摘要：A scheme is proposed for calculating the piezomagnetic fields that accompany the propagation of seismic waves through a non-uniformly magnetized crust.Examples of the calculations are provided.Generally, the calculation of the co-seismic piezomagnetic fields involves laborious three-dimensional volume integrals, even if the magnetization structure is two-dimensional.However, the calculation can be simplified by taking the Fourier transform of spatial distributions of the field into consideration.As an example, we have performed calculations for both the non-uniformly and uniformly magnetized crust with an intensity of 10 A/m.The incident seismic wave is considered to consist of Rayleigh waves with an amplitude of 5 cm.The amplitudes of the piezomagnetic signals arising from uniformly magnetized crust are up to 0.2 nT, whereas those arising from non-uniformly magnetized crust are as large as 0.5 nT.This result indicates that the piezomagnetic field may be a plausible mechanism of generating co-seismic changes in the magnetic field with detectable amplitudes for large earthquakes, provided that the observation site is located near the magnetization boundaries. Key words Enhancement piezomagnetic effect magnetic anomalies seismic waves co-seismic variations Fourier transforms.
