Introduction
As part of the operation of the Saint Louis University broadband seismic network, all sensors received for the network are evaluated for noise performance at the SLm station on the university campus. The procedure follows the paper A direct method for caluclating instrument noise levels in side-by-side seismometer evaluations by L. Gary Holcomb of the USGS (USGS Open-File Report 89-214)./
The operational testing requires a comparison of two data streams from different sensors. We accomplish this by using two 6 channel Quanterra Q-680 data acquisition systems. The SLM H channel is an STS-2 seismometer. Another Q-680 had two CMGe-ESP sensors. The cross correlation analysis was performed among the three sensors.
This page presents the results for Day 038 2001 and a direct comparison of CMG3-ESP SN 3163 L channel) to CMG3-ESP SN 3164 (H channel). Day 038 was chosen because of low teleseismic activity. 17 data segments are taken hourly starting at 0000 through 1700. 8192 time samples are used (~90 sec for 20 sps data stream) and 8192 sec for the 1 sps data stream. The noise results from the 20Hz and 1Hz data streams overlab at a 10 second period.
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Noise test of CMG3-ESP SN3163. The Blue does are the estimates of ground noise. The red dots are the estimate of the instrument self noise. The black curves are the Albuquerque low and high noise models.
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