Exploration geophysics is a profession whose sole activity is to explore the solid earth by physical means. The aim or purpose of exploration geophysical activity is to obtain information about the earth which may be economically or scientifically useful.
During the first few decades of the application of geophysics, constraints on geophysical professional activity were of a type we can call “natural”; that is, our profession was limited in its accomplishments by our own level of knowledge, by the general level of associated sciences and technologies, and by the cost and perceived value of the information we produced. All of these natural constraints have the common property that they can be modified by improvements within our profession. Each time we tried something new we observed the results and adopted those new ideas and techniques which produced beneficial effects. Variations which resulted in poorer results or results not worth the extra cost were dropped from the repertoire.