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This paper presents a generalised velocity model construction methodology, its computational implementation, and application in the construction of a New Zealand Velocity Model (NZVM2.0) for use in physics-based broadband ground motion simulation. The methodology utilises multiple datasets spanning different length scales, which is enabled via the use of modular subregions, geologic surfaces, and parametric representations of crustal velocity. A number of efficiency-related workflows to decrease the overall computational construction time are employed, while maintaining the flexibility and extensibility to incorporate additional datasets and refined velocity parameterisations as they become available. The methodology and computational implementation processes are then applied for development of a New Zealand Velocity Model (NZVM2.0) for use in broadband ground motion simulation. The model comprises explicit representations of the Canterbury, Wellington, Nelson-Tasman, Kaikōura, Marlborough, Waiau, Hanmer and Cheviot sedimentary basins embedded within an existing regional travel-time tomography-based velocity model for the shallow crust. [ABSTRACT FROM AUTHOR]

A 3D high-resolution model of the Quaternary geological stratigraphic sequence in the Canterbury, New Zealand region is developed utilising datasets of over 500 high-quality water well logs from a database of 29,985, and over 370 near-surface cone penetration test (CPT) records from a database of 13,670. The model, developed using geostatistical Kriging, represents the complex interbedded regional Quaternary geology by characterising the boundaries between significant interbedded geological formations as 3D surfaces. The model is examined in the form of both geological surface contour maps and vertical cross sections, where the most evident trend identified is the easterly dip caused by the dominant alluvial deposition of terrestrial sediments. The developed 3D interbedded Quaternary stratigraphy model has several applications for hydrologic modelling, earthquake-induced ground motion simulations and seismic site characterisation. For the latter case, the role of the model in constraining surface wave analysis-based shear wave velocity profiling is illustrated. [ABSTRACT FROM AUTHOR]

This paper presents the development of depth- and V s 30 -dependent parametric velocity and spatial correlation models to characterise shear-wave velocities within the geologic layers of the Canterbury New Zealand sedimentary basin. The models utilise data from 22 shear-wave velocity profiles of up to 2.5 k m depth, derived from surface wave analysis, juxtaposed with models which detail the three-dimensional structure of the geologic formations in the Canterbury sedimentary basin. Parametric velocity equations are presented for Fine Grained Sediments, Gravels, and Tertiary layer groupings. Spatial correlations were developed and applied to generate three-dimensional stochastic velocity perturbations. Dispersion curves for the stochastic models and observed velocity profiles show good agreement over a wide frequency range with the dispersion data underlying the velocity profiles used as input data, indicating that the parametric perturbed velocity profiles replicate the dispersion characteristics of the observed velocity profiles. Collectively, these models enable seismic velocities to be realistically represented for applications such as 3D ground motion and site response simulations. • Parametric functions to prescribe velocities in Canterbury sedimentary deposits. • Geostatistics are used to develop spatial correlations to add velocity perturbations to parametric models. • Velocity modelling for use in ground motion and site response simulations. [ABSTRACT FROM AUTHOR]