We employ differential adjoint tomography to image the San Gabriel Basin, Chino Basin and San Bernardino Basin in the northern Los Angeles to suppress the effects of unknown noise sources. We obtain Empirical Green’s Function of Love wave with high Signal-to-Noise Ratio. A region wise optimization strategy is implemented to address regional sensitivity kernel incompatibility and thus improve resolution in the region with suboptimal data quality. Our results align well with known structures and reveal more details than previous studies in this region. Beyond delineating basin structures, we identify a high-velocity channel at the San Jose Fault. Diffuse low-velocity anomalies detected at the Fontana seismicity region provide evidence for fluid migration. Lastly, we identify a concentrated low-velocity anomaly between 0.8 km to 4 km depth beneath Puddingstone Reservoir, potentially indicating groundwater seepage, which may influence seismicity in the area.