Figure 4From: Properties of GPS noise at Japan islands before and after Tohoku mega-earthquakeGraphics of wavelet-based power spectra (blue lines) after coming to increments for 2 examples of East GPS time series before Tohoku earthquake. Red lines present best fit lines in double logarithmic axes. Spectral index correspond to slope of red lines. Case (a) present large (taking into account the sign of the value) spectral index, whereas case (b) corresponds to small index.Back to article page