(a) Example of horizontal component seismograms with shear-wave splitting, recorded at station KZR. Seismograms are rotated to the leading/lagging coordinate system, i.e., one axis is rotated to the direction at which the cross-correlation coefficient is maximized. Two quasi S-phases in the seismograms have similar shapes and shift by 85 ms, the computed value of DT. (b) Particle motion plot containing S-wave first motion shown in Fig. 2(a). Initial polarization is N145°E, the computed value of Φ, and particle motion changes abruptly to the orientation N235°E at the arrival time of the lagging S-wave. (c) Contour plot of cross-correlation coefficient. Plus shows 95% confidence region.