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Effects of shock‐induced tensile failure on m b ‐ M s discrimination: Contrasts between historic nuclear explosions and the North Korean test of 9 October 2006
Author(s) -
Patton Howard J.,
Taylor Steven R.
Publication year - 2008
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2008gl034211
Subject(s) - ultimate tensile strength , amplitude , physics , isotropy , tensile testing , materials science , seismology , geology , composite material , optics
Rayleigh wave excitation is studied for an explosion source model consisting of a superposition of isotropic (monopole), tensile failure, and tectonic release point sources. The body‐force representation for shock‐induced, deep‐seated tensile failure is a compensated linear vector dipole CLVD, where the relative strength of the CLVD is given by an index K . Rayleigh wave amplitudes are reduced owing to destructive interference between an explosive monopole and a CLVD source with vertical axis of symmetry in extension ( K > 1). The effect of tensile failure on M s is to enhance the explosion‐like characteristics on a plot of m b ‐ M s . This model suggests that the success of the m b ‐ M s discriminant results from the fact that nuclear tests were conducted under containment practices for which tensile failure is ubiquitous, while the North Korean nuclear test of 9 October 2006 is a harbinger of poor m b ‐ M s performance when tensile failure is completely suppressed.