Mapping the thickness of crust and lithosphere of South America

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The thickness of the lithospheric plates is one of the most important keys in plate tectonics. Yet high-resolution seismic observations of the lithosphere with body waves is still rare, probably because of the gradient nature of the lithosphere-asthenosphere boundary (the LAB) or problems connected with wide-angle observations of the LAB as an upper boundary of a low-velocity zone (asthenosphere). The recently developed S receiver function method appears to provide an ideal means to observe the LAB. In the last decade a number of German (SFB 267) and US temporary seismic experiments have been operated in the Andes and have collected a large amount of data. We propose here to apply the S receiver function method to these data and to the permanent stations distributed in the entire South American continent to measure the thickness of the lithosphere in South America. This technique, although still new, has proven very useful for mapping the LAB at the Hawaiian and Iceland plume tracks and across the continental collision zone Tien Shan and Pamir. Knowledge about the structure of the entire lithosphere, not only the crust, will significantly improve our understanding of plate tectonics of South America.