Crustal-scale seismic wave equation modeling demonstrates that wavelength-scale velocity fluctuations can dominate the seismic response over a wide range of offsets and that a wide range of velocity distributions qualitatively can explain deep seismic data. This range can be narrowed by studying the detailed petrophysical and structural properties of middle and lower crustal exposures. The Ivrea Zone, in the Southern Alps, is a well-studied sliver of extended lower continental crust brought into its present upright position as a result of late Alpine lithospheric shortening. The high degree of structural and petrophysical complexity and in particular the limited exposure of the Ivrea Zone favor a statistical rather than deterministic approach to develop a two-dimensional crustal-scale seismic model. For this purpose we digitized two 1:25,000 geological maps from the central Ivrea Zone on a 60-m grid. We find that the Ivrea Zone is characterized by a bimodal velocity distribution, and a band-limited self-affine structure having a fractal dimension of 2.7, a characteristic horizontal scale of 500 to 1000 m, and an aspect ratio around 4.0. Assuming statistical stationarity, a realization of this stochastic model was used to develop synthetic seismograms typical of ''Ivrea-type'' lower continental crust. Our results indicate that (1) Ivrea-type lower crust can explain qualitatively commonly observed lower crustal reflectivity, (2) relatively minor changes in bulk composition and/or metamorphic grade may lead to dramatic changes in reflectivity, which cannot be explained by current generic models on the origin of lower crustal reflections, and (3) travel time interpretation of the synthetic wide-angle data may lead to erroneous large-scale velocity structures. ¿ American Geophysical Union 1993