MODEL STUDY OF EXPLOSION-GENERATED SEISMIC WAVES

The generation of seismic waves by an explosive source in homogeneous media was investigated by two-dimensional models. The size of the effective source for compressional waves agrees well with the outer limits of the zone of circumferential cracking in a brittle medium. Prominent shear waves appear only when the source produces long radial cracks, is located near the free surface of the model, or the source is elongated. The radiation of both types of body waves is strongly modified when the source is near the surface. The P-wave spectrum can be modified by surrounding the shot with a different material. A cavity, filled with air or a solid substance, affects the signal through both its geometric configuration and the properties of the material in the cavity. The evidence from Rayleigh waves indicates that the effect of an explosion changes from a vertically applied source pulse to a buried center of compression when the source depth exceeds the radius of the zone of non-elastic behavior. When the medium is statically stressed before the shot, the body waves are modified. For relatively small strains in Plexiglas, a definite, but small, anisotropy is produced by the static strain. The presence of the static strain guides the release of energy from the explosion. Complete rupture of the sheet was produced by explosions when the stress was well below the static tensile strength. Small but distinct S-waves were produced in prestressed sheets, but could not be detected in the same material without loading. A low velocity wedge modifies wave propagation by creating a shadow zone. Diffractions into this shadow zone from the wedge tip were observed. /AUTHOR/

  • Availability:
  • Supplemental Notes:
    • Prepared for Air Force Cambridge Research Laboratories, Bedford Massachusetts; Work sponsored by Advanced Research Projects Agency.
  • Corporate Authors:

    Saint Louis University

    Department of Geophysics and Geophysical Engineering
    Saint Louis, MO  USA 
  • Authors:
    • Kisslinger, Carl
  • Publication Date: 1965-10-1

Media Info

  • Features: Figures; References; Tables;
  • Pagination: 72 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00263795
  • Record Type: Publication
  • ISBN: # 86528 Task 2
  • Report/Paper Numbers: AFCRL-65-829 Final Rpt
  • Contract Numbers: AF 19(628)-1689
  • Files: TRIS
  • Created Date: Dec 19 1974 12:00AM