Potential Field Methods
Gravitational and magnetic fields obey Laplace’s equation, so, by definition, both gravity and magnetic fields are types of potential fields. Thus, the gravity and magnetic geophysical methods can be classified as potential field methods. Furthermore, the gravity and magnetic methods are passive geophysical methods, as they measure naturally occurring potential fields without having to apply any potential field, energy, or force. Ground surface gravity methods measure variations in the density of the earth, whereas magnetic methods detect the alteration of earth’s magnetic field. Further explanations of both methods are linked below.