BDSN Noise Summary
One of the tools used by the BSL to monitor the health of the network is the analysis of the power spectral density of the background noise. Once a week, the power spectral density (psd) is computed in the period ranges 16-32, 32-64, 64-128, 128-256, and 256-512 seconds is computed for all the broadband stations. This weekly assessment is reviewed by the BSL staff and is available on the Web.
For comparision, here are three cumulative summary plots for the vertical, north, and east components in the band from 32-128 seconds. These figures display time series of the PSD results for the current calendar year. In order to show all the stations on the same plot, the mean has been removed from each time series and is displayed on the right-hand side. The offset between the stations is 20 dB.
|Cumulative PSD results|
In the table below, we provide cumulative psd plots for each station, summarizing the results for the year to date. In each figure, the vertical component psd is plotted with blue diamonds, the north component psd with red squares, and the east component psd with green circles. The results are presented in the 5 different frequency bands, and the USGS/Albuquerque low noise model is plotted as a dashed line in each.
In all figures, the PSD units are in dB (decibel) relative to 1 (m/s**2)**2/Hz. These plots are updated weekly.
The PSD results were computed using an algorithm developed by BSL staff seismologist Bob Uhrhammer. The software used compute the power spectral density is available to the public.
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