Historically geophysics has been the study of the classical linear equations of physics, Laplace's equation for gravity and magnetics, the wave equation for propagating seismic waves, and the heat equation for thermal problems.
Christopher C. Barton; Paul R. La Pointe (28 February 1995). Fractals in the Earth Sciences. Springer Science & Business Media. p. 2. ISBN 978-0-306-44865-2.