthenosphere, and solid mantle, a liquid outer core whose flow ge ...

is divided into various depth intervals on account of Earth's

layering Layering can refer to: * Layering (horticulture), a means of vegetative propagation * Layering (finance), a strategy in high frequency trading * Layering (linguistics), a principle by which grammaticalisation can be detected * Surface layering ...

: Up to depth, , and > . The usual formula to calculate seismicity is:

S = \frac

where :

_i

: is the energy of a single seismic event (i.e., earthquake); :

_0

: interval of

; :

_0

: interval of

_0

: interval of the

hypocenter A hypocenter or hypocentre (), also called ground zero or surface zero, is the point on the Earth's surface directly below a nuclear explosion, meteor air burst, or other mid-air explosion. In seismology, the hypocenter of an earthquake is its ...

; :

_0

: interval of the time of the seismic event. : The result is seismicity as energy per cubic unit.

References

Seismology measurement 1940s neologisms {{Seismology-stub

Calculation of seismicity

See also

References