New Zealand Wide model 2.3 seismic velocity model for New Zealand

19-Sept-2024 Full uncompressed versions of the New Zealand Wide 2.3 velocity, Qs and Qp model Tables can be obtained from zenodo.org/records/13799996

New Zealand Wide velocity model 2.3 has seismic velocity for New Zealand developed from local-earthquake tomography studies. It incorporates results from the southern South Island, published in Tectonics, using joint inversion of travel times and ambient noise derived group velocities (Eberhart-Phillips, et al., 2021, 2022).  The results from that study have been interpolated and merged into the previous New Zealand Wide model 2.2 (zenodo.org/record/3779523)

The model is provided in tables, where the Spread Function (SF) shows the resolution, such that where SF<4, there is little information.

vlnzw2p3dnxyzltln.tbl.txt

There is also a simul format velocity file.

vlnzw2p3.mod.txt

And map plots with white lines denoting limits of adequate data, from the 2022 Southern South Island paper, and also for all New Zealand.

Figs_SouthernSI_Tect.pdf

mapvpvpvsnzw2p3.pdf

Velocities any point within the 3D gridded models are defined by linearly interpolating between nodes.

The models use Transverse Mercator coordinate transformation with a central meridian= 173, and counterclockwise rotation of 140.  Earth-flattening transformation is used for velocity during ray-tracing. The depths are relative to sea-level. Density has been included in the velocity table, by using an empirical relationship (Gardner et al., 1974; Hill, 1978).