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IN SITU SEISMIC MEASUREMENTS OF CRACK ANISOTROPY IN THE CARBONIFEROUS LIMESTONE OF NORTHWEST ENGLAND *
Author(s) -
BAMFORD D.,
NUNN K. R.
Publication year - 1979
Publication title -
geophysical prospecting
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.735
H-Index - 79
eISSN - 1365-2478
pISSN - 0016-8025
DOI - 10.1111/j.1365-2478.1979.tb00973.x
Subject(s) - anisotropy , geology , carboniferous , gemology , seismology , igneous petrology , in situ , economic geology , seismic anisotropy , engineering geology , mineralogy , mantle (geology) , petrology , geophysics , metamorphic petrology , paleontology , tectonics , volcanism , optics , physics , structural basin , meteorology
A bstract Seismic velocity anisotropy is predicted for cracked rocks containing either a naturally‐occurring or an artificially‐induced preferred orientation of cracks. Methods developed for the study of velocity anisotropy in the uppermost mantle have been applied to the in situ measurement of P‐wave velocity anisotropy in fractured Carboniferous Limestone in Northwest England. At three different sites, first‐arrival travel‐time data has been obtained using conventional refraction equipment and a weight‐drop source. Velocity anisotropy of 15–29% is identified with directions of maximum and minimum velocities that can be broadly related to previously mapped orientations of joints.