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We apply inversion methods to first arriving P waves from explosive source seismic data collected along line 1 of the Los Angeles Region Seismic Experiment (LARSE), extending northeastward from Seal Beach, California, to the Mojave Desert, in order to determine a seismic model of the upper crust along the profile. We use resolution information to quantify the extent of blurring in the LARSE images and to smooth a damped least squares (DLS) image by postin-version filtering (PIF). Most of the original data fit is preserved while minimizing model artifacts. We compare DLS, PIF, and smoothing constraint inversion images using both real and synthetic data. A preferred PIF image includes larger-scale features in the smoothing constraint inversion image and finer-scale features in the DLS inversion image that are consistent with geologic information. We interpret principal model features in terms of geology, including faulting. The maximum depth of low-velocity sedimentary and volcanic rocks in the Los Angeles basin is 8-9 lan and in the San Gabriel Valley is 4.5-5 km. A horst-like uplift of basement rocks occurs between these basins. The northeastern boundary of the San Gabriel Valley is imaged as a tabular, moderately north dipping low-velocity zone that projects to the surface at the southernmost trace of the Sierra Madre fault system. In the central and southern San Gabriel Mountains, velocity-depth profiles are consistent with intermediate-velocity mylonites overlying lower-velocity Pelona Schist along a shallowly southwest dipping Vincent thrust fault. Tomography does not provide a definitive dip for the San Andreas fault but, combined with other LARSE results, is consistent with a vertical to steep northeast dip.