New insights into magnetic derivatives for structural mapping

Abstract

Magnetic and gravity derivatives can be likened to seismic attributes in that they can help define/estimate the physical properties of the source structure causing the anomaly. This contribution looks at the tilt derivative, first reported in 1994 and more recently used to derive the local wavenumber (1997). We will show that the combination of the tilt derivative and its total horizontal derivative are highly suitable for mapping shallow basement structure and mineral exploration targets and that they have distinct advantages over many conventional derivatives. We provide the simple theory behind the derivatives, use a range of simple 2D models to illustrate their response, and apply them to mapping a mineral target in Namibia.