The detection and location of near-regional seismic disturbances by the Eskdalemuir array: A study using noise and signal correlations
Abstract
Recordings of noise and signals from seismic disturbances at near regional (0 to 500 km) disturbances are used to investigate the noise and signal correlations for the Eskdalemuir array. The observed spatial variation of the signal and noise correlations enable predictions to be made on the beamforming capability of the array in terms of potential signal to noise gain. Predicted gains are 3.8 in the 2 to 4 Hz band falling to 3.0 in the 6 to 8 Hz band when using the full 20 seismometer array. The uniform spacing of the seismometers in the array leads to strong grating lobes in the array response which in turn can lead to ambiguities or aliasing in estimates on the slowness and backbearing of incoming signals. This problem is considerably reduced if only signals with slowness less than 0.2 s/km (apparent velocity in excess of 5 Km/s) are considered. Standard errors on the backbearing estimates for near regional signals are found to be in the range 3 to 4 degrees.
- Publication:
-
Unknown
- Pub Date:
- February 1991
- Bibcode:
- 1991dlnr.rept.....L
- Keywords:
-
- Correlation Detection;
- Nuclear Explosions;
- Position Indicators;
- Seismic Waves;
- Seismographs;
- Seismology;
- Signal Processing;
- Signal To Noise Ratios;
- Arrays;
- Collimation;
- Error Analysis;
- Prediction Analysis Techniques;
- Spatial Distribution;
- Geophysics