Abstract Aeromagnetic data from the Southern Tyrrhenian Sea have been analysed, to remove the contributions of shallow and deep sources to the magnetic anomalies by applying a processing technology that increases the informative potential of the magnetic data acquired by AGIP with great accuracy, uniform distribution and high density. The aeromagnetic anomaly field has been reduced to the bottom topographic surface by the bottom reduction method. Spectral signal analysis has been carried out to separate low- and high-frequency components. The spectral reference field (SRF), obtained from the cotransformation of low frequencies, gives information about deep magnetic structures. The high-frequency components, computed from the difference between the magnetic anomaly field and the SRF, provides the spectral anomaly field (SAF). The bottom reduced magnetic anomaly field is derived by merging the high- and low-frequency bands. The resulting map provides information about geotectonic features in the Southern Tyrrhenian area and shows the effectiveness of the adopted approach over traditional procedures.