Right to left: the first track DsubM is the difference in ms between the picked data P-wave arrival and the ray-trace modeled arrival; the drift is within ±1 ms. The 2nd track shows the layered velocity profile Vp in red and VSP interval velocity in blue. The 3rd track shows the model P-down inclination angle in purple, and data measured inclination in blue. The 4th track shows the model P-down azimuth angle in purple, and data measured azimuth in blue. The trace data on the leftmost track is the minimized P-down component which holds the majority of the P-S down signal. Figure reproduced from Figure 3.5.3 of Bailey [8].