Three-Dimensional Inversion of Magnetic Anomalies Using a Low-Level Representation and an Evolution Strategy for Archaeological Studies

Geophysical data inversion typically involves the numerical solution of high-dimensional ill-posed problems. To reduce the non-uniqueness, prior information in the form of appropriate regularization schemes, together with a proper representation of the quantities of interest, is helpful. To this end, methods are recommended that take into account a low-dimensional formulation of the inverse problem, a suitable representation for the quantities of interest, and a helpful numerical procedure. Structural aspects of the objects of interest, such as the dimensions of structures, are often available as prior knowledge in archaeological magnetic surveys. However, they are not easily exploited by classical geophysical data inversion applications; for example, a typical representation together with Tikhonov-like regularization schemes or total variation, which promote smoothness in the solutions, occlude underlying structural information or retrieve fuzzy boundaries. In this work, a three-dimensional inversion of magnetic data is developed based on an evolution strategy. It is adapted to a numerical representation that easily incorporates aspects achievable at archaeological sites. Synthetic test cases and a magnetic dataset corresponding to an archaeological site are used to report the results.