Global Swave tomography using receiver pairs: an alternative to get rid of earthquake mislocation
Zaroli, C., J.J. Leveque, B.S.A. Schuberth, Z. Duputel, and G. Nolet (2014),
Global Swave tomography using receiver pairs: an alternative to get rid of earthquake mislocation,
Geophys. J. Int., 199(2), 10431057, doi:10.1093/gji/ggu312.
 Abstract
 Global seismic tomography suffers from uncertainties in earthquake parameters routinely published in seismic catalogues. In particular, errors in earthquake location and origintime may lead to strong biases in measured body wave delaytimes and significantly pollute tomographic models. Common ways of dealing with this issue are to incorporate source parameters as additional unknowns into the linear tomographic equations, or to seek combinations of data to minimize the influence of source mislocations. We propose an alternative, physicallybased method to desensitize direct Swave delaytimes to errors in earthquake location and origintime. Our approach takes advantage of the fact that mislocation delaytime biases depend to first order on the earthquakereceiver azimuth, and to second order on the epicentral distance. Therefore, for every earthquake, we compute Swave differential delaytimes between optimized receiver pairs, such that a large part of their mislocation delaytime biases cancels out (for example origintime fully subtracts out), while the difference of their sensitivity kernels remains sensitive to the model parameters of interest. Considering realistic, randomly distributed source mislocation vectors, as well as various levels of data noise and different synthetic Earths, we demonstrate that mislocationrelated model errors are highly reduced when inverting for such differential delaytimes, compared to absolute ones. The reduction is particularly rewarding for imaging the uppermantle and transition zone. We conclude that using optimized receiver pairs is a suitable, low cost alternative to get rid of errors on earthquake location and origintime for teleseismic direct Swave traveltimes. Moreover, it can partly remove unilateral rupture propagation effects in crosscorrelation delaytimes, since they are similar to mislocation effects.
 BibTeX

@article{id2040,
author = {C. Zaroli and J.J. Leveque and B.S.A. Schuberth and Z. Duputel and G. Nolet},
journal = {Geophys. J. Int.},
month = {sep},
number = {2},
pages = {10431057},
title = {{Global Swave tomography using receiver pairs: an alternative to get rid of earthquake mislocation}},
volume = {199},
year = {2014},
doi = {10.1093/gji/ggu312},
}
 EndNote

%0 Journal Article
%A Zaroli, C.
%A Leveque, J.J.
%A Schuberth, B.S.A.
%A Duputel, Z.
%A Nolet, G.
%D 2014
%N 2
%V 199
%J Geophys. J. Int.
%P 10431057
%T Global Swave tomography using receiver pairs: an alternative to get rid of earthquake mislocation
%8 sep