Summary

Unlike the 2D case, the total gradient (magnitude of the gradient vector) in 3D is not the envelope of either the vertical or horizontal derivatives of the total-field anomaly over all possible directions of the earth''s field and source magnetization. Instead, the total gradient of the reduced-to-pole data defines the envelope for the vertical derivative while the total gradient of the reduced-to-equator data defines the envelope for the horizontal derivative.

Introduction

Nabighian (1972) showed that the horizontal and vertical derivatives of the magnetic anomaly produced by a 2D source form a Hilbert transform pair and define an analytic signal.

This content is only available via PDF.
You can access this article if you purchase or spend a download.