LP and RN data
Åknes Rock Slide
NORSAR Power Density Spectra
We compute hourly power spectral density (PSD) for each channel using Welch's method:
The seismograms are not instrument-corrected and therefore in units of counts. The unit of the PSD is accordingly counts**2/Hz
We display the logarithm (log10) of the PSD in monthly panels (see example for NAO00_SZ above). The x-axis is time in units of days the y-axis is frequency in [Hz] and the PSD is color-coded (blue: low amplitude, red. high amplitude). In order to increase the dynamic resolution of the plots the average PSD (computed from all hourly PSDs in the panel) has been substracted. The average PSD is overlaid on the plot as a red curve. Its scale is indicated with red markers on top and on the bottom of the plot.
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