Inversion of Pn travel times for lateral variations of Moho geometry beneath the Central Andes and comparison with the receiver functions

We inverted the Pn travel times to characterize the geometry of the Moho al ong a profile across the Central Andes (20 degreesS) where previous workers have estimated the crustal thickness using receiver functions. Contrary to receiver functions, this technique is not sensitive to the crustal V,. The refore, the comparison of the two approaches provides valuable complementar y information. Overall, our results are in good agreement with those based on receiver functions. However, some important discrepancies are observed b eneath the Western Cordillera and the Subandes, where we find crusts 10-km thinner than in previous models. We confirm that the central part of the or ogen appears to be isostatically compensated by the presence of a thick cru st. However, at both edges, the topography probably requires additional sup port, low-density mantle beneath the Western Cordillera and a strong flexur al support of the Brazilian shield beneath the Subandes.