1887
Volume 32 Number 1
  • E-ISSN: 1365-2478

Abstract

A

The most common source of seismic energy is an explosion at some depth in a borehole. The radiated waves are reflected not only at the subsurface layers but also at the free surface. The earth's surface acts as a generator of both P‐ and S‐waves.

If the source depth is much less than the dominant wavelength the reflected waves resemble closely the waves generated by a single force. Theoretical seismograms were computed with different methods to look for the relevance of the surface‐reflected waves. The numerical experiments show reflected shear waves even for small shotpoint—receiver distances. Due to their polarization these waves can be detected most easily on in‐line horizontal geophones. The existence of these waves was examined during a conventional survey in Northern Germany. Conventional data analysis shows a large variability in the ν ratio. The method used here produced a shear‐wave section with a rather good signal‐to‐noise ratio down to 4 s S‐wave reflection time.

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2006-04-27
2020-07-15
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  • Article Type: Research Article
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