Application of the Hilbert transform in resolution of magnetic signals: a new technique

Abstract

Detailed magnetic surveys were conducted in the Chikativaripalle?Gollapalle area of the Cuddapah Basin, AP, India, where the geological mapping was carried out. Since the magnetic anomalies of this area are of very low amplitude, a new filter was generated, using the Hilbert transform, in order to enhance the signal from noisy data. Filter Mj is the summation of the multiplied values of the horizontal derivative of the anomaly and its corresponding Hilbert transform (or vertical gradient), three values each at a time (three point data window), from one end of the profile. The process was repeated by sliding the data window along the entire profile. Each filter coefficient was attributed at the middle point of the data window. The filter Mj was convolved with the first horizontal derivative (M ´ A) and with its Hilbert transform (M ´ H). The resolved magnetic signals were identified with the contacts and faults. Also these were identified with the mineralized zone on the eastern part of the profiles; the central and western part of the profiles were identified along the axes of synclinal and anticlinal structures respectively. It was correlated with borehole data and confirmed the existence of structures and mineralized zones. These studies are immensely helpful for qualitative interpretation of weak magnetic anomalies.