The thickness of sediments above bedrock controls seismic site response and groundmotion amplification, but is difficult to map at high resolution in urban areas with sparse boreholes. This control is captured by the shallow equivalent thickness—the effective sediment-layer thickness that reproduces the observed near-surface resonance, rather than the purely geometric depth to bedrock. Conventional horizontal-to-vertical (H/V) inversions assume a single homogeneous layer, while purely data-drive