Analysis and Interpretation of Geomagnetic Anomalies

Abstract

The analysis and interpretation of geomagnetic anomalies is discussed. Techniques are described for estimating depth and strength of magnetized ore‐bodies, using tables and graphs of the fields of simple models. Relations among surface‐components of field of anomalies are derived, using fitting or representation of anomalies by Fourier series, Fourier‐Bessel series, and power series. A method based on the analysis of surface magnetic fields by integrals is also described. Methods are given for estimating probable minimum and maximum depths to magnetic sources beneath the Earth's surface, using measurements of field at the surface. The locations of sources cannot be uniquely inferred from magnetic data alone. The use of gradients of field in locating sources of anomaly is indicated.