BSL: 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.

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.

Station Name	Cumulative PSD
ARC	1999	2000	2001	None	None	None	None
BDM	1999	2000	2001	2002	2003	2004	2005
BKS	1999	2000	2001	2002	2003	2004	2005
BRIB	1999	2000	2001	2002	2003	2004	2005
BRK	1999	2000	2001	2002	2003	2004	2005
CMB	1999	2000	2001	2002	2003	2004	2005
CVS	1999	2000	2001	2002	2003	2004	2005
FARB	1999	2000	2001	2002	2003	2004	2005
HOPS	1999	2000	2001	2002	2003	2004	2005
HUMO	None	None	None	None	2003	2004	2005
JCC	None	None	2001	2002	2003	2004	2005
JRSC	1999	2000	2001	2002	2003	2004	2005
KCC	1999	2000	2001	2002	2003	2004	2005
MHC	1999	2000	2001	2002	2003	2004	2005
MIN	1999	None	None	None	None	None	None
MNRC	None	None	None	None	2003	2004	2005
MOD	None	2000	2001	2002	2003	2004	2005
ORV	1999	2000	2001	2002	2003	2004	2005
PACP	None	None	None	None	2003	2004	2005
PKD	1999	2000	2001	2002	2003	2004	2005
POTR	1999	2000	2001	2002	2003	2004	2005
SAO	1999	2000	2001	2002	2003	2004	2005
WDC	1999	2000	2001	2002	2003	2004	2005
WENL	1999	2000	2001	2002	2003	2004	2005
YBH	1999	2000	2001	2002	2003	2004	2005

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.