Open AccessAn experimental and numerical study of the microstructural parameters contributing to the seismic anisotropy of rocks
Author(s) -
Wendt Anke S.,
Bayuk Irina O.,
CoveyCrump Stephen J.,
Wirth Richard,
Lloyd Geoffrey E.
Publication year - 2003
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2002jb001915
Subject(s) - anisotropy , seismic anisotropy , geology , grain boundary , porosity , mantle (geology) , mineralogy , geophysics , microstructure , materials science , geotechnical engineering , composite material , physics , quantum mechanics
The elastic properties of rocks are influenced by several microstructural variables, including the lattice preferred orientation and grain shape fabric of the mineral phases, variations in the spatial distribution of the mineral phases, the properties of the grain boundaries, and the presence of porosity/fractures. Consequently, in principle, directional variations in these variables can be inferred from seismic velocity anisotropy observations. Experimental seismic velocity measurements made on rocks of well‐characterized microstructure may be used to improve the quality of such interferences. However, since most rocks are microstructurally complex, in order to interpret the measurements fully, theoretical analyses which can accommodate all the relevant microstructural variables are required. Theoretical analyses of the requisite sophistication have only recently been developed. We have tested one of these (due to Ponte Castañeda and Willis) by using it to calculate the elastic properties of an upper mantle harzburgite and by then comparing the results with experimental velocity measurements to determine if the values of those microstructural variables which are difficult to quantify (grain boundary properties, fracture shape) are physically realistic. We find that they are and conclude that the Ponte Castañeda and Willis analysis provides a powerful method for a more detailed assessment of the causes of elastic property anistropy in rocks than has previously been possible.