Spectral Analysis of Geomagnetic Data with Continuous Wavelet Transform

The continuous wavelet transform (CWT) based on complex Morlet wavelets is used to identify magnetic sources. After summarizing the theory of CWT, we discussed the relationship between scale and frequency. In real cases, the magnetic anomalies of adjacent sources always superimpose on each other in space and frequency, making the identification of magnetic sources problematic. Therefore, we devise a scale normalization scheme to facilitate the identification of magnetic sources in strong interferences. The spectrum slices in different scales are used to determine the source distribution, and source depths can be estimated from the modulus maxima of complex coefficients.