Open AccessTau estimates for mantle P ‐ and S ‐waves from global travel‐time observations
Author(s) -
Lee Richard C.,
Johnson Lane R.
Publication year - 1984
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.1984.tb02214.x
Subject(s) - confidence interval , mantle (geology) , travel time , geology , geodesy , confidence region , statistics , seismology , geophysics , mathematics , engineering , transport engineering
Summary Travel‐time data from the ISC Bulletin were used to determine a τ( p ) confidence region for mantle P ‐ and S ‐waves. One year of P data, amounting to approximately 108000 travel times, and four years of S data, amounting to approximately 75000 travel times, were used. Geometrical path corrections were applied to place all sources and receivers at a common radius of 6338 km. A preliminary test was devised and applied to the travel‐time data to determine if they were suitable for the estimation of τ( p ). This criterion precluded construction of complete tau functions for the mantle, particularly the upper mantle. Thirty‐five confidence intervals for the mean τ( p ) were computed at the 99.9 per cent confidence level from the P data, and 23 were computed from the S data. Most confidence interval widths were less than 0.2 s for P ‐waves, and less than 0.8 s for S ‐waves. Comparison with computed τ( p ) for several published velocity models indicates significant differences among the models in the τ(p) domain.