Seismicity is a measure encompassing
earthquake
An earthquake (also known as a quake, tremor or temblor) is the shaking of the surface of the Earth resulting from a sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can range in intensity, from ...
occurrences, mechanisms, and
magnitude at a given
geographical
Geography (from Greek: , ''geographia''. Combination of Greek words ‘Geo’ (The Earth) and ‘Graphien’ (to describe), literally "earth description") is a field of science devoted to the study of the lands, features, inhabitants, and ...
location. As such, it summarizes a region's seismic activity. The term was coined by
Beno Gutenberg and
Charles Francis Richter
Charles Francis Richter (; April 26, 1900 – September 30, 1985) was an American seismologist and physicist.
Richter is most famous as the creator of the Richter magnitude scale, which, until the development of the moment magnitude scale in 19 ...
in 1941. Seismicity is studied by
geophysicists
Geophysics () is a subject of natural science concerned with the physical processes and physical properties of the Earth and its surrounding space environment, and the use of quantitative methods for their analysis. The term ''geophysics'' so ...
.
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 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 the south pole to 90° at the north po ...
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 let ...
, and the
Earth's interior is divided into various depth intervals on account of
Earth's layering: Up to depth, , and > .
The usual formula to calculate seismicity is:
where
:
: is the energy of a single seismic event (i.e., earthquake);
:
: interval of
latitude
In geography, latitude is a 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 the south pole to 90° at the north po ...
;
:
: interval of
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 let ...
:
: interval of the
hypocenter;
:
: interval of the time of the seismic event.
: The result is seismicity as energy per cubic unit.
See also
*
Moment magnitude scale
The moment magnitude scale (MMS; denoted explicitly with or Mw, and generally implied with use of a single M for magnitude) is a measure of an earthquake's magnitude ("size" or strength) based on its seismic moment. It was defined in a 1979 pap ...
*
Plate tectonics
Plate tectonics (from the la, label= Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is the generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of large t ...
*
Seismology
Seismology (; from Ancient Greek σεισμός (''seismós'') meaning "earthquake" and -λογία (''-logía'') meaning "study of") is the scientific study of earthquakes and the propagation of elastic waves through the Earth or through other ...
*
Wadati–Benioff zone
References
Seismology measurement
1940s neologisms
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