Development of a 3D Shear Wave Velocity Model for Metro Vancouver Considering Geological Heterogeneity and Spatial Correlation

ABSTRACT: Shear wave velocity (VS) is a critical soil property in seismic microzonation, reflecting soil stiffness and influencing seismic wave propagation and ground shaking. In Metro Vancouver, a three-dimensional (3D) geological model is developed using a comprehensive regional geodatabase compiled over 6 years from a wide range of datasets to produce Holocene post-glacial sediments and Pleistocene and older interglacial/glacial sediments VS variability. Passive-source seismic testing, including ambient vibration array (AVA) and microtremor horizontal-to-vertical spectral ratio (MHVSR) methods, was instrumental in delineating glacial and bedrock sub-topography. Then, spatial prediction of VS within the 3D geological model is accomplished to generate a 3D Vs model. Depth-related VS trends were removed to counter overburden stress effects. The normalized VS values were analyzed to study spatial variability within each geological unit. Using geostatistical modeling, VS values were predicted in 3D, addressing geological heterogeneity and preserving spatial correlation.