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Interpretation of the low velocity zone in terms of the presence of thermally activated point defects
Author(s) -
Shaw George H.
Publication year - 1978
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/gl005i008p00629
Subject(s) - interpretation (philosophy) , mechanics , thermal , thermodynamics , geology , speed of sound , point (geometry) , electrical resistivity and conductivity , olivine , physics , materials science , mineralogy , geometry , mathematics , quantum mechanics , computer science , programming language
Experimental and theoretical work indicates that point defects can significantly affect sound velocities. Since point defects may exist in thermal equilibrium, their effect on sound velocities may be calculated as an activation phenomenon. Alternatively, activation parameters may be calculated from sound velocity data. Because of the shape of the goetherm it is possible to treat the low velocity zone using the theory of activated processes. The activation parameters calculated from V p and V s are in reasonable agreement with one another and with values determined from laboratory experiments on electrical conductivity of olivine and orthopyroxene.