Crustal structure in Chile and Okhotsk Sea regions

In the region of Chile the refraction and wide angle reflection migration, applied to CINCA seismic data, enable to reveal some new peculiarities of the crustal structure which do not agree with the simplified classical model of the oceanic lithosphere subduction. A fault zone separated the oceanic and continental crusts are imaged in the migration section. A subhorizontal detachment is found in the continental crust.In the Okhotsk Sea region the reinterpretation of the old DSS data shows a block structure of the crust and a complicated system of faults along the Kuril Islands and between the Sakhalin Island and the South-Okhotsk basin. The crustal type changes: the basin crust is of oceanic type whereas in all other parts of the Okhotsk Sea it is of continental or subcontinental types. The lower velocities are typical of the middle crust of the Ockotsk Sea but along both sides of the Kuril Islands high velocity bodies are intruded in the crust showing the process of crustal basification. In the uppermost mantle beneath the Sakhalin Island a reflected boundary dipping from the Moho to a depth of 50 km is revealed.