ANALYSIS OF SUBARRAY WAVENUMBER SPECTRA. LARGE-ARRAY SIGNAL AND NOISE ANALYSIS.
Abstract
The ambient seismic noise at LASA was studied using high-resolution wavenumber spectra obtained for several subarrays chosen from seven noise samples covering a seven month period. A comparision of the high-resolution spectra with conventional spectra measured at two subarrays for one of the noise samples was made. Estimations of the frequency power spectra of the mantle P- wave noise and isotropic Rayleigh-wave energy were obtained. Also, estimations of the power spectra were determined for two low-velocity (V < 8.0 km/sec), fairly time-stationary, directional noise modes. One mode was present at 0.2 cps only, and the other was evident in the frequency range 0.8 to 1.1 cps. This investigation of the ambient seismic noise revealed one outstanding difference between the characteristics of subarray F1 and the characteristics of the other six subarrays studied. At 0.3 cps the apparent velocity (1.6 km/sec) of isotropic surface-mode energy at F1 was lower than the velocity of this energy (2.2 km/sec to 2.7 km/sec) at the other subarrays.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 30, 1967
- Accession Number
- AD0823784
Entities
People
- Donald B. Crouch
Organizations
- Texas Instruments