Open AccessCrust and upper mantle shear velocities from controlled sources
Author(s) -
Hales A. L.,
Muirhead K. J.,
Rynn J. M. W.
Publication year - 1980
Publication title -
geophysical journal of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0016-8009
DOI - 10.1111/j.1365-246x.1980.tb02644.x
Subject(s) - geology , crust , mantle (geology) , seismology , continental crust , shield , continental shelf , geophysics , discontinuity (linguistics) , shear (geology) , oceanography , paleontology , mathematical analysis , mathematics
b A two ship refraction profile was undertaken on the Australian continental shelf during the Banda Sea geophysical program, carried out by the Woods Hole Oceanographic Institution, the Scripps Institution of Oceanography and the Geological Survey of Indonesia. S waves originating close to the sea bottom were observed to distances of up to 1150 km at an array of stations in northern Australia. These observations are interpreted as implying S mantle velocities of 4.60 km s ‐1 from a depth of 45 km to a depth of 76 km and 4.72 km s ‐1 below a depth of 76 km. Ratios of the P and S travel times (V p /V s ) have been determined to be 1.74 in the crust rising to a value of greater than 1.79 below a velocity discontinuity at a depth of 200 km. It is inferred that this high value arises because the effect of temperature is greater for S than for P . Using the data from this and other studies in the shield region of Northern Australia it has been found that the S travel times are significantly less than predicted by the Jeffreys—Bullen tables.