Five Polish Seismic Expeditions to the West Antarctica (1979–2007)

The chapter presents results of five Polish expeditions which realised an extensive programme of wide-angle refraction experiments in the northern Antarctic Peninsula region in the period of 1979–2007. The main achievement was the interpretation of materials collected along 20 deep seismic sounding profiles located along western part of the Antarctic Peninsula. Additionally, few shallow profiles in the area of Deception Island and the net of 10 reflection profiles from the Bransfield Strait and Drake Passage, and 3D experiment in the Admiralty Bay (King George Island) were carried out. Crustal velocity models extending across the Antarctic continental shelf between Adelaide Island and Bransfield Strait show typical continental crustal structure, with crustal thicknesses of 36–42 km near the coast, decreasing to 25–28 km beneath the outer continental shelf. Farther north, in the Bransfield Strait region, the models describe a crustal structure with the Moho dipping southeastward from a depth of 10 km beneath the South Shetland Trench to 40 km under the northern tip of the Antarctic Peninsula. Beneath the trough of the Bransfield Strait, the presence of a high-velocity body, with compressional-wave velocities exceeding 7.0 km/s, was detected at a depth range of 6–32 km.