Example of cross-sections representing the distribution of magnetization in the Earth’s Crust. (a) Magnetization with a two-dimensional structure. (b) Magnetization with a one-dimensional structure. The x1 axis is the direction in which the magnetic anomaly extends; the x3 axis is vertically downward; the x2 axis is chosen in such a way that x1x2x3 forms a right-hand orthogonal system. The thick black lines represent the upper and the lower boundaries of the Earth’s crust. Gray areas represent the magnetized crust.