Abstract:
New analyses of teleseismic body waves from moderate
earthquakes in western Argentina demonstrate that active
shortening of the Andean foreland occurs on reverse faults
extending to 40–50 km depth. Existing crustal‐scale
models of foreland deformation invoke thin‐skinned fault
geometries, which root into an east‐dipping mid‐crustal
décollement. Whereas thin‐skinned thrust sheets dominate
shallow‐crustal structure, seismological and geological data
illustrate that planar reverse faults and pure‐shear deformation
involving more than 75% of the crust characterizes this
thick‐skinned structural province.
