This is a 3D velocity model of the North Island of New Zealand derived using earthquake-based adjoint tomography.
|Title||New Zealand Adjoint TOMography velocity model (North Island)|
|Type||3-D Tomography Earth Model|
|Sub Type||Shear-wave velocity (km/s) and Compressional-wave velocity (km/s)|
|EMC Data Revision||r0.0 (revision history)|
|Short Description||This is a 3D velocity model of the North Island of New Zealand derived using earthquake-based adjoint tomography. The starting model is defined as the ray-based NZ-Wide2.2 Velocity Model from Eberhart-Phillips et al. (2021). To derive this velocity model, we iteratively improve fits between earthquake observations from New Zealand-based broadband seismometers and synthetically generated waveforms from spectral element simulations. The waveform bandpass of interest is 4-30s.
This velocity model defines the following quantities: Vp (km/s), Vs (km/s), density (kg/m3), Qp and Qs, however only Vp and Vs are updated during our inversion. The remaining quantities are defined by the starting velocity model.
|Authors:||Bryant Chow, Victoria University of Wellington, Wellington, New Zealand
GNS Science, Lower Hutt, New Zealand
(Now at University of Alaska Fairbanks)
Yoshihiro Kaneko, Department of Geophysics, Kyoto University, Kyoto, Japan
Carl Tape, Geophysical Institute, University of Alaska Fairbanks, Fairbanks, AK, USA
Ryan Modrak, Los Alamos National Laboratory, Los Alamos, NM, USA
Nick Mortimer, GNS Science, Dunedin, New Zealand
Stephen Bannister, GNS Science, Lower Hutt, New Zealand
John Townend, Victoria University of Wellington, Wellington, New Zealand
|Contact||Bryant Chow (email@example.com)|
|Reference Model||NZ-Wide2.2 Velocity Model (Eberhart-Phillips et al.) Note: The provided reference model has been rotated and interpolated from its original format for use in our tomographic inversion. Additionally, this reference model encompasses a domain that is larger than the velocity model, but its values are only valid within the volume defined by the NZ ATOM North velocity model, stated explicitly in the Area section below.|
|Usage Notes||The geodetic datum of the original model is EPSG:32760 WGS 84/ UTM zone 60S. Two-dimensional latitude, longitude, coordinate variables in the netCDF 4 CLASSIC files for this model are expressed as a function of the UTM X and Y axis (see netCDF CF Metadata Conventions).|
|Data Files Description||The velocity model is separated into three files covering overlapping depth ranges and with differing grid spacing:
|Model Download||Please see the above Data Files Description and Usage Notes sections about these files.
Model files in netCDF 4 Classic format:
|Depth Coverage||-3.0 to 400.0 km (below earth surface)|
|Area||North Island of New Zealand and the Hikurangi subduction zone Coordinate system: UTM 60S x-axis 17000,635000, y-axis 5286000, 5905000 Coordinate system: WGS84 latitude -42.5°, -37.0°, longitude 173.0°, 178.5°|
|Data Set Description||Dataset includes seismic waveforms filtered at 4-30s period. Waveforms from 60 earthquakes recorded on up to 88 broadboad three-component seisimic stations, resulting in 1800 unique source-receiver pairs. Broadband stations include the following networks:|
To cite the original work behind this Earth model:
- Chow, Bryant, Yoshihiro Kaneko, Carl Tape, Ryan Modrak, Nick Mortimer, Stephen Bannister, and John Townend. “Strong upper-plate heterogeneity at the Hikurangi subduction margin (North Island, New Zealand) imaged by adjoint tomography.” Journal of Geophysical Research: Solid Earth, accepted Dec. 9, 2021, https://doi.org/10.1029/2021JB022865
To cite IRIS DMC Data Products effort:
- Trabant, C., A. R. Hutko, M. Bahavar, R. Karstens, T. Ahern, and R. Aster (2012), Data Products at the IRIS DMC: Stepping Stones for Research and Other Applications, Seismological Research Letters, 83(5), 846–854, https://doi.org/10.1785/0220120032.
DOI for this EMC webpage: https://doi.org/10.17611/dp/emc.2021.nzatomnnorthvpvs.1
- Chow, Bryant, Yoshihiro Kaneko, and John Townend. “Evidence for deeply-subducted lower-plate seamounts at the Hikurangi subduction margin: implications for seismic and aseismic behavior.” Journal of Geophysical Research: Solid Earth, accepted Dec. 28, 2021, https://doi.org/10.1029/2021JB022866
- Chow, Bryant, Yoshihiro Kaneko, Carl Tape, Ryan Modrak, and John Townend. “An automated workflow for adjoint tomography—waveform misfits and synthetic inversions for the North Island, New Zealand.” Geophysical Journal International 223, no. 3 (2020): 1461-1480. https://doi.org/10.1093/gji/ggaa381
- Eberhart-Phillips, Donna, Bannister, Stephen, Reyners, Martin, & Henrys, Stuart. (2020). New Zealand Wide model 2.2 seismic velocity and Qs and Qp models for New Zealand [Data set]. Zenodo. https://doi.org/10.5281/zenodo.3779523
- Charles A. Williams, Donna Eberhart‐Phillips, Stephen Bannister, Daniel H. N. Barker, Stuart Henrys, Martin Reyners, Rupert Sutherland; Revised Interface Geometry for the Hikurangi Subduction Zone, New Zealand. Seismological Research Letters 2013; 84 (6): 1066–1073. https://doi.org/10.1785/0220130035
- Model provided by Bryant Chow
revision r0.0: uploaded December 17, 2021.