Evolution of instrumentation and techniques in applied geophysics

Over the last hundred years geophysical exploration has become an established, powerful tool in the search for oil and minerals. An historical outline of the development of the instrumentation and the techniques of the four most important geophysical methods (gravity, magnetic, seismic and electrical) up to 1980 is given, starting from the earliest experiments in the 19th century and in the first decade of the 20th century. Particular attention is given to the first successful surveys; these have laid the foundations for a rapid growth. The development of instruments, from the torsion balance to gravity meters, from the Schmidt balance to atomic magnetometers, from mechanical seismographs to digital seismic apparatus is presented schematically, together with statements concerning the theoretical principles of the methods and the development of field data processing and interpretation.