Geophysics is the study of Earth physics. This includes physical phenomena such as gravity, heat flow, seismicity, radioactivity, magnetism, and fluid dynamics. A geophysicist applies the principles of physics to the understanding of geology.
Geophysics can be broken down into two categories: global geophysics and exploration geophysics. Global geophysics is concerned with earthquakes, the magnetic field, physical oceanography, studies of the Earth's thermal state, and meteorology. Exploration geophysics is concerned with the physical principles applied to the search for resources such as oil, gas, minerals, water, and building materials.
Geophysics is a subfield of both earth science and physics. It is related to planetary science, atmospheric sciences, and geological engineering.