Amplitudes of the piezomagnetic signals arising from Rayleigh waves propagating over magnetic anomalies. Panels in the top row show plan views of definitions of the directions employed in the calculation. Definitions of the x1 and x2 axis are provided in Fig. 1. The other panels show the corresponding results. Curves represent the amplitudes of signals arising from non-uniformly magnetized crust (i.e., Fig. 1(a)), and dashed lines represent those arising from uniformly magnetized crust (i.e., Fig. 1(b)). The second, third, and fourth rows from the top show results corresponding to Rayleigh waves propagating to the north, northeast, and east, respectively. The left, center, and right columns show plan views and results corresponding to the cases of magnetic anomalies oriented north-south, northwest-southeast, and east-west, respectively. In each panel, D represents the direction of magnetic north (i.e., X axis), as measured from the direction in which the magnetic anomaly extends (i.e., x1 axis), and θ represents the direction in which the Rayleigh wave propagates, as measured from magnetic north.