Accession Number : AD0710894

Title :   DEEP CRUSTAL SEISMIC REFLECTIONS AT NEAR-VERTICAL INCIDENCE,

Corporate Author : ALBERTA UNIV EDMONTON DEPT OF PHYSICS

Personal Author(s) : Clowes,R. M. ; Kanasewich,E. R. ; Cumming,G. L.

Report Date : 11 APR 1967

Pagination or Media Count : 12

Abstract : Seismic reflections from discontinuities deep within the crust (reflection times of 8 to 16 sec) have been recorded along four different lines over a widespread area in southern Alberta, resulting in a total of 90 km of near-vertical-incidence profiling. Systems of geophone and hole patterns were designed to form an effective filter against long period surface waves. The data were recorded on FM analog magnetic tape and the results were digitized in order to apply digital processing techniques. Power-spectra calculations indicate that the energy of the reflected wavelets is concentrated in the range 5 to 15 Hz. Synthetic seismograms were made for comparison with field recordings and they suggest that velocity transition zones within the deep crust are less than one kilometer in vertical extent. (Author)

Descriptors :   (*STRUCTURAL GEOLOGY, ECHO RANGING), (*SEISMIC WAVES, REFLECTION), SEISMOMETERS, MOHOROVICIC DISCONTINUITY, DIGITAL RECORDING SYSTEMS, PHASED ARRAYS, POWER SPECTRA, FAULTS(GEOLOGY), CANADA

Subject Categories : Geology, Geochemistry and Mineralogy
      Seismology

Distribution Statement : APPROVED FOR PUBLIC RELEASE