Application of second arrivals in seismic tomography inversion for the crustal structure study

Standard seismic tomography is based on the first arrival refracted Pg- and Pn-waves travel times and as a result gives a smooth model of the structure. Sharp discontinuities, particularly the Moho, as well as lower crust, are poorly constraint. The paper presents a modification of the standard method which allows to use later arrivals of crustal Pcr waves together with the first arrival travel times. They give better coverage by rays and better model for the whole crust. Results are illustrated by synthetic models and interpretation of experimental data from POLONAISE'97 profile P4.