Teleseismic recordings of several seismograph stations are processed with the aid of the S receiver function technique [Farra and Vinnik, 2000]. The data provide evidence of a strong reduction of S velocity at a depth around 360 km (station BOSA) and 280–300 km (station LBTB) in the East of southern Africa. A similar feature is found in the Tunguska basin of the Siberian platform from the recordings of station NRIL. In both regions large volumes of flood basalts have been erupted 190–180 Ma and 250 Ma ago, respectively. The coincidence suggests a causal relation between the two phenomena. This relation implies that the low‐velocity anomalies migrate with the plates.