A yellow sticker on the door of a house in Worcester Street reading, "Restricted use. No entry except on essential business. Warning: This building has been damaged and its structural safety is questionable. Earthquake aftershocks present danger. Enter only at own risk. Subsequent events may result in increased damage and danger, changing this assessment. Reinspection may be required. The damage is as described below: partial collapse of longitudinal walls". Following on from this are the specific conditions that must be complied with to enable entry into the property, the inspector's identification details, and the date and time the building was inspected. At the bottom the form reads, "Do not remove this placard. Placed by order of the territorial authority Christchurch City Council".
A copy of a document from Empowered Christchurch which was sent to Queen Elizabeth. The document consists of a letter from Empowered Christchurch to Douglas Martin, Crown Manager from the Christchurch City Council, and Official Information Act requests sent to Building and Construction Minister Maurice Williamson and Canterbury Earthquake Recovery Minister Gerry Brownlee. It also includes an appeal to the Queen on behalf of Christchurch residents with badly-damaged houses. Please note that a letter from the Ministry of Business, Innovation and Employment, which was originally included in the document, has been removed due to copyright issues.
After the Christchurch earthquakes, the government declared about 8000 houses as Red Zoned, prohibiting further developments in these properties, and offering the owners to buy them out. The government provided two options for owners: the first was full payment for both land and dwelling at the 2007 property evaluation, the second was payment for land, and the rest to be paid by the owner’s insurance. Most people chose the second option. Using data from LINZ combined with data from StatNZ, this project empirically investigates what led people to choose this second option, and what were the implications of these choices for the owners’ wealth and income.
This poster discusses several possible approaches by which the nonlinear response of surficial soils can be explicitly modelled in physics-based ground motion simulations, focusing on the relative advantages and limitations of the various methodologies. These methods include fully-coupled 3D simulation models that directly allow soil nonlinearity in surficial soils, the domain reduction method for decomposing the physical domain into multiple subdomains for separate simulation, conventional site response analysis uncoupled from the simulations, and finally, the use of simple empirically based site amplification factors We provide the methodology for an ongoing study to explicitly incorporate soil nonlinearity into hybrid broadband simulations of the 2010-2011 Canterbury, New Zealand earthquakes.
In the last two decades, the retail sector has experienced unprecedented upheaval, having severe implications for economic development and sustenance of traditional inner-city retail districts. In the city of Christchurch, New Zealand, this effect has been exacerbated by a series of earthquakes in 2010/2011 which destroyed much of the traditional retail precinct of the city. After extensive rebuild activity of the city’s infrastructure, the momentum of retailers returning to the inner city was initially sluggish but eventually gathered speed supported by increased international visitation. In early 2020, the return to retail normality came to an abrupt halt after the emergence of the COVID-19 pandemic. This study uses spending and transaction data to analyze the compounding impact of the earthquake’s aftermath, shift to online shopping, and the retail disruption in the Christchurch central retail precinct because of COVID-19. The findings illustrate how consumers through their spending respond to different types of external shocks, altering their consumption patterns and retail mode (offline and online) to cope with an ever-changing retail landscape. Each event triggers different spending patterns that have some similarities but also stark differences, having implications for a sustainable and resilient retail industry in Christchurch. Implications for urban retail precinct development are also discussed.
We present initial results from a set of three-dimensional (3D) deterministic earthquake ground motion simulations for the northern Canterbury plains, Christchurch and the Banks Peninsula region, which explicitly incorporate the effects of the surface topography. The simu-lations are done using Hercules, an octree-based finite-element parallel software for solving 3D seismic wave propagation problems in heterogeneous media under kinematic faulting. We describe the efforts undertaken to couple Hercules with the South Island Velocity Model (SIVM), which included changes to the SIVM code in order to allow for single repetitive que-ries and thus achieve a seamless finite-element meshing process within the end-to-end ap-proach adopted in Hercules. We present our selection of the region of interest, which corre-sponds to an area of about 120 km × 120 km, with the 3D model reaching a depth of 60 km. Initial simulation parameters are set for relatively high minimum shear wave velocity and a low maximum frequency, which we are progressively scaling up as computing resources permit. While the effects of topography are typically more important at higher frequencies and low seismic velocities, even at this initial stage of our efforts (with a maximum of 2 Hz and a mini-mum of 500 m/s), it is possible to observe the importance of the topography in the response of some key locations within our model. To highlight these effects we compare the results of the 3D topographic model with respect to those of a flat (squashed) 3D model. We draw rele-vant conclusions from the study of topographic effects during earthquakes for this region and describe our plans for future work.
Paul Nicholls from the University of Canterbury's E-Learning team and Digital Media Group Manager Wayne Riggall in their temporary office in KB02 in Kirkwood Village, the complex of prefabs set up after the earthquakes to provide temporary office and classroom space for the university. The photographer comments, "The e-learning group and the video conferencing team are now located in the Kirkwood Village at the University of Canterbury. It's a very impressive project, about 60 buildings arranged in various configurations with some used for teaching or computer labs, and others as staff offices. We will probably stay here for several years now. Adjoining our area is a space for Wayne, the Digital Media Group Manager, who will organise a sitting area for visitors and small meetings. Beyond Wayne is a closed-off meeting room".
Members of the University of Canterbury's Digital Media Group in their temporary office in KB02 in Kirkwood Village, the complex of prefabs set up after the earthquakes to provide temporary office and classroom space for the university. The photographer comments, "The e-learning group and the video conferencing team are now located in the Kirkwood Village at the University of Canterbury. It's a very impressive project, about 60 buildings arranged in various configurations with some used for teaching or computer labs, and others as staff offices. We will probably stay here for several years now. Looking up the centre of the room towards the front doors. The video conferencing team and Nikki Saunders, the course reader publisher, sit here. (The pizzas are for a moving-in celebration held just after I took these photos.)
A photograph of the back page of a Christchurch City Council form. The form allowed contractors to apply for the authorisation to enter the Christchurch Red Zone after the 22 February 2011 earthquake. Information on the back reads, "What does this authorisation mean for me? I am wearing appropriate personal protection clothing and equipment. At all times DO NOT enter any red placarded building. You may enter a yellow placarded building for a period of time (no longer than 30 minutes) and follow the instruction of the escorts. A green placarded building may be accessed for longer periods. Please note: do not enter any buildings which are not for the purpose of your authorisation".
Paul Nicholls, a member of the University of Canterbury's E-Learning team, in their temporary office in KB02 in Kirkwood Village, the complex of prefabs set up after the earthquakes to provide temporary office and classroom space for the university. The photographer comments, "The e-learning group and the video conferencing team are now located in the Kirkwood Village at the University of Canterbury. It's a very impressive project, about 60 buildings arranged in various configurations with some used for teaching or computer labs, and others as staff offices. We will probably stay here for several years now. Closer view of our corner of the building. We will have some cubicle partitions soon, but I don't know how we'll configure the space then. It's quite nice being so open, but it may be too noisy".
Paul Nicholls, a member of the University of Canterbury's E-Learning team, in their temporary office in KB02 in Kirkwood Village, the complex of prefabs set up after the earthquakes to provide temporary office and classroom space for the university. The photographer comments, "The e-learning group and the video conferencing team are now located in the Kirkwood Village at the University of Canterbury. It's a very impressive project, about 60 buildings arranged in various configurations with some used for teaching or computer labs, and others as staff offices. We will probably stay here for several years now. Our "techy corner", with Paul waiting for the desk-assembler to come back and put his desk together. My desk is in the corner, and Jess is on the right of the window".
Numerous rockfalls released during the 2010–2011 Canterbury earthquake sequence affected vital road sections for local commuters. We quantified rockfall fatality risk on two main routes by adapting a risk approach for roads originally developed for snow avalanche risk. We present results of the collective and individual fatality risks for traffic flow and waiting traffic. Waiting traffic scenarios particularly address the critical spatial-temporal dynamics of risk, which should be acknowledged in operational risk management. Comparing our results with other risks commonly experienced in New Zealand indicates that local rockfall risk is close to tolerability thresholds and likely exceeds acceptable risk.
We present the initial findings from a study of adaptive resilience of lifelines organisations providing essential infrastructure services, in Christchurch, New Zealand following the earthquakes of 2010-2011. Qualitative empirical data was collected from 200 individuals in 11 organisations. Analysis using a grounded theory method identified four major factors that aid organisational response, recovery and renewal following major disruptive events. Our data suggest that quality of top and middle-level leadership, quality of external linkages, level of internal collaboration, ability to learn from experience, and staff well-being and engagement influence adaptive resilience. Our data also suggest that adaptive resilience is a process or capacity, not an outcome and that it is contextual. Post-disaster capacity/resources and post-disaster environment influence the nature of adaptive resilience.
Disasters are rare events with major consequences; yet comparatively little is known about managing employee needs in disaster situations. Based on case studies of four organisations following the devastating earthquakes of 2010 - 2011 in Christchurch, New Zealand, this paper presents a framework using redefined notions of employee needs and expectations, and charting the ways in which these influence organisational recovery and performance. Analysis of in-depth interview data from 47 respondents in four organisations highlighted the evolving nature of employee needs and the crucial role of middle management leadership in mitigating the effects of disasters. The findings have counterintuitive implications for human resource functions in a disaster, suggesting that organisational justice forms a central framework for managing organisational responses to support and engage employees for promoting business recovery.
In 2010 and 2011 a series of earthquakes hit the central region of Canterbury, New Zealand, triggering widespread and damaging liquefaction in the area of Christchurch. Liquefaction occurred in natural clean sand deposits, but also in silty (fines-containing) sand deposits of fluvial origin. Comprehensive research efforts have been subsequently undertaken to identify key factors that influenced liquefaction triggering and severity of its manifestation. This research aims at evaluating the effects of fines content, fabric and layered structure on the cyclic undrained response of silty soils from Christchurch using Direct Simple Shear (DSS) tests. This poster outlines preliminary calibration and verification DSS tests performed on a clean sand to ensure reliability of testing procedures before these are applied to Christchurch soils.
Results from a series of 1D seismic effective stress analyses of natural soil deposits from Christchurch are summarized. The analysed soil columns include sites whose performance during the 2010-2011 Canterbury earthquakes varied significantly, from no liquefaction manifestation at the ground surface to very severe liquefaction, in which case a large area of the site was covered by thick soil ejecta. Key soil profile characteristics and response mechanisms affecting the severity of surface liquefaction manifestation and subsequent damage are explored. The influence of shaking intensity on the triggering and contribution of these mechanisms is also discussed. Careful examination of the results highlights the importance of considering the deposit as a whole, i.e. a system of layers, including interactions between layers in the dynamic response and through pore water pressure redistribution and water flow.
Existing unreinforced masonry (URM) buildings are often composed of traditional construction techniques, with poor connections between walls and diaphragms that results in poor performance when subjected to seismic actions. In these cases the application of the common equivalent static procedure is not applicable because it is not possible to assure “box like” behaviour of the structure. In such conditions the ultimate strength of the structure relies on the behaviour of the macro-elements that compose the deformation mechanisms of the whole structure. These macroelements are a single or combination of structural elements of the structure which are bonded one to each other. The Canterbury earthquake sequence was taken as a reference to estimate the most commonly occurring collapse mechanisms found in New Zealand URM buildings in order to define the most appropriate macroelements.
The full scale, in-situ investigations of instrumented buildings present an excellent opportunity to observe their dynamic response in as-built environment, which includes all the real physical properties of a structure under study and its surroundings. The recorded responses can be used for better understanding of behavior of structures by extracting their dynamic characteristics. It is significantly valuable to examine the behavior of buildings under different excitation scenarios. The trends in dynamic characteristics, such as modal frequencies and damping ratios, thus developed can provide quantitative data for the variations in the behavior of buildings. Moreover, such studies provide invaluable information for the development and calibration of realistic models for the prediction of seismic response of structures in model updating and structural health monitoring studies. This thesis comprises two parts. The first part presents an evaluation of seismic responses of two instrumented three storey RC buildings under a selection of 50 earthquakes and behavioral changes after Ms=7.1 Darfield (2010) and Ms=6.3 Christchurch (2011) earthquakes for an instrumented eight story RC building. The dynamic characteristics of the instrumented buildings were identified using state-of-the-art N4SID system identification technique. Seismic response trends were developed for the three storey instrumented buildings in light of the identified frequencies and the peak response accelerations (PRA). Frequencies were observed to decrease with excitation level while no trends are discernible for the damping ratios. Soil-structure interaction (SSI) effects were also determined to ascertain their contribution in the seismic response. For the eight storey building, it was found through system identification that strong nonlinearities in the structural response occurred and manifested themselves in all identified natural frequencies of the building that exhibited a marked decrease during the strong motion duration compared to the pre-Darfield earthquakes. Evidence of foundation rocking was also found that led to a slight decrease in the identified modal frequencies. Permanent stiffness loss was also observed after the strong motion events. The second part constitutes developing and calibrating finite element model (FEM) of the instrumented three storey RC building with a shear core. A three dimensional FEM of the building is developed in stages to analyze the effect of structural, non-structural components (NSCs) and SSI on the building dynamics. Further to accurately replicate the response of the building following the response trends developed in the first part of the thesis, sensitivity based model updating technique was applied. The FEMs were calibrated by tuning the updating parameters which are stiffnesses of concrete, NSCs and soil. The updating parameters were found to generally follow decreasing trends with the excitation level. Finally, the updated FEM was used in time history analyses to assess the building seismic performance at the serviceability limit state shaking. Overall, this research will contribute towards better understanding and prediction of the behavior of structures subjected to ground motion.
This poster presents work to date on ground motion simulation validation and inversion for the Canterbury, New Zealand region. Recent developments have focused on the collection of different earthquake sources and the verification of the SPECFEM3D software package in forward and inverse simulations. SPECFEM3D is an open source software package which simulates seismic wave propagation and performs adjoint tomography based upon the spectral-element method. Figure 2: Fence diagrams of shear wave velocities highlighting the salient features of the (a) 1D Canterbury velocity model, and (b) 3D Canterbury velocity model. Figure 5: Seismic sources and strong motion stations in the South Island of New Zealand, and corresponding ray paths of observed ground motions. Figure 3: Domain used for the 19th October 2010 Mw 4.8 case study event including the location of the seismic source and strong motion stations. By understanding the predictive and inversion capabilities of SPECFEM3D, the current 3D Canterbury Velocity Model can be iteratively improved to better predict the observed ground motions. This is achieved by minimizing the misfit between observed and simulated ground motions using the built-in optimization algorithm. Figure 1 shows the Canterbury Velocity Model domain considered including the locations of small-to-moderate Mw events [3-4.5], strong motion stations, and ray paths of observed ground motions. The area covered by the ray paths essentially indicates the area of the model which will be most affected by the waveform inversion. The seismic sources used in the ground motion simulations are centroid moment tensor solutions obtained from GeoNet. All earthquake ruptures are modelled as point sources with a Gaussian source time function. The minimum Mw limit is enforced to ensure good signal-to-noise ratio and well constrained source parameters. The maximum Mw limit is enforced to ensure the point source approximation is valid and to minimize off-fault nonlinear effects.
A photograph of a sign taped to a window. The sign includes a bullet pointed list of humorous observations about Christchurch following the February 2011 earthquake. The sign reads, "You know you're from Christchurch when: you use the term 'liquefaction' and 'seismic design' in casual conversation; digging a hole and shitting in your garden is no longer weird; your mayor describes the city as munted. If he means FUBARed, you agree; weaving through car size potholes on the street is no longer weird; a shower is heaven; you have a preference of which kind of silt you'd rather shovel, dry or wet; you see tanks...driving around town; you are always noting what you are under; due to frequent aftershocks during the night, you sleep like a baby - every 10 minutes you wake up and shit yourself".
This is a joint Resilience Framework undertaken by the Electrical, Computer and Software Engineering Department of the University of Auckland in association with West Power and Orion networks and partially funded by the New Zealand National Science Challenge and QuakeCoRE. The Energy- Communication research group nearly accomplished two different researches focusing on both asset resilience and system resilience. Asset resilience research which covers underground cables system in Christchurch region is entitled “2010-2011 Canterbury Earthquake Sequence Impact on 11KV Underground Cables” and system resilience research which covers electricity distribution and communication system in West Coast region is entitled “NZ Electricity Distribution Network Resilience Assessment and Restoration Models following Major Natural Disturbance“. As the fourth milestone of the aforementioned research project, the latest outcome of both projects has been socialised with the stakeholders during the Cigre NZ 2019 Forum.
As damage and loss caused by natural hazards have increased worldwide over the past several decades, it is important for governments and aid agencies to have tools that enable effective post-disaster livelihood recovery to create self-sufficiency for the affected population. This study introduces a framework of critical components that constitute livelihood recovery and the critical factors that lead to people’s livelihood recovery. A comparative case study is employed in this research, combined with questionnaire surveys and interviews with those communities affected by large earthquakes in Lushan, China and in Christchurch and Kaikōura, New Zealand. In Lushan, China, a framework with four livelihood components was established, namely, housing, employment, wellbeing and external assistance. Respondents considered recovery of their housing to be the most essential element for livelihood diversification. External assistance was also rated highly in assisting with their livelihood recovery. Family ties and social connections seemed to have played a larger role than that of government agencies and NGOs. However, the recovery of livelihood cannot be fully achieved without wellbeing aspects being taken into account, and people believed that quality of life and their physical and mental health were essential for livelihood restoration. In Christchurch, New Zealand, the identified livelihood components were validated through in-depth interviews. The results showed that the above framework presenting what constitutes successful livelihood recovery could also be applied in Christchurch. This study also identified the critical factors to affect livelihood recovery following the Lushan and Kaikōura earthquakes, and these include community safety, availability of family support, level of community cohesion, long-term livelihood support, external housing recovery support, level of housing recovery and availability of health and wellbeing support. The framework developed will provide guidance for policy makers and aid agencies to prioritise their strategies and initiatives in assisting people to reinstate their livelihood in a timely manner post-disaster. It will also assist the policy makers and practitioners in China and New Zealand by setting an agenda for preparing for livelihood recovery in non-urgent times so the economic impact and livelihood disruption of those affected can be effectively mitigated.
The increase in urban population has required cities to rethink their strategies for minimising greenhouse gas impacts and adapting to climate change. While urban design and planning policy have been guided by principles such as walkability (to reduce the dependence on cars) and green infrastructure (to enhance the quality of open spaces to support conservation and human values), there have been conflicting views on what spatial strategies will best prepare cities for a challenging future. Researchers supporting compact cities based upon public Transit Oriented Development have claimed that walkability, higher density and mixed-uses make cities more sustainable (Owen, 2009) and that, while green spaces in cities are necessary, they are dull in comparison with shopfronts and street vendors (Speck, 2012, p 250). Other researchers claim that green infrastructure is fundamental to improving urban sustainability and attracting public space users with improved urban comfort, consequently encouraging walkability (Pitman and Ely, 2013). Landscape architects tend to assume that ‘the greener the better’; however, the efficiency of urban greenery in relation to urban comfort and urbanity depends on its density, distribution and the services provided. Green infrastructure can take many forms (from urban forests to street trees) and provide varied services (amended microclimate, aesthetics, ecology and so forth). In this paper, we evaluate the relevance of current policy in Christchurch regarding both best practice in green infrastructure and urban comfort (Tavares, 2015). We focus on the Christchurch Blueprint for rebuilding the central city, and critically examine the post-earthquake paths the city is following regarding its green and grey infrastructures and the resulting urban environment. We discuss the performance and appropriateness of the current Blueprint in post-earthquake Christchurch, particularly as it relates to the challenges that climate change is creating for cities worldwide.
Damage distribution maps from strong earthquakes and recorded data from field experiments have repeatedly shown that the ground surface topography and subsurface stratigraphy play a decisive role in shaping the ground motion characteristics at a site. Published theoretical studies qualitatively agree with observations from past seismic events and experiments; quantitatively, however, they systematically underestimate the absolute level of topographic amplification up to an order of magnitude or more in some cases. We have hypothesized in previous work that this discrepancy stems from idealizations of the geometry, material properties, and incident motion characteristics that most theoretical studies make. In this study, we perform numerical simulations of seismic wave propagation in heterogeneous media with arbitrary ground surface geometry, and compare results with high quality field recordings from a site with strong surface topography. Our goal is to explore whether high-fidelity simulations and realistic numerical models can – contrary to theoretical models – capture quantitatively the frequency and amplitude characteristics of topographic effects. For validation, we use field data from a linear array of nine portable seismometers that we deployed on Mount Pleasant and Heathcote Valley, Christchurch, New Zealand, and we compute empirical standard spectral ratios (SSR) and single-station horizontal-to-vertical spectral ratios (HVSR). The instruments recorded ambient vibrations and remote earthquakes for a period of two months (March-April 2017). We next perform two-dimensional wave propagation simulations using the explicit finite difference code FLAC. We construct our numerical model using a high-resolution (8m) Digital Elevation Map (DEM) available for the site, an estimated subsurface stratigraphy consistent with the geomorphology of the site, and soil properties estimated from in-situ and non-destructive tests. We subject the model to in-plane and out-of-plane incident motions that span a broadband frequency range (0.1-20Hz). Numerical and empirical spectral ratios from our blind prediction are found in very good quantitative agreement for stations on the slope of Mount Pleasant and on the surface of Heathcote Valley, across a wide range of frequencies that reveal the role of topography, soil amplification and basin edge focusing on the distribution of ground surface motion.
A poster created by Empowered Christchurch to advertise their submission to the CERA Draft Transition Recovery Plan on social media.The poster reads, "Submission, CERA Draft Transition Recovery Plan. Risk Acceptance. It is the role of insurance companies, the EQC included, to accept the risks covered under their terms of reference/policies and compensate policyholders when such risks eventuate. However, many policyholders in Christchurch have not been compensated for the damage to their homes and their lives. These responsibilities need to be faced by the entities responsible. An equitable solution needs to be found for properties with hazards such as flooding that are a direct result of the earthquakes. In tandem with this, every effort must be made to protect residents from the risks posed by climate change. We need a city that is driven by the people that live in it, and enabled by a bureaucracy that accepts and mitigates risks, rather than transferring them to the most vulnerable residents".
essential systems upon which the well-being and functioning of societies depend. They deliver a service or a good to the population using a network, a combination of spatially-distributed links and nodes. As they are interconnected, network elements’ functionality is also interdependent. In case of a failure of one component, many others could be momentarily brought out-of-service. Further problems arise for buried infrastructure when it comes to buried infrastructure in earthquake and liquefaction-prone areas for the following reasons: • Technically more demanding inspections than those required for surface horizontal infrastructure • Infrastructure subject to both permanent ground displacement and transient ground deformation • Increase in network maintenance costs (i.e. deterioration due to ageing material and seismic hazard) These challenges suggest careful studies on network resilience will yield significant benefits. For these reasons, the potable water network of Christchurch city (Figure 1) has been selected for its well-characterized topology and its extensive repair dataset.
Hybrid broadband simulation methods typically compute high-frequency portion of ground-motions using a simplified-physics approach (commonly known as “stochastic method”) using the same 1D velocity profile, anelastic attenuation profile and site-attenuation (κ0) value for all sites. However, these parameters relating to Earth structure are known to vary spatially. In this study we modify this conventional approach for high-frequency ground-shaking by using site-specific input parameters (referred to as “site-specific”) and analyze improvements over using same parameters for all sites (referred to as “generic”). First, we theoretically understand how different 1D velocity profiles, anelastic attenuation profiles and site-attenuation (κ0) values affects the Fourier Acceleration Spectrum (FAS). Then, we apply site-specific method to simulate 10 events from the 2010-2011 Canterbury earthquake sequence to assess performance against the generic approach in predicting recorded ground-motions. Our initial results suggest that the site-specific method yields a lower simulation standard deviation than generic case.
This report contributes to a collaborative project between the Marlborough District Council (MDC) and University of Canterbury (UC) which aims to help protect and promote the recovery of native dune systems on the Marlborough coast. It is centred around the mapping of dune vegetation and identification of dune protection zones for old-growth seed sources of the native sand-binders spinifex (Spinifex sericeus) and pīngao (Ficinia spiralis). Both are key habitat-formers associated with nationally threatened dune ecosystems, and pīngao is an important weaving resource and Ngāi Tahu taonga species. The primary goal is to protect existing seed sources that are vital for natural regeneration following major disturbances such as the earthquake event. Several additional protection zones are also identified for areas where new dunes are successfully regenerating, including areas being actively restored in the Beach Aid project that is assisting new native dunes to become established where there is available space.
A city’s planted trees, the great majority of which are in private gardens, play a fundamental role in shaping a city’s wild ecology, ecosystem functioning, and ecosystem services. However, studying tree diversity across a city’s many thousands of separate private gardens is logistically challenging. After the disastrous 2010–2011 earthquakes in Christchurch, New Zealand, over 7,000 homes were abandoned and a botanical survey of these gardens was contracted by the Government’s Canterbury Earthquake Recovery Authority (CERA) prior to buildings being demolished. This unprecedented access to private gardens across the 443.9 hectares ‘Residential Red Zone’ area of eastern Christchurch is a unique opportunity to explore the composition of trees in private gardens across a large area of a New Zealand city. We analysed these survey data to describe the effects of housing age, socio-economics, human population density, and general soil quality, on tree abundance, species richness, and the proportion of indigenous and exotic species. We found that while most of the tree species were exotic, about half of the individual trees were local native species. There is an increasing realisation of the native tree species values among Christchurch citizens and gardens in more recent areas of housing had a higher proportion of smaller/younger native trees. However, the same sites had proportionately more exotic trees, by species and individuals, amongst their larger planted trees than older areas of housing. The majority of the species, and individuals, of the larger (≥10 cm DBH) trees planted in gardens still tend to be exotic species. In newer suburbs, gardens in wealthy areas had more native trees than gardens from poorer areas, while in older suburbs, poorer areas had more native big trees than wealthy areas. In combination, these describe, in detail unparalleled for at least in New Zealand, how the tree infrastructure of the city varies in space and time. This lays the groundwork for better understanding of how wildlife distribution and abundance, wild plant regeneration, and ecosystem services, are affected by the city’s trees.
This article is a critical commentary of how political documentary embodies the traits and functions of alternative journalism. I explore this notion through Obrero (‘worker’) my independent documentary project about the labour migration of Filipino workers to Christchurch, Aotearoa New Zealand, after the earthquake in 2011. This article maps out the points at where the theories and practices of alternative media and documentary intersect. Analysing political documentary as a format of alternative journalism has links to the long tradition of film and video production as a tool for social critique. As a form of practice-based research, Obrero falls under the rubric of alternative journalism—able to represent the politically marginal sectors of the polity and report on issues underreported in the mainstream press. This article concludes that a distribution plan that is responsive to fragmenting audiences works best when alternative journalism no longer targets a niche but transborder audiences.