Crustal thickness variation in the Andean Foreland, Argentina, from converted waves

Abstract

Local network three-component digital data from the San Juan area, Argentina, provide the first seismological images of the deep crustal structure in the Andean foreland above a horizontal segment of the subducted Nazca plate. S-to-P seismic phases converted on the Moho have been identified by analysis of seismograms formed by taking the product of the radial and vertical conponents (R*Z) from intermediate-depth earthquakes in the Benioff zone directly beneath the network. Under the Sierras Pampeanas, the Moho is estimated to be at a depth of about 52 km. Beneath the eastern Precordillera, the Moho deepens to 55/57 km and further west, beneath the central Precordillera, to 60 km. A 5° to 10° westward dip to the Moho under the Andean foreland is estimated. -from Authors

Publication Title

Bulletin - Seismological Society of America

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