Abstract:

Local wavenumber method is a widely used method in the interpretation of magnetic fields, the previous local wavenumber methods need to compute the derivatives of local wavenumber in the inversion, which increase the effect of noise obviously, and bring the errors to inversion results. The authors proposed using the simple combinations of different locations and heights of local wavenumber of magnetic anomaly to compute the depth and structural index of the causative source, and these methods do not need to compute the derivatives of the local wavenumber, which reduce the effect of the noise, and increase the stability of the inversion results. The new methods are demonstrated on theoretical magnetic field data without and with random noise, and the difference between the inversion results and theoretical values is less than 5% of the theoretical values. The practical application of the new methods is tested on real magnetic anomaly from Sichuan basin, Southwest China, the inversion results are consistent with the results computed by the Euler deconvolution of analytic signal. The proposed local wavenumber methods can finish the inversion of magnetic data effectively.

Key words: magnetic fields, depth, structural index, derivatives, local wavenumber