Our workSeismic methods used to study the internal structure of Earth as a whole and its structure at different depths. It should be noted that, based on seismic studies found that the Earth is composed of the nucleus, the Earth's mantle and crust. The use of digital seismographs played an enormous role in studying the earth's bowels and allowed to record the earthquake. According to the wave of changes speeds scheme was drawn up three-dimensional structure of the mantle. The structure of the upper mantle, defined in the velocities of seismic waves, different areas for mid-ocean ridges and continents and is consistent with the distribution of heat flow. A similar picture of changes in velocity waves noted in the lower mantle, but they do not correlate with makrorelefom the Earth's surface. See also EARTHQUAKE.
Geodesy investigates mainly form the Earth. There are two geodesic task: defining parameters spheroid or ellipsoid (which provides the best convergence with the surface of the sea), a first approximation approximating the Earth's shape, and measurement of the actual deviations from the surface geoid spheroid. In essence, form the Earth's rotation is a ellipsoid, splyuschenny slightly at the poles. Some form of geoid and spheroid carried out mainly through a combination of ground-based geodetic surveying and studying the orbits of satellites. The changes form the Earth, associated with the movement litosfernyh plates are determined according to the radiointerferometrii and global positioning systems (G R S). See also GEODEZIYA.
Gravimetry has been studying the Earth's gravitational field. Local variation of this field is related to the density irregularities in the Earth's crust are used to determine the ore bodies. Is believed that the earth's surface topography and density changes within the Earth's crust deep mutually compensated, so satisfactory correlation between the length of gravitational anomalies 100-1000 km and there is no relief.