UC San Diego

SUMMARY Autonomous underwater vehicles (AUVs) provide high-resolution magnetic measurements essential for investigating crustal accretion, tectonic segmentation and hydrothermal processes at mid-ocean ridges. However, raw magnetometer measurements are strongly influenced by platform-induced magnetic fields, attitude-dependent biases and navigation uncertainties that must be corrected to recover geophysically meaningful anomaly fields. We apply a procedure to measurements from AUVs, which includes platform independent scalar calibration, transformation into geographic reference frames, spin-based removal of permanent and induced vehicle magnetization and computation of magnetic anomalies relative to the International Geomagnetic Reference Field. The framework also incorporates a 2-D spectral upward continuation to reconcile altitude variations, thereby recovering anomalies at a uniform reference level. Application of this system to AUV data sets from the East Pacific Rise and Mid-Atlantic Ridge demonstrates effective suppression of platform biases, improved crossover consistency and the generation of internally coherent geomagnetic anomaly fields suitable for subsequent analysis and mapping.