ESTIMATION OF THE DIRECTION OF MAGNETIZATION OF A BODY CAUSING A MAGNETIC ANOMALY USING A PSEUDO‐GRAVITY TRANSFORMATION

Abstract

A two‐dimensional form of the pseudo‐gravity transformation, applicable to bodies magnetized in directions not parallel to the ambient field, is given. Assuming that a body of finite cross section is magnetized in the same direction and sense at every point, then an adaptation of this pseudo‐gravity transformation enables the direction of magnetization of the body to be estimated, within limits, from the magnetic anomaly it causes. The method has been programmed for a computer. A simple extension enables it to be applied to three‐dimensional bodies. The method is shown to be reliable by testing it against calculated magnetic profiles over geometrical shapes. It is applied to the Lambay magnetic anomaly in the west Irish Sea, showing this to be caused by a body magnetized approximately in the direction of the present earth’s field.