Backus and Gilbert inversion of 2.5-d gravity and magnetic anomalies with application to Curie isothermal depth determination


An inversion method that solves for a parameter as a continuous function (Backus-Gilbert) is used to determine the lower boundary of a two and one-half dimensional body which causes either a gravity or a magnetic anomaly and then assesses the vertical accuracy (variance) and the lateral resolution (spread). Also the gravity and magnetic data are simultaneously inverted and this procedure improves the resolution of the model over that obtained by inverting either data set individually. The usefulness of the Backus-Gilbert approach is evaluated by a study of the inversion of both synthetic gravity and magnetic data. The convergence characteristics, the amount and distribution of the data and the role of incorrect or correct parameters are considered. The magnetic inversion algorithm is used to determine the depth of the Curie isotherm in western Arizona. The results indicate that the transition zone has shallower Curie isotherm depths than the Colorado Plateau and the Basin aand Range province.

Document Type

Conference Proceeding



Publication Date


Journal Title

1989 SEG Annual Meeting