GEOPHYSICS, the science of earth physics, derived from the Greek 7) (earth) and rl cobots (nature). In the broadest sense geophysics deals not only with the physical properties and forces of the solid earth (lithosphere) but also with those of its liquid (hydrosphere) and gaseous envelopes (atmosphere). It includes, therefore, the following sciences : Higher geodesy; in particular its phases dealing with the shape of the earth, isostasy, and gravity ; seismology ; terrestrial magnetism and electricity ; volcanism ; oceanography and hydrology ; meteorology, clima tology, and atmospheric electricity. The study of the following phenomena is also generally included : Movements of the earth in space ; bodily tides ; precession, nutation, and pole migra tions ; composition of the earth's interior ; cosmogony ; oro genic and epeirogenic movements; acoustic, optical, and elec trical phenomena (aurora borealis, cosmic rays, etc.) in the atmosphere.
Most major nations of the world have provided institutions and observatories to conduct geophysical researches of great variety. In many instances, such institutions are affiliated with Govern ment divisions and appear under various names, such as Geodetic, Geographic, Hydrographic, Oceanographic, Meteorologic, etc. in stitutes or as Magnetic, Seismological, Geophysical, Meteorologi cal or Oceanographic, etc. observatories. Some geophysical in stitutions have been established by private research foundations. In the United States, geophysical research and routine observa tions are carried out largely by the Coast and Geodetic Survey (gravity, magnetic, and seismological surveys; magnetic and seismic observatories), by the Carnegie Institution of Washing ton, D.C. (Department of Research in Terrestrial Magnetism, with several affiliated magnetic observatories in various parts of the world), and the Geophysical Laboratory in Washington, D.C.
In order to promote co-ordination of the efforts of the world's nations in the field of geophysical research, the International Geodetic and Geophysical Union was organized after the World War. In the United States, the American Geophysical Union was established in 1919 as the American Committee of the Inter national Union of Geodesy and Geophysics ; its executive com mittee is the Committee on Geophysics of the National Research Council. It is divided into 7 sections, namely geodesy, seismology, meteorology, terrestrial magnetism and electricity, oceanography, volcanology, and hydrology. Geophysical papers are published in a variety of media. Many geophysical institutions issue their own publications, research papers, activity reports, and compilations of observations. The International Geodetic and Geophysical Union publishes the reports and papers of its sections in various volumes; the Transactions of the American Geophysical Union are issued annually. Articles on geophysical subjects are found in a variety of periodicals such as Terrestrial Magnetism and At mospheric Electricity, Quarterly Journal of the Royal Meteoro logical Society, Meteorologische Zeitschrift, Gerland's Beitraege zur Geophysik, Zeitschrift der Deutschen Geophysikalischen Ge sellschaft, Philosophical Transactions of the Royal Society, etc. References to books dealing with various fields of geophysics, etc. will be found in the articles previously referred to. Books cover ing the entire field of geophysics in English language are scarce. Under the auspices of the National Research Council (U.S.), a series of treatises entitled "Physics of the Earth" is now being published. In Germany, a comprehensive treatment of the subject has been published by Gutenberg and others under the title Hand buch der Geophysik and another has appeared in the Handbuch der Experimentalphysik, Part 25, in three volumes. (C. A. H.)