Geophysics
The study of the structure and dynamic behavior of the earth and other planets using the methods of physics. Geophysicists are experts on tectonics, seismology, the generation of a planetary magnetic field, and the study of mass distributions. They are knowledgeable about methods for mapping the internal planetary structure and past history, including gravimetrics, measuring seismic transmission, changes to the magnetic field, and the history of the magnetic field as recorded in rocks. They are familiar with the properties of rock within a planet, including strength, elasticity, rigidity, crystal structure, radioactivity, and thermal properties.