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The use of Fourier’s transformation and the representation of magnetic anomalies in the form of frequencies (power-spectra) have enabled a thorough analysis of the magnetic anomalies and the estimation of depths at which their source exit. The method applied computes the spectrum of anomalies in the potential (magnetic) field from the data of a profile arid of a two-dimensional map. The average interpreted depths from the power spectrum are assigned to the centre of the profile and to die center of the map.

As an example, the interpretation of the total aeromagnetic survey of Gabal (G.) El Erediya area, Eastern Desert, Egypt was tried. The two average depths estimated for the near-surface and deep-seated interfaces using the profiles in both the N-S and E-W directions are 0.55 and 1.60 km, while those estimated using the two-dimensional map are 0.59 and 1.31 km respectively. It was found that the area under study consists of a series of simple and complex alternating NW-SE and ENE-WSW trending horsts (or uplifted blocks) and grabens (or downfaulted blocks). The previous trend parallels the Red Sea and some segments of the River Nile, while die latter trend parallels the shear zone of Safaga-Qena. The shorter wavelength (ENE) seems to suffer rejuvenation, i.e., more than one tectonic event and is consequently more ancient. Meanwhile, the longer wavelength (NW) appears to undergo only one tectonic event and is accordingly more recent.