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Research papers, University of Canterbury Library

The 14 November 2016 Kaikōura earthquake had major impacts on New Zealand's transport system. Road, rail and port infrastructure was damaged, creating substantial disruption for transport operators, residents, tourists, and business owners in the Canterbury, Marlborough and Wellington regions, with knock-on consequences elsewhere. During both the response and recovery phases, a large amount of information and data relating to the transport system was generated, managed, analysed, and exchanged within and between organisations to assist decision making. To improve information and data exchanges and related decision making in the transport sector during future events and guide new resilience strategies, we present key findings from a recent post-earthquake assessment. The research involved 35 different stakeholder groups and was conducted for the Ministry of Transport. We consider what transport information was available, its usefulness, where it was sourced from, mechanisms for data transfer between organisations, and suggested approaches for continued monitoring.

Research papers, University of Canterbury Library

Asset management in power systems is exercised to improve network reliability to provide confidence and security for customers and asset owners. While there are well-established reliability metrics that are used to measure and manage business-as-usual disruptions, an increasing appreciation of the consequences of low-probability high-impact events means that resilience is increasingly being factored into asset management in order to provide robustness and redundancy to components and wider networks. This is particularly important for electricity systems, given that a range of other infrastructure lifelines depend upon their operation. The 2010-2011 Canterbury Earthquake Sequence provides valuable insights into electricity system criticality and resilience in the face of severe earthquake impacts. While above-ground assets are relatively easy to monitor and repair, underground assets such as cables emplaced across wide areas in the distribution network are difficult to monitor, identify faults on, and repair. This study has characterised in detail the impacts to buried electricity cables in Christchurch resulting from seismically-induced ground deformation caused primarily by liquefaction and lateral spread. Primary modes of failure include cable bending, stretching, insulation damage, joint braking and, being pulled off other equipment such as substation connections. Performance and repair data have been compiled into a detailed geospatial database, which in combination with spatial models of peak ground acceleration, peak ground velocity and ground deformation, will be used to establish rigorous relationships between seismicity and performance. These metrics will be used to inform asset owners of network performance in future earthquakes, further assess component criticality, and provide resilience metrics.

Research papers, University of Canterbury Library

A significant portion of economic loss from the Canterbury Earthquake sequence in 2010-2011 was attributed to losses to residential buildings. These accounted for approximately $12B of a total $40B economic losses (Horspool, 2016). While a significant amount of research effort has since been aimed at research in the commercial sector, little has been done to reduce the vulnerability of the residential building stock.

Research papers, University of Canterbury Library

Knowing how to rapidly rebuild disaster-damaged infrastructure, while deciding appropriate recovery strategies and catering for future investment is a matter of core interest to government decision makers, utility providers, and business sectors. The purpose of this research is to explore the effects of decisions and outcomes for physical reconstruction on the overall recovery process of horizontal infrastructure in New Zealand using the Canterbury and Kaikoura earthquakes as cases. A mixed approach including a systematic review, questionnaire survey and semi-structured interviews is used to capture perspectives of those involved in reconstruction process and gain insights into the effect of critical elements on infrastructure downtime. Findings from this research will contribute towards advancements of a systems dynamics model considering critical decision-making variables across phases of the reconstruction process to assess how these variables affect the rebuild process and the corresponding downtime. This project will improve the ability to explore alternative resilience improvement pathways and test the efficacy of alternative means for facilitating a faster and better reconstruction process.

Research papers, University of Canterbury Library

This research investigates the validation of simulated ground motions on complex structural systems. In this study, the seismic responses of two buildings are compared when they are subjected to as-recorded ground motions and simulated ones. The buildings have been designed based on New Zealand codes and physically constructed in Christchurch, New Zealand. The recorded ground motions are selected from 40 stations database of the historical 22 Feb. 2011 Christchurch earthquake. The Graves and Pitarka (2015) methodology is used to generate the simulated ground motions. The geometric mean of maximum inter-story drift and peak floor acceleration are selected as the main seismic responses. Also, the variation of these parameters due to record to record variability are investigated. Moreover, statistical hypothesis testing is used to investigate the similarity of results between observed and simulated ground motions. The results indicate a general agreement between the peak floor acceleration calculated by simulated and recorded ground motions for two buildings. While according to the hypothesis tests result, the difference in drift can be significant for the building with a shorter period. The results will help engineers and researchers to use or revise the procedure by using simulated ground motions for obtaining seismic responses.

Research papers, University of Canterbury Library

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.

Research papers, University of Canterbury Library

We measure the longer-term effect of a major earthquake on the local economy, using night-time light intensity measured from space, and investigate whether insurance claim payments for damaged residential property affected the local recovery process. We focus on the destructive Canterbury Earthquake Sequence (CES) 2010 -2011 as our case study. Uniquely for this event, more than 95% of residential housing units were covered by insurance, but insurance payments were staggered over 5 years, enabling us to identify their local impact. We find that night-time luminosity can capture the process of recovery and describe the recovery’s determinants. We also find that insurance payments contributed significantly to the process of economic recovery after the earthquake, but delayed payments were less affective and cash settlement of claims were more effective than insurance-managed repairs in contributing to local recovery.

Research papers, University of Canterbury Library

Geospatial liquefaction models aim to predict liquefaction using data that is free and readily-available. This data includes (i) common ground-motion intensity measures; and (ii) geospatial parameters (e.g., among many, distance to rivers, distance to coast, and Vs30 estimated from topography) which are used to infer characteristics of the subsurface without in-situ testing. Since their recent inception, such models have been used to predict geohazard impacts throughout New Zealand (e.g., in conjunction with regional ground-motion simulations). While past studies have demonstrated that geospatial liquefaction-models show great promise, the resolution and accuracy of the geospatial data underlying these models is notably poor. As an example, mapped rivers and coastlines often plot hundreds of meters from their actual locations. This stems from the fact that geospatial models aim to rapidly predict liquefaction anywhere in the world and thus utilize the lowest common denominator of available geospatial data, even though higher quality data is often available (e.g., in New Zealand). Accordingly, this study investigates whether the performance of geospatial models can be improved using higher-quality input data. This analysis is performed using (i) 15,101 liquefaction case studies compiled from the 2010-2016 Canterbury Earthquakes; and (ii) geospatial data readily available in New Zealand. In particular, we utilize alternative, higher-quality data to estimate: locations of rivers and streams; location of coastline; depth to ground water; Vs30; and PGV. Most notably, a region-specific Vs30 model improves performance (Figs. 3-4), while other data variants generally have little-to-no effect, even when the “standard” and “high-quality” values differ significantly (Fig. 2). This finding is consistent with the greater sensitivity of geospatial models to Vs30, relative to any other input (Fig. 5), and has implications for modeling in locales worldwide where high quality geospatial data is available.

Research papers, University of Canterbury Library

Earthquake-triggered soil liquefaction caused extensive damage and heavy economic losses in Christchurch during the 2010-2011 Canterbury earthquakes. The most severe manifestations of liquefaction were associated with the presence of natural deposits of clean sands and silty sands of fluvial origin. However, liquefaction resistance of fines-containing sands is commonly inferred from empirical relationships based on clean sands (i.e. sands with less than 5% fines). Hence, existing evaluation methods have poor accuracy when applied to silty sands. Also, existing methods do not quantify appropriately the influence on liquefaction resistance of soil fabric and structure, which are unique to a specific depositional environment. This study looks at the influence of fines content, soil fabric (i.e. arrangement of soil particles) and structure (e.g. layering, segregation) on the undrained cyclic behaviour and liquefaction resistance of fines-containing sandy soils from Christchurch using Direct Simple Shear (DSS) tests on soil specimens reconstituted in the laboratory with the water sedimentation technique. The poster describes experimental procedures and presents early test results on two sands retrieved at two different sites in Christchurch.

Research papers, University of Canterbury Library

Background This study examines the performance of site response analysis via nonlinear total-stress 1D wave-propagation for modelling site effects in physics-based ground motion simulations of the 2010-2011 Canterbury, New Zealand earthquake sequence. This approach allows for explicit modeling of 3D ground motion phenomena at the regional scale, as well as detailed nonlinear site effects at the local scale. The approach is compared to a more commonly used empirical VS30 (30 m time-averaged shear wave velocity)-based method for computing site amplification as proposed by Graves and Pitarka (2010, 2015), and to empirical ground motion prediction via a ground motion model (GMM).

Research papers, University of Canterbury Library

Introduction This poster presents the inferred initial performance and recovery of the water supply network of Christchurch following the 22 February 2011 Mw 6.2 earthquake. Results are presented in a geospatial and temporal fashion. This work strengthens the current understanding of the restoration of such a system after a disaster and quantifies the losses caused by this earthquake in respect with the Christchurch community. Figure 1 presents the topology of the water supply network as well as the spatial distribution of the buildings and their use.

Research papers, University of Canterbury Library

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.

Research papers, University of Canterbury Library

Detailed studies on the sediment budget may reveal valuable insights into the successive build-up of the Canterbury Plains and their modification by Holocene fluvialaction connected to major braided rivers. Additionally, they bear implications beyond these fluvial aspects. Palaeoseismological studies claim to have detected signals of major Alpine Fault earthquakes in coastal environments along the eastern seaboard of the South Island (McFadgen and Goff, 2005). This requires high connectivity between the lower reaches of major braided rivers and their mountain catchments to generate immediate significant sediment pulses. It would be contradictory to the above mentioned hypothesis though. Obtaining better control on sediment budgets of braided rivers like the Waimakariri River will finally add significant value to multiple scientific and applied topics like regional resource management. An essential first step of sediment budget studies Is to systematically map the geomorphology, conventionally in the field and/or using remote-sensing applications, to localise, genetically identify, and classify landforms or entire toposequences of the area being investigated. In formerly glaciated mountain environments it is also indispensable to obtain all available chronological information supporting subsequent investigations.

Research papers, University of Canterbury Library

Welcome to the Recover newsletter Issue 6 from the Marine Ecology Research Group (MERG) of the University of Canterbury. Recover is designed to keep you updated on our MBIE-funded earthquake recovery project called RECOVER (Reef Ecology, Coastal Values & Earthquake Recovery). This 6th instalment features the ‘new land’ created by the earthquake uplift of the coastline, recreational uses of beaches in Marlborough, and pāua survey work and hatchery projects with our partners in Kaikōura.

Research Papers, Lincoln University

Creativity that is driven by a need for physical or economic survival, which disasters are likely to inspire, raises the question of whether such creativity fits with conventional theories and perspectives of creativity. In this paper we use the opportunity afforded by the 2010-2013 Christchurch, New Zealand earthquakes to follow and assess the creative practices and responses of a number of groups and individuals. We use in-depth interviews to tease out motivations and read these against a range of theoretical propositions about creativity. In particular, we focus on the construct of “elite panic” and the degree to which this appeared to be evident in the Christchurch earthquakes context. Bureaucratic attempts to control or limit creativity were present but they did not produce a completely blanket dampening effect. Certain individuals and groups seemed to be pre-equipped to navigate or ignore potential blocks to creativity. We argue, using Geir Kaufmann’s novelty-creativity matrix and aspects of Teresa Amabile’s and Michael G. Pratt’s revised componential theory of creativity that a special form of disaster creativity does exist.

Research Papers, Lincoln University

During the 21st century, New Zealand has experienced increasing public concern over the quality of the design and appearance of new developments, and their effects on the urban environment. In response to this, a number of local authorities developed a range of tools to address this issue, including urban design panels to review proposals and provide independent advice. Following the 2010 and 2011 Canterbury earthquake sequence, the commitment to achieve high quality urban design within Christchurch was given further importance, with the city facing the unprecedented challenge of rebuilding a ‘vibrant and successful city’. The rebuild and regeneration reinforced the need for independent design review, putting more focus and emphasis on the role and use of the urban design panel; first through collaboratively assisting applicants in achieving a better design outcome for their development by providing an independent set of eyes on their design; and secondly in assisting Council officers in forming their recommendations on resource consent decisions. However, there is a perception that urban design and the role of the urban design panel is not fully understood, with some stakeholders arguing that Council’s urban design requirements are adding cost and complexity to their developments. The purpose of this research was to develop a better understanding on the role of the Christchurch urban design panel post-earthquake in the central city; its direct and indirect influence on the built environment; and the deficiencies in the broader planning framework and institutional settings that it might be addressing. Ultimately, the perceived role of the Panel is understood, and there is agreement that urban design is having a positive influence on the built environment, albeit viewed differently amongst the varying groups involved. What has become clear throughout this research is that the perceived tension between the development community and urban design well and truly exists, with the urban design panel contributing towards this. This tension is exacerbated further through the cost of urban design to developers, and the drive for financial return from their investments. The panel, albeit promoting a positive experience, is simply a ‘tick box’ exercise for some, and as the research suggests, groups or professional are determining themselves what constitutes good urban design, based on their attitude, the context in which they sit and the financial constraints to incorporate good design elements. It is perhaps a bleak time for urban design, and more about building homes.

Research Papers, Lincoln University

On 4 September 2010, a 7.1 magnitude earthquake struck near Darfield, 40 kilometres west of Christchurch, New Zealand. The quake caused significant damage to land and buildings nearby, with damage extending to Christchurch city. On 22 February 2011, a 6.3 magnitude earthquake struck Christchurch, causing extensive and significant damage across the city and with the loss of 185 lives. Years on from these events, occasional large aftershocks continue to shake the region. Two main entomological collections were situated within close proximity to the 2010/11 Canterbury earthquakes. The Lincoln University Entomology Research Collection, which is housed on the 5th floor of a 7 storey building, was 27.5 km from the 2010 Darfield earthquake epicentre. The Canterbury Museum Entomology Collection, which is housed in the basement of a multi-storeyed heritage building, was 10 km from the 2011 Christchurch earthquake epicentre. We discuss the impacts of the earthquakes on these collections, the causes of the damage to the specimens and facilities, and subsequent efforts that were made to prevent further damage in the event of future seismic events. We also discuss the wider need for preparedness against the risks posed by natural disasters and other catastrophic events.

Research Papers, Lincoln University

Tree mortality is a fundamental process governing forest dynamics, but understanding tree mortality patterns is challenging because large, long-term datasets are required. Describing size-specific mortality patterns can be especially difficult, due to few trees in larger size classes. We used permanent plot data from Nothofagus solandri var. cliffortioides (mountain beech) forest on the eastern slopes of the Southern Alps, New Zealand, where the fates of trees on 250 plots of 0.04 ha were followed, to examine: (1) patterns of size-specific mortality over three consecutive periods spanning 30 years, each characterised by different disturbance, and (2) the strength and direction of neighbourhood crowding effects on sizespecific mortality rates. We found that the size-specific mortality function was U-shaped over the 30-year period as well as within two shorter periods characterised by small-scale pinhole beetle and windthrow disturbance. During a third period, characterised by earthquake disturbance, tree mortality was less size dependent. Small trees (,20 cm in diameter) were more likely to die, in all three periods, if surrounded by a high basal area of larger neighbours, suggesting that sizeasymmetric competition for light was a major cause of mortality. In contrast, large trees ($20 cm in diameter) were more likely to die in the first period if they had few neighbours, indicating that positive crowding effects were sometimes important for survival of large trees. Overall our results suggest that temporal variability in size-specific mortality patterns, and positive interactions between large trees, may sometimes need to be incorporated into models of forest dynamics.

Research Papers, Lincoln University

Imagined landscapes find their form in utopian dreaming. As ideal places, utopias are set up according to the ideals of their designers. Inevitably, utopias become compromised when they move from the imaginary into the actual. Opportunities to create utopias rely largely on a blank slate, a landscape unimpeded by the inconveniences of existing occupation – or even topography. Christchurch has seen two utopian moments. The first was at the time of European settlement in the mid-nineteenth century, when imported ideals provided a model for a new city. The earthquakes of 2010 and 2011 provided a second point at which utopian dreaming spurred visions for the city. Christchurch’s earthquakes have provided a unique opportunity for a city to re-imagine itself. Yet, as is the fate for all imaginary places, reality got in the way.

Research Papers, Lincoln University

Disasters are often followed by a large-scale stimulus supporting the economy through the built environment, which can last years. During this time, official economic indicators tend to suggest the economy is doing well, but as activity winds down, the sentiment can quickly change. In response to the damaging 2011 earthquakes in Canterbury, New Zealand, the regional economy outpaced national economic growth rates for several years during the rebuild. The repair work on the built environment created years of elevated building activity. However, after the peak of the rebuilding activity, as economic and employment growth retracts below national growth, we are left with the question of how the underlying economy performs during large scale stimulus activity in the built environment. This paper assesses the performance of the underlying economy by quantifying the usual, demand-driven level of building activity at this time. Applying an Input–Output approach and excluding the economic benefit gained from the investment stimulus reveals the performance of the underlying economy. The results reveal a strong growing underlying economy, and while convergence was expected as the stimulus slowed down, the results found that growth had already crossed over for some time. The results reveal that the investment stimulus provides an initial 1.5% to 2% growth buffer from the underlying economy before the growth rates cross over. This supports short-term economic recovery and enables the underlying economy to transition away from a significant rebuild stimulus. Once the growth crosses over, five years after the disaster, economic growth in the underlying economy remains buoyant even if official regional economic data suggest otherwise.

Research Papers, Lincoln University

On 14 November 2016, a magnitude (Mw) 7.8 earthquake struck the small coastal settlement of Kaikōura, Aotearoa-New Zealand. With an economy based on tourism, agriculture, and fishing, Kaikōura was immediately faced with significant logistical, economic, and social challenges caused by damage to critical infrastructure and lifelines, essential to its main industries. Massive landslips cut offroad and rail access, stranding hundreds of tourists, and halting the collection, processing and distribution of agricultural products. At the coast, the seabed rose two metres, limiting harbour-access to high tide, with implications for whale watching tours and commercial fisheries. Throughout the region there was significant damage to homes, businesses, and farmland, leaving owners and residents facing an uncertain future. This paper uses qualitative case study analysis to explore post-quake transformations in a rural context. The aim is to gain insight into the distinctive dynamics of disaster response mechanisms, focusing on two initiatives that have emerged in direct response to the disaster. The first examines the ways in which agriculture, food harvesting, production and distribution are being reimagined with the potential to enhance regional food security. The second examines the rescaling of power in decision-making processes following the disaster, specifically examining the ways in which rural actors are leveraging networks to meet their needs and the consequences of that repositioning on rural (and national) governance arrangements. In these and other ways, the local economy is being revitalised, and regional resilience enhanced through diversification, capitalising not on the disaster but the region's natural, social, and cultural capital. Drawing on insights and experience of local stakeholders, policy- and decision-makers, and community representatives we highlight the diverse ways in which these endeavours are an attempt to create something new, revealing also the barriers which needed to be overcome to reshape local livelihoods. Results reveal that the process of transformation as part of rural recovery must be grounded in the lived reality of local residents and their understanding of place, incorporating and building on regional social, environmental, and economic characteristics. In this, the need to respond rapidly to realise opportunities must be balanced with the community-centric approach, with greater recognition given to the contested nature of the decisions to be made. Insights from the case examples can inform preparedness and recovery planning elsewhere, and provide a rich, real-time example of the ways in which disasters can create opportunities for reimagining resilient futures.

Research Papers, Lincoln University

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.

Research Papers, Lincoln University

Memorial design in the West has been explored in depth (Stevens and Franck, 2016; Williams, 2007), and for landscape architects it presents opportunities and challenges. However, there is little in the English language literature about memorial design in China. How have Chinese designers responded to the commemorative settings of war and disaster? This study will adopt the method of case study to analyse two of the most representative memorials in China: Nanjing Massacre Memorial Hall (war) and Tangshan Earthquake Memorial Hall (disaster). Both landscapes have undergone three or four renovations and extensions in the last four decades, demonstrating the practical effects of the Chinese landscape theory. These examples of responses to trauma through memorial landscape interventions are testimonies to the witnesses, victims, abusers, ordinary people, youth and the place where the tragedy took place. This study will explore the reconstruction and expansion of the two memorials under the background of China's policies on memorial landscapes in different periods, as well as their functions of each stage. The research will examine how existing Chinese memorial theories exhibit unique responses at different times in response to the sadness and needs experienced by different users. Key Words：memorial landscape; memorial language; victims; descriptive; architecture; experence; disaster; memorial hall; landscape development; Chinese memorial; war.

Research Papers, Lincoln University

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.

Research Papers, Lincoln University

Disasters are a critical topic for practitioners of landscape architecture. A fundamental role of the profession is disaster prevention or mitigation through practitioners having a thorough understanding of known threats. Once we reach the ‘other side’ of a disaster – the aftermath – landscape architecture plays a central response in dealing with its consequences, rebuilding of settlements and infrastructure and gaining an enhanced understanding of the causes of any failures. Landscape architecture must respond not only to the physical dimensions of disaster landscapes but also to the social, psychological and spiritual aspects. Landscape’s experiential potency is heightened in disasters in ways that may challenge and extend the spectrum of emotions. Identity is rooted in landscape, and massive transformation through the impact of a disaster can lead to ongoing psychological devastation. Memory and landscape are tightly intertwined as part of individual and collective identities, as connections to place and time. The ruptures caused by disasters present a challenge to remembering the lives lost and the prior condition of the landscape, the intimate attachments to places now gone and even the event itself.

Research Papers, Lincoln University

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.

Research Papers, Lincoln University

The city of Christchurch, New Zealand, incurred significant damage due to a series of earthquakes in 2010 and 2011. The city had, by the late 2010s, regained economic and social normalcy after a sustained period of rebuilding and economic recovery. Through the concerted rebuilding effort, a modern central business district (CBD) with redesigned infrastructure and amenities was developed. The Christchurch rebuild was underpinned by a commitment of urban planners to an open and connected city, including the use of innovative technologies to gather, use and share data. As was the case elsewhere, the COVID-19 pandemic brought about significant disruptions to social and economic life in Christchurch. Border closures, lockdowns, trading limitations and other restrictions on movement led to changes in traditional consumer behaviors and affected the retail sector’s resilience. In this study, we used CBD pedestrian traffic data gathered from various locations to predict changes in retail spending and identify recovery implications through the lens of retail resilience. We found that the COVID-19 pandemic and its related lockdowns have driven a substantive change in the behavioral patterns of city users. The implications for resilient retail, sustainable policy and further research are explored.

Research Papers, Lincoln University

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.

Research Papers, Lincoln University

Orientation: Large-scale events such as disasters, wars and pandemics disrupt the economy by diverging resource allocation, which could alter employment growth within the economy during recovery. Research purpose: The literature on the disaster–economic nexus predominantly considers the aggregate performance of the economy, including the stimulus injection. This research assesses the employment transition following a disaster by removing this stimulus injection and evaluating the economy’s performance during recovery. Motivation for the study: The underlying economy’s performance without the stimulus’ benefit remains primarily unanswered. A single disaster event is used to assess the employment transition to guide future stimulus response for disasters. Research approach/design and method: Canterbury, New Zealand, was affected by a series of earthquakes in 2010–2011 and is used as a single case study. Applying the historical construction–economic relationship, a counterfactual level of economic activity is quantified and compared with official results. Using an input–output model to remove the economy-wide impact from the elevated activity reveals the performance of the underlying economy and employment transition during recovery. Main findings: The results indicate a return to a demand-driven level of building activity 10 years after the disaster. Employment transition is characterised by two distinct periods. The first 5 years are stimulus-driven, while the 5 years that follow are demand-driven from the underlying economy. After the initial period of elevated building activity, construction repositioned to its long-term level near 5% of value add. Practical/managerial implications: The level of building activity could be used to confidently assess the performance of regional economies following a destructive disaster. The study results argue for an incentive to redevelop the affected area as quickly as possible to mitigate the negative effect of the destruction and provide a stimulus for the economy. Contribution/value-add: This study contributes to a growing stream of regional disaster economics research that assesses the economic effect using a single case study.

Research Papers, Lincoln University

Study region: Christchurch, New Zealand. Study focus: Low-lying coastal cities worldwide are vulnerable to shallow groundwater salinization caused by saltwater intrusion and anthropogenic activities. Shallow groundwater salinization can have cascading negative impacts on municipal assets, but this is rarely considered compared to impacts of salinization on water supply. Here, shallow groundwater salinity was sampled at high spatial resolution (1.3 piezometer/km²), then mapped and spatially interpolated. This was possible due to a uniquely extensive set of shallow piezometers installed in response to the 2010–11 Canterbury Earthquake Sequence to assess liquefaction risk. The municipal assets located within the brackish groundwater areas were highlighted. New hydrological insights for the region: Brackish groundwater areas were centred on a spit of coastal sand dunes and inside the meander of a tidal river with poorly drained soils. The municipal assets located within these areas include: (i) wastewater and stormwater pipes constructed from steel-reinforced concrete, which, if damaged, are vulnerable to premature failure when exposed to chloride underwater, and (ii) 41 parks and reserves totalling 236 ha, within which salt-intolerant groundwater-dependent species are at risk. This research highlights the importance of determining areas of saline shallow groundwater in low-lying coastal urban settings and the co-located municipal assets to allow the prioritisation of sites for future monitoring and management.