ESTABLISHMENT OF A LONG-PERIOD SEISMOGRAPH NETWORK UTILIZING MAGNETIC TAPE RECORDING
Abstract
A worldwide network of long-period seismographs recording on magnetic tape has been established, including stations at Mt. Tsukuba, Japan; Honolulu, Hawaii; Uppsala, Sweden; Huancayo, Peru; College, Alaska; Canberra, Australia; and Palisades, New York. At these stations the amplified outputs of 3-component 15-second transducers are recorded at two gain levels on tape recorders operating at .06 inches per second. These units provide 16 2/3 days of recording time per reel with a bandwidth of DC to 10 cps and a signal-to-noise ratio of 60 db. This worldwide network continues in operation at the present time. Analysis techniques developed and/or utilized for data analysis in this program include: (a) high-, low- and band-pass filtering; (b) inverse filtering; (c) Fourier analysis, (d) rotation of instrumental axes, (e) cumulative energy, (f) longitudinal-vertical product for particle motion, (g) angles of emergence and azimuth, and (h) direction of microseism approach and beam width. Studies of particular interest to the VELA-UNIFORM program include: (a) contouring of total energy and ratio of high-frequency-to-low-frequency energy for the Hardhat and Gnome underground nuclear events and comparison with data from the New Madrid and Hebgen Lake earthquakes, (b) the determination of experimental radiation patterns for Love and Rayleigh waves (both amplitude and phase) for several underground nuclear explosions and the comparison of the observed data with theoretical models.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1965
- Accession Number
- AD0622794
Entities
People
- Paul W. Pomeroy