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Can teleseismic m b be affected by rock damage around explosions?
Author(s) -
Taylor Steven R.,
Patton Howard J.
Publication year - 2013
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 - 10.1029/2012gl054526
Subject(s) - scaling , seismogram , seismology , scaling law , geology , magnetic monopole , dipole , yield (engineering) , physics , geometry , mathematics , thermodynamics , quantum mechanics
Abstract Effects of rock damage on teleseismic m b are investigated with P wave synthetic seismograms using a moment dipole M zz as the equivalent elastic model for damage around buried explosions. Two manifestations of late‐time damage, cavity rebound and bulking from block rotations, are represented by model decompositions into compensated linear vector dipole and monopole sources, respectively. For high‐velocity media, P waves from damage destructively interfere with those from the explosion. This interference reduces the rate at which m b yield scales for a pure monopole source and provides a physical basis for observed scaling in hard rock, m b ~ 0.75 log[yield]. For over‐buried explosions, such as the North Korean tests, P waves from damage are weaker, and higher scaling rates are expected than explosions conducted under standard containment conditions. Our results highlight a cautionary note of transporting the same m b ‐log[yield] relation between test sites to estimate yield when source phenomenology is likely to be very different.