RAYLEIGH WAVE SIGNAL TO NOISE ENHANCEMENT FOR A SMALL TELESEISM USING LASA, LRSM, AND OBSERVATORY STATIONS
Abstract
Both single channel and array signal enhancement techniques have been applied to Rayleigh waves from a small Greenland Sea earthquake recorded at LASA and 13 LRSM or Observatory stations. Analysis of individual LASA long period recordings indicated that the matched filter increased S/N by more than 6 db over the mean S/N of band pass filtered (15-50 sec period) seismograms. Band pass filtering increased the mean S/N by only 1.5 db over the mean for unfiltered seismograms for LASA. Additional improvement in S/N from beam-forming both band passed and matched filtered traces approached the expected increase for uncorrelated noise provided the intersensor spacing (mesh-size) was at least 30 km. Comparable improvement was obtained for both single channel and beam- formed LRSM data. For LASA the beam-formed matched filter S/N for 13 stations was 17 db above the mean S/N for the individual band pass filtered seismograms; that for 13 LRSM stations was 15-16 db above the mean S/N of band pass filtered seismograms. Beam-forming matched filter seismograms consistently produced S/N values 7-9 db above the S/N for beam-formed band pass filtered seismograms.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 21, 1967
- Accession Number
- AD0819590
Entities
People
- D. B. Rabenstine
- S. S. Alexander
Organizations
- Teledyne Technologies