Shear-wave velocities under the Transantarctic Mountains and Terror Rift from surface wave inversion

Rayleigh wave data between 20 and 120s period recorded in the western Ross Sea region of Antarctica are inverted using the waveform inversion techniqu e described in Passier and Snieder [1995]. From the data we extract estimat es of local S velocity structure beneath the Transantarctic Mountains and t he Terror Rift. The shear wave velocities found are up to 6% slower than th e PREM model at between 40 and 160 km depth, depending on the propagation p ath, providing evidence of an anomalously warm upper mantle beneath the Ter ror Rift and, to a lesser extent, beneath the front of the Transantarctic M ountains.