Analysis of Short-Period Seismic Signals and Noise Recorded at LASA and TFO
TELEDYNE GEOTECH ALEXANDRIA VA SEISMIC DATA LAB
Pagination or Media Count:
Short-period beams were formed for twenty-four events recorded at both the LASA and TFO arrays. The mean RMS noise in the frequency range 0.4-3.0 Hz for the LASA beams was 0.16 millimicron, and for the TFO beams 0.13 millimicron. Noise reduction by beam formation in the range 0.4-3.0 Hz varied from 17 to 23 db for LASA, from 12 to 18 db for the 37-sensor TFO array, and from 6 to 14 db for the 19-sensor TFO subarray. Averaging over several source regions in the distance range 25 degrees delta90 degrees, the signal-to-noise ratio for LASA was about one db better than that of TFO for common events. The improvement in signal-to-noise ratio for LASA beams was found to increase 4 db by changing the number of sensors employed in the beams from 48 to 340 while keeping the minimum sensor spacing delta or 1km.
- Seismic Detection and Detectors