Geophysics, a major discipline of Earth sciences, is the study of the Earth by quantitative physical methods, especially by seismic, electromagnetic, and radioactivity methods. History of geophysics has been motivated by theoretical and practical isues. The term of geophysics was probably first used in Germany, where it appeared in scientific writings of the mid-19th century. The word geophysics was first used by Fröbel as "geophysik" in 1834. The theories and techniques of geophysics are… (More on Geophysical)