Based on the ambient noise horizontal to vertical spectral ratio (HVSR) technique and dense seismic array observations, combined with geological borehole data, an empirical formula for estimating sedimentary layer thickness in Shanghai is established, and a high-resolution sedimentary layer thickness model is constructed. The model shows a strong correlation with the regional geological structures of Shanghai and effectively characterizes the spatial variations of sedimentary layer thickness. Furthermore, the seismic vulnerability index of Shanghai is analyzed using the HVSR technique, and a seismic vulnerability distribution map is obtained. The results provide new constraints on the tectonic evolution and fault systems of Shanghai and offer scientific basis and technical support for seismic hazard mitigation, urban planning, and seismic design.

HVSR (horizontal to vertical spectral ratio), dense observation array, thickness of sedimentary layer; seismic vulnerability assesment