Home pageGEOPHYSICS, complex sciences, physical methods of investigating the structure of the Earth. Geophysics in the broadest sense is studying the physics of solid Earth (Earth's crust, mantle, liquid and solid external internal kernel), the physics of the oceans, land surface water (lakes, rivers, ice) and groundwater, as well as the physics of the atmosphere (meteorology, climatology, Aeronomy) .
This article is considered extremely solid Earth physics, which are the main sections of seismology, geodesy, gravimetry, geomagnetizm, BOTH GEOELECTRICS, Geothermal, rheology, physics of minerals and rocks. Applied Geophysics develops methods and the theory of geophysical surveys and geophysical exploration, mainly with a view to finding mineral deposits (see GEOFIZICHESKAYA EXPLORATION). The marine geophysics conducts research in seas and oceans.
Geophysics uses data from other sciences, mainly physics and geology as well as mathematics, astronomy, crystallography, geochemistry. A large influence on the development of geophysics have the results of space research and development of the theory of tectonic plates. See also LAND.
Seismology studying earthquakes, their mechanisms and consequences, the spread of seismic waves, as well as all types of crustal movements, which are recorded on seismographs land and at the bottom of the oceans and seas. The most active earthquake zones observed in the weakened along the borders of tectonic plates. In doing so, brought three types of seismic waves: longitudinal (P), transverse (S) and surface (Love and Rayleigh waves). Strong earthquake may also initiate free variations across the Earth.
Election seismically safe places for the construction of facilities is projected earthquake engineering seismology. The real methodology for accurate prediction of earthquakes time and place does not exist yet. It is known that the most powerful earthquake accompany the process of subduction (poddviga) in the deep gutters or movement to transform faults. This makes it possible to predict areas of possible earthquakes. Information about the expected jolting force is essential to determine possible effects on seismic intensity of such facilities as nuclear reactors, dams, bridges and buildings.
Seismic 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.