This research investigates the different scales of crustal heterogeneity. A method for estimating the characteristic smaller scales of crustal heterogeneity directly from reflection seismic data is applied to the COCORP dataset. Smaller scales of crustal heterogeneity range between 250-800 m. The method is also applied to another reflection dataset that images extended crust similar to the Basin and Range and the results are compared. To determine the larger scale of heterogeneity, 2-D velocity models for the PASSCAL Basin and Range E-W refraction profile are derived using 2-D traveltime inversion. Combined stochastic and deterministic models that represent crustal velocity heterogeneity are generated using the results from the characteristic scale estimation and 2-D inversion. From these models, finite-difference synthetic seismograms are generated and a preferred model is chosen because the corresponding synthetic seismograms reproduce well the characteristic features of the seismic wavefield seen in the PASSCAL data.