Noise Study for TFO Extended Short-Period Array
Technical rept. no. 5
TEXAS INSTRUMENTS INC DALLAS SERVICES GROUP
Pagination or Media Count:
Seismic data was digitally collected from the recently extended short-period array of the Tonto Forest Observatory during the summer of 1968 and the winter of 1969. An analysis of the data was made to characterize the ambient noise field from each period and to determine time-and space-stationarity of the fields. The effectiveness of multi-channel filter processing on the extended array was also measured. Several contributors to the ambient noise field could be defined in both of the periods analyzed and appeared to be both time-and space stationary. Other contributors, due primarily to atmospheric storm or pressure activity, were not stationary and could be related to its generating source. Multi-channel filtering of the extended array could not provide any significant improvement over simple beamsteering at frequencies of interest greater than .8 Hz. At lower frequencies, the amount of improvement obtained by MCF processing relative to beamsteering was directly related to the increase in noise level due to the non-stationary contributor of the noise field.
- Seismic Detection and Detectors