Regional mapping of the lunar magnetic anomalies at the surface: Method and its application to strong and weak magnetic anomaly regions

Abstract

We have developed a new method for regional mapping of the lunar magnetic anomalies as the vector field at the surface using the satellite observation, that is the surface vector mapping (SVM). The SVM is based on the inverse boundary value problem with a spherical boundary surface. There are two main procedures for reducing effects of bias and noise on mapping: (1) preprocessing the data to provide first derivatives along the pass, and (2) the Bayesian statistical procedure in the inversion using Akaike’s Bayesian Information Criterion. The SVM was applied to two regions: the northwest region of the South Pole-Aitken basin as a strong magnetic anomaly region, and the southeast region of the lunar near side as a weak magnetic anomaly region. Since the results from the different datasets of the Kaguya and Lunar Prospector observations show good consistency, characteristic features of the lunar magnetic anomalies at the surface are considered to be well estimated except for components of wavelength shorter than about 1°. From the results by the SVM, both of the regions show elongation patterns of the lunar magnetic anomalies, suggesting lineated structures of the magnetic anomaly sources.