When conducting crosshole seismic at the Verkhnekamskoe potash deposit, head waves of high intensity are registered. The article discusses the mechanism of reflected waves generation from the propagation of head waves bottom up, which can be used for constructing a deep seismic section. The reciprocity principle makes it possible to plot such sections for both the receiving and source boreholes. Reciprocity relation makes it possible to plot these sections for both the receiving and source boreholes. The data obtained supplement the results of tomographic calculation of the velocity characteristics of the interwell space.......