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Videos, UC QuakeStudies

A video of a panel discussion at the 2014 Seismics and the City forum. The theme of this section was Building Momentum, and it addressed panellists' views on the progress of the rebuild, the main obstacles, and how they can be resolved. The panellists are as follows: Christchurch Mayor Lianne Dalziel; Waimakariri Mayor David Ayers; Roger Sutton, CEO of CERA; Ian Simpson, CEO of the NZ Earthquake Commission; Peter Townsend, CEO of Canterbury Employers' Chamber of Commerce; and Joanna Norris, Editor of The Press.

Research papers, University of Canterbury Library

An as-built reinforced concrete (RC) frame building designed and constructed according to pre-1970s code design construction practice has been recently tested on the shake table at the University of Canterbury. The specimen, 1/2.5 scaled version of the original prototype, consists of two 3-storey 2-bay asymmetric frames in parallel, one interior and one exterior, jointed together by transverse beams and floor slabs. Following the benchmark test, a retrofit intervention has been proposed to rehabilitate the tested specimen. In this paper, detailed information on the assessment and design of the seismic retrofit procedure using GFRP (glass fibre reinforced polymer) materials is given for the whole frame. Hierarchy of strength and sequence of events (damage mechanisms) in the panel zone region are evaluated using a moment-axial load (M-N) interaction performance domain, according to a performance-based retrofit philosophy. Specific limit states or design objectives are targeted with attention given to both strength and deformation limits. In addition, an innovative retrofit solution using FRP anchor dowels for the corner beam-column joints with slabs is proposed. Finally, in order to provide a practical tool for engineering practice, the retrofit procedure is provided in a step-by step flowchart fashion.

Research papers, University of Canterbury Library

This dissertation addresses a diverse range of topics in the physics-based broadband ground motion simulation, with a focus on New Zealand applications. In particular the following topics are addressed: the methodology and computational implementation of a New Zealand Velocity Model for broadband ground motion simulation; generalised parametric functions and spatial correlations for seismic velocities in the Canterbury, New Zealand region from surface-wave-based site characterisation; and ground motion simulations of Hope Fault earthquakes. The paragraphs below outline each contribution in more detail. A necessary component in physics-based ground motion simulation is a 3D model which details the seismic velocities in the region of interest. Here a velocity model construction methodology, its computational implementation, and application in the construction of a New Zealand velocity model for use in physics-based broadband ground motion simulation are presented. The methodology utilises multiple datasets spanning different length scales, which is enabled via the use of modular sub-regions, 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 re- fined velocity parameterizations as they become available. The model comprises explicit representations of the Canterbury, Wellington, Nelson-Tasman, Kaikoura, Marlborough, Waiau, Hanmer and Cheviot sedimentary basins embedded within a regional travel-time tomography-based velocity model for the shallow crust and provides the means to conduct ground motion simulations throughout New Zealand for the first time. Recently developed deep shear-wave velocity profiles in Canterbury enabled models that better characterise the velocity structure within geologic layers of the Canterbury sedimentary basin to be developed. Here the development of depth- and Vs30-dependent para-metric velocity and spatial correlation models to characterise shear-wave velocities within the geologic layers of the Canterbury sedimentary basin are presented. The models utilise data from 22 shear-wave velocity profiles of up to 2.5km 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. Collectively, these models enable seismic velocities to be realistically represented for applications such as 3D ground motion and site response simulations. Lastly the New Zealand velocity model is applied to simulate ground motions for a Mw7.51 rupture of the Hope Fault using a physics-based simulation methodology and a 3D crustal velocity model of New Zealand. The simulation methodology was validated for use in the region through comparison with observations for a suite of historic small magnitude earthquakes located proximal to the Hope Fault. Simulations are compared with conventionally utilised empirical ground motion models, with simulated peak ground velocities being notably higher in regions with modelled sedimentary basins. A sensitivity analysis was undertaken where the source characteristics of magnitude, stress parameter, hypocentre location and kinematic slip distribution were varied and an analysis of their effect on ground motion intensities is presented. It was found that the magnitude and stress parameter strongly influenced long and short period ground motion amplitudes, respectively. Ground motion intensities for the Hope Fault scenario are compared with the 2016 Kaikoura Mw7.8 earthquake, it was found that the Kaikoura earthquake produced stronger motions along the eastern South Island, while the Hope Fault scenario resulted in stronger motions immediately West of the near-fault region. The simulated ground motions for this scenario complement prior empirically-based estimates and are informative for mitigation and emergency planning purposes.

Research papers, University of Canterbury Library

The 2010-2011 Canterbury earthquakes were recorded over a dense strong motion network in the near-source region, yielding significant observational evidence of seismic complexities, and a basis for interpretation of multi-disciplinary datasets and induced damage to the natural and built environment. This paper provides an overview of observed strong motions from these events and retrospective comparisons with both empirical and physics-based ground motion models. Both empirical and physics-based methods provide good predictions of observations at short vibration periods in an average sense. However, observed ground motion amplitudes at specific locations, such as Heathcote Valley, are seen to systematically depart from ‘average’ empirical predictions as a result of near surface stratigraphic and topographic features which are well modelled via sitespecific response analyses. Significant insight into the long period bias in empirical predictions is obtained from the use of hybrid broadband ground motion simulation. The comparison of both empirical and physics-based simulations against a set of 10 events in the sequence clearly illustrates the potential for simulations to improve ground motion and site response prediction, both at present, and further in the future.

Research papers, University of Canterbury Library

This research employs a deterministic seismic risk assessment methodology to assess the potential damage and loss at meshblock level in the Christchurch CBD and Mount Pleasant primarily due to building damage caused by earthquake ground shaking. Expected losses in terms of dollar value and casualties are calculated for two earthquake scenarios. Findings are based on: (1) data describing the earthquake ground shaking and microzonation effects; (2) an inventory of buildings by value, floor area, replacement value, occupancy and age; (3) damage ratios defining the performance of buildings as a function of earthquake intensity; (4) daytime and night-time population distribution data and (5) casualty functions defining casualty risk as a function of building damage. A GIS serves as a platform for collecting, storing and analyzing the original and the derived data. It also allows for easy display of input and output data, providing a critical functionality for communication of outcomes. The results of this study suggest that economic losses due to building damage in the Christchurch CBD and Mount Pleasant will possibly be in the order of $5.6 and $35.3 million in a magnitude 8.0 Alpine fault earthquake and a magnitude 7.0 Ashley fault earthquake respectively. Damage to non-residential buildings constitutes the vast majority of the economic loss. Casualty numbers are expected to be between 0 and 10.

Research Papers, Lincoln University

There is a critical strand of literature suggesting that there are no ‘natural’ disasters (Abramovitz, 2001; Anderson and Woodrow, 1998; Clarke, 2008; Hinchliffe, 2004). There are only those that leave us – the people - more or less shaken and disturbed. There may be some substance to this; for example, how many readers recall the 7.8 magnitude earthquake centred in Fiordland in July 2009? Because it was so far away from a major centre and very few people suffered any consequences, the number is likely to be far fewer than those who remember (all too vividly) the relatively smaller 7.1 magnitude Canterbury quake of September 4th 2010 and the more recent 6.3 magnitude February 22nd 2011 event. One implication of this construction of disasters is that seismic events, like those in Canterbury, are as much socio-political as they are geological. Yet, as this paper shows, the temptation in recovery is to tick boxes and rebuild rather than recover, and to focus on hard infrastructure rather than civic expertise and community involvement. In this paper I draw upon different models of community engagement and use Putnam’s (1995) notion of ‘social capital’ to frame the argument that ‘building bridges’ after a disaster is a complex blend of engineering, communication and collaboration. I then present the results of a qualitative research project undertaken after the September 4th earthquake. This research helps to illustrate the important connections between technical rebuilding, social capital, recovery processes and overall urban resilience.

Images, UC QuakeStudies

HITLab NZ's Andreas Dunser and UC clinical psychologists Dr Janet Carter, Dr Eileen Britt and Associate Professor Martin Dorahy, who are creating an earthquake simulator at the University of Canterbury to investigate ways to help Cantabrians overcome post-traumatic stress disorders caused by ongoing seismic activity.

Images, UC QuakeStudies

HITLab NZ's Andreas Dunser and UC clinical psychologists Dr Janet Carter, Dr Eileen Britt and Associate Professor Martin Dorahy, who are creating an earthquake simulator at the University of Canterbury to investigate ways to help Cantabrians overcome post-traumatic stress disorders caused by ongoing seismic activity.

Images, eqnz.chch.2010

Toppled grain silos on the outskirts of Darfield near the epicentre of the magnitude 7,1 earthquake that struck on Saturday 4 September 2010.

Images, eqnz.chch.2010

Toppled grain silos on the outskirts of Darfield near the epicentre of the magnitude 7,1 earthquake that struck on Saturday 4 September 2010.

Images, eqnz.chch.2010

Damaged rose window of the St John the Baptist Church at Latimer Square; aftermath of the magnitude 7.1 earthquake that struck Christchurch on Saturday 4 September 2010.

Images, eqnz.chch.2010

Toppled grain silos on the outskirts of Darfield near the epicentre of the magnitude 7,1 earthquake that struck on Saturday 4 September 2010.

Images, eqnz.chch.2010

Toppled grain silos on the outskirts of Darfield near the epicentre of the magnitude 7,1 earthquake that struck on Saturday 4 September 2010.

Videos, eqnz.chch.2010

At Greendale Faultline on Highfield Road in mid-Canterbury, where the magnitude 7.1 earthquake on 4 September 2010 originated.

Images, eqnz.chch.2010

Repairs being carried out on this restaurant (converted from a church) at the Hereford Street / Manchester Street intersection;aftermath of the magnitude 7.1 earthquake that struck Christchurch on Saturday 4 September 2010.

Images, eqnz.chch.2010

Heaving and subsidence on the faultline left scars where the magnitude 7.1 earthquake on Saturday 4 September 2010 originated.

Images, eqnz.chch.2010

Toppled grain silos on the outskirts of Darfield near the epicentre of the magnitude 7,1 earthquake that struck on Saturday 4 September 2010.

Images, eqnz.chch.2010

Toppled grain silos on the outskirts of Darfield near the epicentre of the magnitude 7,1 earthquake that struck on Saturday 4 September 2010.

Images, eqnz.chch.2010

Toppled grain silos on the outskirts of Darfield near the epicentre of the magnitude 7,1 earthquake that struck on Saturday 4 September 2010.

Images, eqnz.chch.2010

Toppled grain silos on the outskirts of Darfield near the epicentre of the magnitude 7,1 earthquake that struck on Saturday 4 September 2010.

Images, eqnz.chch.2010

The latest (but temporary) tourist attraction in mid-Canterbury! This was the previously unknown faultline where the Saturday 4 September 2010 earthquake originated.

Videos, eqnz.chch.2010

At Greendale Faultline on Highfield Road in mid-Canterbury, where the magnitude 7.1 earthquake on 4 September 2010 originated.

Videos, eqnz.chch.2010

At Greendale Faultline on Highfield Road in mid-Canterbury, where the magnitude 7.1 earthquake on 4 September 2010 originated.

Images, eqnz.chch.2010

Toppled grain silos on the outskirts of Darfield near the epicentre of the magnitude 7,1 earthquake that struck on Saturday 4 September 2010.

Images, eqnz.chch.2010

Tension cracks at least 300 mm deep, on the previously unknown faultline from which the Saturday 4 September 2010 earthquake originated.

Images, eqnz.chch.2010

This beautiful building on Madras Street is red stickered and may be condemned if the structural damage it suffered in the magnitude 7,1 earthquake on Saturday 4 September 2010 cannot be repaired.

Images, eqnz.chch.2010

Toppled grain silos on the outskirts of Darfield near the epicentre of the magnitude 7,1 earthquake that struck on Saturday 4 September 2010.

Images, eqnz.chch.2010

This beautiful building on Madras Street is red stickered and may be condemned if the structural damage it suffered in the magnitude 7,1 earthquake on Saturday 4 September 2010 cannot be repaired.

Images, eqnz.chch.2010

On the way to Darfield to locate the faultline where the tectonic plates slipped, causing the magnitude 7.1 earthquake on Saturday 4 September 2010.

Images, eqnz.chch.2010

This beautiful building on Madras Street is red stickered and may be condemned if the structural damage it suffered in the magnitude 7,1 earthquake on Saturday 4 September 2010 cannot be repaired.