Modal decomposition of magnetic maps: the case of Cape Roberts aeromagnetic survey, Antarctica

Abstract

This paper proposes a digital enhancement tool for magnetic anomaly maps. The magnetic anomaly map is decomposed by means of Eigenvalue Decomposition into a number of orthogonal bases. The dataset is then filtered accordingly to a specific variance pattern. The dataset is decomposed and the eigenvalues population is inspected so that the variance is evaluated yielding the definition of two thresholds. Subsequently, the dataset is reconstructed into three subsets which hold different features respectively. The proposed filtering procedure is first tested with a synthetic signal and then applied to the data of Cape Roberts (Antarctica) aeromagnetic survey, flown over an off-shore rift basin. The proposed method appears to be efficient in noise removal and acts as a digital enhancement tool which provides TMI anomaly maps revealing hidden lineaments, otherwise not visible. The methodology effectiveness as a hidden lineaments detection tool has been checked against independent data.