Measurements of the geomagnetic field can be used to help determine the structure of the Earth, since rocks often contain magnetic minerals. Measurements of the strength of the Earth's gravitational field can also be used, since the more dense the rocks, the stronger the field. The interpretation of large amounts of data can be aided by "automatic" interpretation techniques such as Euler deconvolution. This considers the anomalies to be caused by many relatively simple sources (such as dipoles or lines of dipoles) and produces the positions and depths of these sources. This data can then be used as a basis for a more detailed interpretation.
Reference:
Durrheim, RJ and Cooper GRJ. 1998. Euldep: A program for the Euler deconvolution of magnetic and gravity data. Computers and Geosciences, vol 24 (6), pp 545-550
Durrheim, R., & Cooper, G. (1998). Euldep: A program for the Euler deconvolution of magnetic and gravity data. http://hdl.handle.net/10204/1409
Durrheim, RJ, and GRJ Cooper "Euldep: A program for the Euler deconvolution of magnetic and gravity data." (1998) http://hdl.handle.net/10204/1409
Durrheim R, Cooper G. Euldep: A program for the Euler deconvolution of magnetic and gravity data. 1998; http://hdl.handle.net/10204/1409.