Upper mantle P velocity structure beneath the Baikal Rift from modeling regional seismic data

Uppermost mantle P wave velocity structure beneath the Baikal rift and southern margin of the Siberian Platform has been investigated by using a grid search method to model Pnl waveforms from two moderate earthquakes recorded by station TLY at the southwestern end of Lake Baikal. The results yielded a limited number of successful models which indicate the presence of upper mantle P wave velocities beneath the rift axis and the margin of the platform that are 2–5% lower than expected. The magnitude of the velocity anomalies and their location support the presence of a thermal anomaly that extends laterally beyond the rift proper, possibly created by small‐scale convection or a plume‐like, thermal upwelling.