Earth model
In the geosciences, an earth model is a mathematical representation of the earth's figure or a mathematical-physical model of the earth's interior . By examining deviations of the model properties from the actual earth body , the earth figure and the earth's interior can be investigated more and more precisely.
Properties and phenomena used for this analysis include:
- Geometric parameters such as the size and shape of the earth's ellipsoid , direction and speed of the earth's rotation , changes in the earth's rotation, pole movement , precession and nutation
- Physical fields ( gravitational field , magnetic field , electrical potentials ), vibrations and geoseismics
- physical parameters of the layer structure ( earth's crust , earth's mantle and intervening discontinuities ), mean density and elasticity modules of the individual layers, rock type, pressure , temperature, heat flow , etc.
In geodesy , appropriately selected earth models reduced to as few parameters as possible are also used as reference systems for coordinates on the earth's surface, as well as for short-term geodynamic processes and long-lasting movements (e.g. continental drift as a result of plate tectonics).
In gravimetry and seismology , models of the deeper layers of the earth are used to determine anomalies in their storage, density, elasticity or composition. The Applied Geophysics , by interpretation of gravity anomalies or seismic reflections on subterranean deposits close, while the Theoretical Geophysics and Geodesy (Astronomical and Physical Geodesy) by comparison of model and observations to the large-scale structure of the earth and its behavior as a planet can explore.
As a simple model of the globe can also be a globe are considered. In addition to the earth's surface, some globes also show the changing position in relation to the plane of the earth's orbit or the position of the sun in the changing seasons.
See also
- Geodetic earth model , GRS80 , WGS84 , ITRF
- Geophysical earth model NUVEL
- Theoretical gravity formula
- Geoid
literature
- Klaus-Peter Schwarz (Ed.): Geodesy beyond 2000 - the challenges of the first decade . General Assembly Birmingham 1999, 437 p., International Association of Geodesy, 2000
- Wolfgang Torge : Geodesy . In particular, chap. 4, The Geodetic Earth Model and Chap. 8, Structure and Dynamics of the Earth . Verlag de Gruyter, Berlin 2001.