Calibration of the Sonseca array with large magnitude regional and teleseismic events
In order to calibrate the Sonseca station, a 19-element short-period seismic array with a 9 km diameter circular aperture located in central Spain (39.68N, 3.96W), wavefield measurements made on observed seismic phases are compared with expected values. Thirty-five well-recorded regional and teleseismic events are used to study bearing and phase velocity estimation properties. Preliminary results indicate that in general the Sonseca array performs well for both regional and teleseismic events for frequencies less than 5 Hz using standard array signal processing techniques. Main findings of this study are: (1) A systematic bias is observed in bearing estimates; the bias is a function of the true bearing for events from the easterly directions of the array and can be mitigated with a simple bias correction. Using a least-squares quadratic polynomial fit, the bearing estimation error can be reduced to less than two or three degrees. (2) Measured signal and noise coherence functions and beamforming suggest that for regional events improved SNR is obtained by beamforming in the frequency band of 0.5 to 4 Hz with a resulting array gain as high as 10 dB. (3) Because the element spacing of Sonseca array corresponds to that of a sparse regional array, spatial aliasing can be observed in narrowband f-K analysis at the higher frequencies. We compare performance of narrowband and broadband frequency-wavenumber (f-k) analysis and suggest preliminary recipes for f-k and beamforming analysis.
- Research Organization:
- Lawrence Livermore National Lab., CA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 273791
- Report Number(s):
- UCRL-ID--125023; ON: DE96014097
- Country of Publication:
- United States
- Language:
- English
Similar Records
Preliminary evaluation of the Korean seismological research station short-period array. Technical report
Optimized filtering of regional and teleseismic seismograms: results of maximizing SNR measurements from the wavelet transform and filter banks
Relative Lg and P-coda magnitude analysis of the largest Shagan River explosions. Final report, 2 April-30 October 1984
Technical Report
·
Tue Jul 29 00:00:00 EDT 1975
·
OSTI ID:7347102
Optimized filtering of regional and teleseismic seismograms: results of maximizing SNR measurements from the wavelet transform and filter banks
Conference
·
Tue Jul 15 00:00:00 EDT 1997
·
OSTI ID:610743
Relative Lg and P-coda magnitude analysis of the largest Shagan River explosions. Final report, 2 April-30 October 1984
Technical Report
·
Thu Dec 27 23:00:00 EST 1984
·
OSTI ID:5560808