Optimization of the preselection algorithm for travel-time data inversion

Seismic tomography based on body-wave travel-time inversion involves the solution of unstable problems in many applications, where the instabilities are chiefly due to the ill-conditioned mathematical operators that must be inverted in order to compute the wave-velocity fields. In problems where the region under study is discretized into cells with uniform velocity, an efficient way to mitigate the instabilities was proven to be an appropriate preselection of the seismic rays. In this paper an enhanced version of the preselection algorithm is given which essentially makes the selection procedure faster and more efficient.