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Images for square; more images...

Images, eqnz.chch.2010

The former Government Life building in Christchurch's Cathedral Square will be demolished. On my walk around the city May 21, 2014 Christchurch New Zealand. www.stuff.co.nz/the-press/news/christch...

Images, UC QuakeStudies

Looking south west across Cathedral Square showing the eastern side of Christchurch Cathedral (left), the Godley statue (centre left) with the (from left to right) Chief Post Office, the Regent Theatre Building (directly behind the statue on the corner of Worcester Street), the AMP Building, the Government Life Building and the Grand Theatre.

Images, eqnz.chch.2010

Working at getting things out of the Victoria Square before it is demolished. www.stuff.co.nz/the-press/news/christchurch-earthquake-20... What I found on my walk around the city January 15, 2014 Ch...

Images, eqnz.chch.2010

After my visit at the hospital for physiotherapy on my hand I took a walk around the city on my way home. Demolition of the Victoria Square apartments February 12, 2014 Christchurch New Zealand. www.s...

Research papers, University of Canterbury Library

In this paper we apply Full waveform tomography (FWT) based on the Adjoint-Wavefield (AW) method to iteratively invert a 3-D geophysical velocity model for the Canterbury region (Lee, 2017) from a simple initial model. The seismic wavefields was generated using numerical solution of the 3-D elastodynamic/ visco- elastodynamic equations (EMOD3D was adopted (Graves, 1996)), and through the AW method, gradients of model parameters (compression and shear wave velocity) were computed by implementing the cross-adjoint of forward and backward wavefields. The reversed-in-time displacement residual was utilized as the adjoint source. For inversion, we also account for the near source/ station effects, gradient precondition, smoothening (Gaussian filter in spatial domain) and optimal step length. Simulation-to-observation misfit measurements based on 191 sources at 78 seismic stations in the Canterbury region (Figure 1) were used into our inversion. The inversion process includes multiple frequency bands, starting from 0-0.05Hz, and advancing to higher frequency bands (0-0.1Hz and 0-0.2Hz). Each frequency band was used for up to 10 iterations or no optimal step length found. After 3 FWT inversion runs, the simulated seismograms computed using our final model show a good matching with the observed seismograms at frequencies from 0 - 0.2 Hz and the normalized least-squared misfit error has been significantly reduced. Over all, the synthetic study of FWT shows a good application to improve the crustal velocity models from the existed geological models and the seismic data of the different earthquake events happened in the Canterbury region.