Joint inversion of receiver function of teleseismic body waves and local group velocity dispersion curves beneath ESPZ and PMSA stations (Antarctic Peninsula)

A database of 70 teleseismic earthquakes is used to infer the lithospheric structure beneath PMSA and ESPZ stations, deployed in Antarctic Peninsula respectively south of the intersection of the Hero Fracture Zone (HFZ) with the South Shetland Trench (SST), and at the extreme tip of the Antarctic Peninsula. The inversion of receiver function of teleseismic body waves is constrained by a group velocity tomographic study in the Scotia Sea region in order to minimize the non-uniqueness problem that results from the velocity-depth trade-off. The high noise level, typical of the oceanic environment, is overcome by stacking teleseisms with common receiver-station azimuthal angle and distance, and by selecting events with mb > 6.0 within a range of distances between 30° to 85°. S-wave velocity models found beneath ESPZ and PMSA stations have a common velocity profile characterized by a large velocity gradient zone in the upper crust and by a smaller velocity gradient from the lower crust to the upper mantle. The depth of the crust-mantle transition zone beneath ESPZ and PMSA is about 37 km and 40 km, respectively.