a) Original (dashed) and synthetic (solid) data used in the seismological test. b) Wavelet power spectrum for the dimensionless period, P/P₀, corresponding to the synthetic signal displayed in panel a). The white solid line is the original data instantaneous period, whereas the horizontal dotted line is the period obtained from the fitting method. The red solid line denotes 99% of confidence level. c) Comparison of the original (dashed) and fitted signals with noise (solid) and without noise (dotted).