The magnitude Mw 6.2 earthquake of February 22nd 2011 that struck beneath the city of Christchurch, New Zealand, caused widespread damage and was particularly destructive to the Central Business District (CBD). The shaking caused major damage, including collapses of structures, and initiated ground failure in the form of soil liquefaction and consequent effects such as sand boils, surface flooding, large differential settlements of buildings and lateral spreading of ground towards rivers were observed. A research project underway at the University of Canterbury to characterise the engineering behaviour of the soils in the region was influenced by this event to focus on the performance of the highly variable ground conditions in the CBD. This paper outlines the methodology of this research to characterise the key soil horizons that underlie the CBD that influenced the performance of important structures during the recent earthquakes, and will influence the performance of the rebuilt city centre under future events. The methodology follows post-earthquake reconnaissance in the central city, a desk study on ground conditions, site selection, mobilisation of a post-earthquake ground investigation incorporating the cone penetration test (CPT), borehole drilling, shear wave velocity profiling and Gel-push sampling followed by a programme of laboratory testing including monotonic and cyclic testing of the soils obtained in the investigation. The research is timely and aims to inform the impending rebuild, with appropriate information on the soils response to dynamic loading, and the influence this has on the performance of structures with various foundation forms.
This paper presents an overview of the soil profile characteristics at strong motion station (SMS) locations in the Christchurch Central Business District (CBD) based on recently completed geotechnical site investigations. Given the variability of Christchurch soils, detailed investigations were needed in close vicinity to each SMS. In this regard, CPT, SPT and borehole data, and shear wave velocity (Vs) profiles from surface wave dispersion data in close vicinity to the SMSs have been used to develop detailed representative soil profiles at each site and to determine site classes according to the New Zealand standard NZS1170.5. A disparity between the NZS1170.5 site classes based on Vs and SPT N60 investigation techniques is highlighted, and additional studies are needed to harmonize site classification based on these techniques. The short period mode of vibration of soft deposits above gravels, which are found throughout Christchurch, are compared to the long period mode of vibration of the entire soil profile to bedrock. These two distinct modes of vibration require further investigation to determine their impact on the site response. According to current American and European approaches to seismic site classification, all SMSs were classified as problematic soil sites due to the presence of liquefiable strata, soils which are not directly accounted for by the NZS1170.5 approach.
A large number of businesses that used to be in the centre of Christchurch relocated after the earthquakes. Are they satisfied with their new locations and do they intend to return to the central city? We questioned 209 relocated businesses about their relocation history, present circumstances and future intentions. Many businesses were content with their new premises, despite having encountered a range of problems; those businesses that were questioned later in our survey period were more content. The average business in our sample rated the chances of moving back to the central city as around 50 %, but this varies with the type of business. Building height did not emerge as a major issue, but rents may be. The mix of types of business is likely to be different in the new city centre.
Since September 2010 Christchurch, New Zealand, has experienced a number of significant earthquakes. In addition to loss of life, this has resulted in significant destruction to infrastructure, including road corridors; and buildings, especially in the central city, where it has been estimated that 60% of buildings will need to be rebuilt. The rebuild and renewal of Christchurch has initially focused on the central city under the direction of the Christchurch City Council. This has seen the development of a draft Central City Plan that includes a number of initiatives that should encourage the use of the bicycle as a mode of transport. The rebuild and renewal of the remainder of the city is under the jurisdiction of a specially set up authority, the Christchurch Earthquake Recovery Authority (CERA). CERA reports to an appointed Minister for Canterbury Earthquake Recovery, who is responsible for coordinating the planning, spending, and actual rebuilding work needed for the recovery. Their plans for the renewal and rebuild of the remainder of the city are not yet known. This presentation will examine the potential role of the bicycle as a mode of transport in a rebuilt Christchurch. The presentation will start by describing the nature of damage to Christchurch as a result of the 2010 and 2011 earthquakes. It will then review the Central City Plan (the plan for the rebuild and renewal for central Christchurch) focusing particularly on those aspects that affect the role of the bicycle. The potential for the success of this plan will be assessed. It will specifically reflect on this in light of some recent research in Christchurch that examined the importance of getting infrastructure right if an aim of transport planning is to attract new people to cycle for utilitarian reasons.
The Canterbury earthquakes, which involved widespread damage in the February 2011 event and ongoing aftershocks near the Christchurch central business district (CBD), presented decision-makers with many recovery challenges. This paper identifies major government decisions, challenges, and lessons in the early recovery of Christchurch based on 23 key-informant interviews conducted 15 months after the February 2011 earthquake. It then focuses on one of the most important decisions – maintaining the cordon around the heavily damaged CBD – and investigates its impacts. The cordon displaced 50,000 central city jobs, raised questions about (and provided new opportunities for) the long-term viability of downtown, influenced the number and practice of building demolitions, and affected debris management; despite being associated with substantial losses, the cordon was commonly viewed as necessary, and provided some benefits in facilitating recovery. Management of the cordon poses important lessons for planning for catastrophic urban earthquakes around the world.
This research attempts to understand how the Christchurch rebuild is promoting urban liveability in the Central City, focussing on the influence of communities and neighbourhoods in this area. To do this, gathering the perceptions of Christchurch residents through surveys, a focus group and semi-structured interviews was carried out to see what aspects they believe contribute to creating more liveable places. These methods revealed that there are pockets of neighbourhoods and communities in the inner-city, but no overall sense of community. Results from the semi-structured interviews reinforced this; the current buyers of inner-city property are in the financial position to be able to do this, and they seem to be purchasing in this area due to convenience and investment rather than to join the existing communities in the area. Analysing the survey responses from Central City residents revealed contrasting results. Those currently living in the area felt there is a sense of community in the inner-city, but these are found in pockets of neighbourhoods around the Central City rather than in the overall area. The focus group revealed that community is further prioritised later in life, and that many of the community groups in the inner-city predominantly consist of those who have lived there since before the Christchurch Earthquake Series. However, participants of all three methods believed that the Central City is slowly becoming a lively and vibrant place. To improve urban liveability in the inner-city, it seems that prioritisation of the needs of current inner-city residents is required. Improving these neighbourhoods, whether it be through the implementation of services or providing more communal spaces, is needed to create stronger communities. The feelings of place, connectedness, and belonging that arise from being part of a community or well-connected neighbourhood can improve mental health and wellbeing, ultimately enhancing the overall health of the population as well as the perceived urban liveability of the area.
Organisations locate strategically within Business Districts (CBDs) in order to cultivate their image, increase their profile, and improve access to customers, suppliers, and services. While CBDs offer an economic benefit to organisations, they also present a unique set of hazard vulnerabilities and planning challenges for businesses. As of May 2012, the Christchurch CBD has been partially cordoned off for over 14 months. Economic activity within the cordoned CBD, which previously contained 6,000 businesses and over 51,000 workers, has been significantly diminished and organisations have been forced to find new ways of operating. The vulnerabilities and resilience of CBDs not only influences outcomes for CBD organisations, but also the broader interconnected (urban/regional/national) system. A CBD is a hub of economic, social, and built infrastructure within a network of links and nodes. When the hub is disrupted all of the people, objects, and transactions that usually flow into and out of the hub must be redirected elsewhere. In an urban situation this means traffic jams in peripheries of the city, increased prices of commercial property, and capital flight; all of which are currently being faced in Canterbury. This report presents the lessons learned from organisations in CBDs affected by the Canterbury earthquakes. Here we focus on the Christchurch CBD; however, several urban town centres were extensively disrupted by the earthquakes. The statistics and discussion presented in this report are based on the results of an ongoing study conducted by Resilient Organisations (www.resorgs.org.nz). The data was captured using two questionnaire surveys of Canterbury organisations (issued November 2010 and May 2011), interviews with key informants, and in-depth case studies of organisations. Several industry sectors were sampled, and geographic samples of organisations in the Christchurch CBD, Lyttelton, and the Kaiapoi town centre were also collected. Results in this report describing “non-CBD organisations” refer to all organisations outside of the Christchurch CBD, Lyttelton, and Kaiapoi town centres.
We examined changes in psychological distress experienced by residents of Christchurch following two catastrophic earthquakes in late 2010 and early 2011, using data from the New Zealand Attitudes and Values Study (NZAVS), a national probability panel study of New Zealand adults. Analyses focused on the 267 participants (172 women, 95 men) who were living in central Christchurch in 2009 (i.e., before the Christchurch earthquakes), and who also provided complete responses to our yearly panel questionnaire conducted in late 2010 (largely between the two major earthquakes), late 2011, and late 2012. Levels of psychological distress were similar across the different regions of central Christchurch immediately following the September 2010 earthquake, and remained comparable across regions in 2011. By late 2012, however, average levels of psychological distress in the regions had diverged as a function of the amount of property damage experienced within each given region. Specifically, participants in the least damaged region (i.e., the Fendalton-Waimairi and Riccarton-Wigram wards) experienced greater drops in psychological distress than did those in the moderately damaged region (i.e., across the Spreydon-Heathcote and Hagley- Ferrymead wards). However, the level of psychological distress reported by participants in the most damaged region (i.e., across Shirley-Papanui and Burwood-Pegasus) were not significantly different to those in the least damaged region of central Christchurch. These findings suggest that different patterns of psychological recovery emerged across the different regions of Christchurch, with the moderately damaged region faring the worst, but only after the initial shock of the destruction had passed.
This is an ethnographic case study, tracking the course of arguments about the future of a city’s central iconic building, damaged following a major earthquake sequence. The thesis plots this as a social drama and examines the central discourses of the controversy. The focus of the drama is the Anglican neo-Gothic Christ Church Cathedral, which stands in the central square of Christchurch, New Zealand. A series of major earthquakes in 2010/2011 devastated much of the inner city, destroying many heritage-listed buildings. The Cathedral was severely damaged and was declared by Government officials in 2011 to be a dangerous building, which needed to be demolished. The owners are the Church Property Trustees, chaired by Bishop Victoria Matthews, a Canadian appointed in 2008. In March 2012 Matthews announced that the Cathedral, because of safety and economic factors, would be deconstructed. Important artefacts were to be salvaged and a new Cathedral built, incorporating the old and new. This decision provoked a major controversy, led by those who claimed that the building could and should be restored. Discourses of history and heritage, memory, place and identity, ownership, economics and power are all identified, along with the various actors, because of their significance. However, the thesis is primarily concerned with the differing meanings given to the Cathedral. The major argument centres on the symbolic interaction between material objects and human subjects and the various ways these are interpreted. At the end of the research period, December 2015, the Christ Church Cathedral stands as a deteriorating wreck, inhabited by pigeons and rats and shielded by protective, colourfully decorated wooden fences. The decision about its future remains unresolved at the time of writing.
This paper presents the preliminary findings of a study on the resilience and recovery of organisations following the Darfield earthquake in New Zealand on 4 September 2010. Sampling included organisations proximal and distal to the fault trace, organisations located within central business districts, and organisations from seven diverse industry sectors. The research captured information on the challenges to, the impacts on, and the reflections of the organisations in the first months of recovery. Organisations in central business districts and in the hospitality sector were most likely to close while organisations that had perishable stock and livestock were more heavily reliant on critical services. Staff well-being, cash flow, and customer loss were major concerns for organisations across all sectors. For all organisations, the most helpful factors in mitigating the effects of the earthquake to be their relationship with staff, the design and type of buildings, and critical service continuity or swift reinstatement of services.
As a result of the Canterbury earthquakes, over 60% of the concrete buildings in the Christchurch Central Business District have been demolished. This experience has highlighted the need to provide guidance on the residual capacity and repairability of earthquake-damaged concrete buildings. Experience from 2010 Chile indicates that it is possible to repair severely damaged concrete elements (see photo at right), although limited testing has been performed on such repaired components. The first phase of this project is focused on the performance of two lightly-reinforced concrete walls that are being repaired and re-tested after damage sustained during previous testing.
The NMIT Arts & Media Building is the first in a new generation of multistorey timber structures. It employs an advanced damage avoidance earthquake design that is a world first for a timber building. Aurecon structural engineers are the first to use this revolutionary Pres-Lam technology developed at the University of Canterbury. This technology marks a fundamental change in design philosophy. Conventional seismic design of multi-storey structures typically depends on member ductility and the acceptance of a certain amount of damage to beams, columns and walls. The NMIT seismic system relies on pairs of coupled LVL shear walls that incorporate high strength steel tendons post-tensioned through a central duct. The walls are centrally fixed allowing them to rock during a seismic event. A series of U-shaped steel plates placed between the walls form a coupling mechanism, and act as dissipators to absorb seismic energy. The design allows the primary structure to remain essentially undamaged while readily replaceable connections act as plastic fuses. In this era where sustainability is becoming a key focus, the extensive use of timber and engineered-wood products such as LVL make use of a natural resource all grown and manufactured within a 100km radius of Nelson. This project demonstrates that there are now cost effective, sustainable and innovative solutions for multi-story timber buildings with potential applications for building owners in seismic areas around the world.
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.
This paper provides a comparison between the strong ground motions observed in the Christchurch central business district in the 4 September 2010 Mw7.1 Darfield, and 22 February 2011 Mw6.3 Christchurch earthquakes with those observed in Tokyo during the 11 March 2011 Mw9.0 Tohoku earthquake. Despite Tokyo being located approximately 110km from the nearest part of the causative rupture, the ground motions observed from the Tohoku earthquake were strong enough to cause structural damage in Tokyo and also significant liquefaction to loose reclaimed soils in Tokyo bay. Comparisons include the strong motion time histories, response spectra, significant durations and arias intensity. The implications for large earthquakes in New Zealand are also briefly discussed.
There has been little discussion of what archival accounting evidence can contribute to an understanding of a society’s response to a natural disaster. This article focuses on two severe earthquakes which struck New Zealand in 1929 and 1931 and makes two main contributions to accounting history. First, by discussing evidence from archival sources, it contributes to the literature on accounting in a disaster. This provides a basis for future theory building and for future comparative research related to the response to more recent natural disasters such as the 2010–11 Canterbury earthquakes. Secondly, it questions the conclusions of recently published research concerning the role of central and local government in this and recent earthquakes.
The Canterbury region of New Zealand experienced four earthquakes greater than MW 6.0 between September 2010 and December 2011. This study employs system dynamics as well as hazard, recovery and organisational literature and brings together data collected via surveys, case studies and interviews with organisations affected by the earthquakes. This is to show how systemic interactions and interdependencies within and between industry and geographic sectors affect their recovery post-disaster. The industry sectors in the study are: construction for its role in the rebuild, information and communication technology which is a regional high-growth industry, trucking for logistics, critical infrastructure, fast moving consumer goods (e.g. supermarkets) and hospitality to track recovery through non-discretionary and discretionary spend respectively. Also in the study are three urban centres including the region’s largest Central Business District, which has been inaccessible since the earthquake of 22 February 2011 to the time of writing in February 2013. This work also highlights how earthquake effects propagated between sectors and how sectors collaborated to mitigate difficulties such as product demand instability. Other interacting factors are identified that influence the recovery trajectories of the different industry sectors. These are resource availability, insurance payments, aid from central government, and timely and quality recovery information. This work demonstrates that in recovering from disaster it is crucial for organisations to identify what interacting factors could affect their operations. Also of importance are efforts to reduce the organisation’s vulnerability and increase their resilience to future crises and in day-to-day operations. Lastly, the multi-disciplinary approach to understanding the recovery and resilience of organisations and industry sectors after disaster, leads to a better understanding of effects as well as more effective recovery policy.
The Canterbury earthquake and aftershock sequence in New Zealand during 2010-2011 subjected the city’s structures to a significant accumulated cyclic demand and raised significant questions regarding the low-cycle fatigue demands imposed upon the structures. There is a significant challenge to quantify the level of cumulative demand imposed on structures and to assess the percentage of a structure's fatigue life that has been consumed as a result of this earthquake sequence. It is important to be able to quantify the cumulative demand to determine how a building will perform in a subsequent large earthquake and inform repair and re-occupancy decisions. This paper investigates the cumulative fatigue demand for a structure located within the Christchurch Central Business District (CBD). Time history analysis and equivalent cycle counting methods are applied across the Canterbury earthquake sequence, using key events from September 4th 2010 and February 22nd , 2011 main shocks. The estimate of the cumulative fatigue demand is then compared to the expected capacity of a case study reinforced concrete bridge pier, to undertake a structure-specific fatigue assessment. The analysis is undertaken to approximate the portion of the structural fatigue capacity that has been consumed, and how much residual capacity remains. Results are assessed for recordings at the four Christchurch central city strong motion recording sites installed by the GeoNet programme, to provide an estimate of variation in results. The computed cyclic demand results are compared to code-based design methods and as assessment of the inelastic displacement demand of the reinforcing steel. Results are also presented in a fragility context where a de minimis (inconsequential), irreparable damage and full fatigue fracture are defined to provide a probabilistic assessment of the fatigue damage incurred. This methodology can provide input into the overall assessment of fatigue demands and residual capacity.
Recent surface-rupturing earthquakes in New Zealand have highlighted significant exposure and vulnerability of the road network to fault displacement. Understanding fault displacement hazard and its impact on roads is crucial for mitigating risks and enhancing resilience. There is a need for regional-scale assessments of fault displacement to identify vulnerable areas within the road network for the purposes of planning and prioritising site-specific investigations. This thesis employs updated analysis of data from three historical surface-rupturing earthquakes (Edgecumbe 1987, Darfield 2010, and Kaikoūra 2016) to develop an empirical model that addresses the gap in regional fault displacement hazard analysis. The findings contribute to understanding of • How to use seismic hazard model inputs for regional fault displacement hazard analysis • How faulting type and sediment cover affects the magnitude and spatial distribution of fault displacement • How the distribution of displacement and regional fault displacement hazard is impacted by secondary faulting • The inherent uncertainties and limitations associated with employing an empirical approach at a regional scale • Which sections of New Zealand’s roading network are most susceptible to fault displacement hazard and warrant site-specific investigations • Which regions should prioritise updating emergency management plans to account for post-event disruptions to roading. I used displacement data from the aforementioned historical ruptures to generate displacement versus distance-to-fault curves for various displacement components, fault types, and geological characteristics. Using those relationships and established relationships for along-strike displacement, displacement contours were generated surrounding active faults within the NZ Community Fault Model. Next, I calculated a new measure of 1D strain along roads as well as relative hazard, which integrated 1D strain and normalised slip rate data. Summing these values at the regional level identified areas of heightened relative hazard across New Zealand, and permits an assessment of the susceptibility of road networks using geomorphon land classes as proxies for vulnerability. The results reveal that fault-parallel displacements tend to localise near the fault plane, while vertical and fault-perpendicular displacements sustain over extended distances. Notably, no significant disparities were observed in off-fault displacement between the hanging wall and footwall sides of the fault, or among different surface geology types, potentially attributed to dataset biases. The presence of secondary faulting in the dataset contributes to increased levels of tectonic displacement farther from the fault, highlighting its significance in hazard assessments. Furthermore, fault displacement contours delineate broader zones around dip-slip faults compared to strike-slip faults, with correlations identified between fault length and displacement width. Road ‘strain’ values are higher around dip-slip faults, with notable examples observed in the Westland and Buller Districts. As expected, relative hazard analysis revealed elevated values along faults with high slip rates, notably along the Alpine Fault. A regional-scale analysis of hazard and exposure reveals heightened relative hazard in specific regions, including Wellington, Southern Hawke’s Bay, Central Bay of Plenty, Central West Coast, inland Canterbury, and the Wairau Valley of Marlborough. Notably, the Central West Coast exhibits the highest summed relative hazard value, attributed to the fast-slipping Alpine Fault. The South Island generally experiences greater relative hazard due to larger and faster-slipping faults compared to the North Island, despite having fewer roads. Central regions of New Zealand face heightened risk compared to Southern or Northern regions. Critical road links intersecting high-slipping faults, such as State Highways 6, 73, 1, and 2, necessitate prioritisation for site-specific assessments, emergency management planning and targeted mitigation strategies. Roads intersecting with the Alpine Fault are prone to large parallel displacements, requiring post-quake repair efforts. Mitigation strategies include future road avoidance of nearby faults, modification of road fill and surface material, and acknowledgement of inherent risk, leading to prioritised repair efforts of critical roads post-quake. Implementing these strategies enhances emergency response efforts by improving accessibility to isolated regions following a major surface-rupturing event, facilitating faster supply delivery and evacuation assistance. This thesis contributes to the advancement of understanding fault displacement hazard by introducing a novel regional, empirical approach. The methods and findings highlight the importance of further developing such analyses and extending them to other critical infrastructure types exposed to fault displacement hazard in New Zealand. Enhancing our comprehension of the risks associated with fault displacement hazard offers valuable insights into various mitigation strategies for roading infrastructure and informs emergency response planning, thereby enhancing both national and global infrastructure resilience against geological hazards.
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.
On 4 September 2010 the Magnitude 7.1 'Darfield' Earthquake marked the beginning of the Canterbury earthquake sequence. The Darfield earthquake produced strong ground shaking throughout the centralCanterbury Plains, affecting rural areas, small towns and the city of Christchurch. The event produced a 29km long surface rupture through intensive farmland, causing localised flooding and liquefaction. The central Canterbury plains were subjected to a sustained period of thousands of aftershocks in the months after the Darfield earthquake. The primary sector is a major component of the in New Zealand economy. Business units are predominantly small family-run farm organisations, though there are increasing levels of corporate farming. The agribusiness sector contributes 20 per cent of real GDP and 47 per cent of total exports for New Zealand. Of the approximately 2,000 farms that are located in the Canterbury Plains, the most common farming sectors in the region are Mixed farming (mostly comprised of sheep and/or beef farming), Dairy farming, and Arable farming (cropping). Many farms on the Canterbury Plains require some form of irrigation and are increasingly capital intensive, reliant on built infrastructure, technology and critical services. Farms are of great significance to their local rural economies, with many rural non-farming organisations dependent on the health of local farming organisations. Despite the economic significance of the sector, there have been few, if any studies analysing how modern intensive farms are affected by earthquakes. The aim of this report is to (1) summarise the impacts the Darfield earthquake had on farming organisations and outline in general terms how farms are vulnerable to the effects of an earthquake; (2) identify what factors helped mitigate earthquake-related impacts. Data for this paper was collected through two surveys of farming and rural non-farming organisations following the earthquake and contextual interviews with affected organisations. In total, 78 organisations participated in the study (Figure 1). Farming organisations represented 72% (N=56) of the sample.
The 2010-2011 Canterbury Earthquakes brought devastation to the city of Christchurch and has irrevocably affected the lives of the city’s residents. Years after the conclusion of these earthquakes, Christchurch and its residents are well on the path to recovery. Crime has proven an ongoing topic of discussion throughout this period, with news reports of increased burglary and arson in areas left largely abandoned by earthquake damage, and a rise in violent crime in suburban areas of Christchurch. Following the body of research that has considered the reaction of crime to natural disasters, this research has sought to comprehensively examine and understand the effects that the Canterbury Earthquakes had on crime. Examining Christchurch-wide offending, crime rates fell over the study period (July 2008 to June 2013), with the exception of domestic violence. Aside from a momentary increase in burglary in the days immediately following the Christchurch Earthquake, crime rates (as of 2013) have remained largely below pre-earthquake levels. Using Dual Kernel Density Estimation Analysis, a distinct spatial change in pre-earthquake crime hotspots was observed. These changes included an enormous decrease in central city offences, a rise in burglary in the eastern suburbs, and an increase in assault in areas outside of the central city. Logistic regression analysis, using a time-compensated dependent variable, identified a number of statistically-significant relationships between per CAU crime rate change and factors measuring socio-demographic characteristics, community cohesion, and the severity of disaster effects. The significance of these findings was discussed using elements of Social Disorganisation Theory, Routine Activity Theory, and Strain Theory. Consistent with past findings, social order was largely maintained following the Canterbury Earthquakes, with suggestion that increased collective efficacy and therapeutic communities had a negative influence on crime in the post-earthquake period. Areas of increased burglary and assault were associated with large population decreases, suggesting a link with the dissolution of communities and the removal of their inherent informal guardianship. Though observed, the increase in domestic violence was not associated with most neighbourhood-level variables. Trends in crime after the Canterbury Earthquakes were largely consistent with past research, and the media’s portrayal.
In the period between September 2010 and December 2011, Christchurch (New Zealand) and its surroundings were hit by a series of strong earthquakes including six significant events, all generated by local faults in proximity to the city: 4 September 2010 (Mw=7.1), 22 February 2011 (Mw=6.2), 13 June 2011 (Mw=5.3 and Mw=6.0) and 23 December 2011 (M=5.8 and (M=5.9) earthquakes. As shown in Figure 1, the causative faults of the earthquakes were very close to or within the city boundaries thus generating very strong ground motions and causing tremendous damage throughout the city. Christchurch is shown as a lighter colour area, and its Central Business District (CBD) is marked with a white square area in the figure. Note that the sequence of earthquakes started to the west of the city and then propagated to the south, south-east and east of the city through a set of separate but apparently interacting faults. Because of their strength and proximity to the city, the earthquakes caused tremendous physical damage and impacts on the people, natural and built environments of Christchurch. The 22 February 2011 earthquake was particularly devastating. The ground motions generated by this earthquake were intense and in many parts of Christchurch substantially above the ground motions used to design the buildings in Christchurch. The earthquake caused 182 fatalities, collapse of two multi-storey reinforced concrete buildings, collapse or partial collapse of many unreinforced masonry structures including the historic Christchurch Cathedral. The Central Business District (CBD) of Christchurch, which is the central heart of the city just east of Hagley Park, was practically lost with majority of its 3,000 buildings being damaged beyond repair. Widespread liquefaction in the suburbs of Christchurch, as well as rock falls and slope/cliff instabilities in the Port Hills affected tens of thousands of residential buildings and properties, and shattered the lifelines and infrastructure over approximately one third of the city area. The total economic loss caused by the 2010-2011 Christchurch earthquakes is currently estimated to be in the range between 25 and 30 billion NZ dollars (or 15% to 18% of New Zealand’s GDP). After each major earthquake, comprehensive field investigations and inspections were conducted to document the liquefaction-induced land damage, lateral spreading displacements and their impacts on buildings and infrastructure. In addition, the ground motions produced by the earthquakes were recorded by approximately 15 strong motion stations within (close to) the city boundaries providing and impressive wealth of data, records and observations of the performance of ground and various types of structures during this unusual sequence of strong local earthquakes affecting a city. This paper discusses the liquefaction in residential areas and focuses on its impacts on dwellings (residential houses) and potable water system in the Christchurch suburbs. The ground conditions of Christchurch including the depositional history of soils, their composition, age and groundwater regime are first discussed. Detailed liquefaction maps illustrating the extent and severity of liquefaction across Christchurch triggered by the sequence of earthquakes including multiple episodes of severe re-liquefaction are next presented. Characteristic liquefaction-induced damage to residential houses is then described focussing on the performance of typical house foundations in areas affected by liquefaction. Liquefaction impacts on the potable water system of Christchurch is also briefly summarized including correlation between the damage to the system, liquefaction severity, and the performance of different pipe materials. Finally, the characteristics of Christchurch liquefaction and its impacts on built environment are discussed in relation to the liquefaction-induced damage in Japan during the 11 March 2011 Great East Japan Earthquake.
Novel Gel-push sampling was employed to obtain high quality samples of Christchurch sands from the Central Business District, at sites where liquefaction was observed in 22 February 2011, and 13 June 2011 earthquakes. The results of cyclic triaxial testing on selected undisturbed specimens of typical Christchurch sands are presented and compared to empirical procedures used by practitioners. This comparison suggests cyclic triaxial data may be conservative, and the Magnitude Scaling Factor used in empirical procedures may be unconservative for highly compressible soils during near source moderate to low magnitude events. Comparison to empirical triggering curves suggests the empirical method generally estimates the cyclic strength of Christchurch sands within a reasonable degree of accuracy as a screening evaluation tool for liquefaction hazard, however for sands with moderate to high fines content it may be significantly unconservative, highlighting the need for high quality sampling and testing on important projects where seismic performance is critical.
This paper presents insights from recent advanced laboratory testing of undisturbed and reconstituted specimens of Christchurch silty-sands. The purpose of the testing was to establish the cyclic strength of silty-sands from sites in the Central Business District (CBD), where liquefaction was observed in 4 September 2010, 22 February 2011, and 13 June 2011. Similar overall strengths were obtained from undisturbed and reconstituted tests prepared at similar densities, albeit with higher variability for the reconstituted specimens. Reconstituted specimens exhibited distinctly different response in terms of lower compressibility during initial loading cycles, and exhibited a more brittle response when large strains were mobilised, particularly for samples with high fines content. Given the lower variability in natural sample response and the possibility of age-related strength to be significant for sites not subjected to earthquakes, high quality undisturbed samples are recommended over the use of reconstituted specimens to establish the cyclic strength of natural sands.
Context of the project: On 4 September 2010, 22 February 2011, 13 June 2011 and 23 December 2011 Christchurch suffered major earthquakes and aftershocks (well over 10,000) that have left the central city in ruins and many of the eastern suburbs barely habitable even now. The earthquakes on 22 February caused catastrophic loss of life with 185 people killed. The toll this has taken on the residents of Christchurch has been considerable, not least of all for the significant psychological impact and disruption it has had on the children. As the process of rebuilding the city commenced, it became clear that the arts would play a key role in maintaining our quality of life during difficult times. For me, this started with the children and the most expressive of all the art forms – music.
This paper presents an examination of ground motion observations from 20 near-source strong motion stations during the most significant 10 events in the 2010-2011 Canterbury earthquake to examine region-specific systematic effects based on relaxing the conventional ergodic assumption. On the basis of similar site-to-site residuals, surfical geology, and geographical proximity, 15 of the 20 stations are grouped into four sub-regions: the Central Business District; and Western, Eastern, and Northern suburbs. Mean site-to-site residuals for these sub-regions then allows for the possibility of non-ergodic ground motion prediction over these sub-regions of Canterbury, rather than only at strong motion station locations. The ratio of the total non-ergodic vs. ergodic standard deviation is found to be, on average, consistent with previous studies, however it is emphasized that on a site-by-site basis the non-ergodic standard deviation can easily vary by ±20%.
The performance of conventionally designed reinforced concrete (RC) structures during the 2011 Christchurch earthquake has demonstrated that there is greater uncertainty in the seismic performance of RC components than previously understood. RC frame and wall structures in the Christchurch central business district were observed to form undesirable cracks patterns in the plastic hinge region while yield penetration either side of cracks, and into development zones, were less than theoretical predictions. The implications of this unexpected behaviour: (i) significantly less available ductility; (ii) less hysteretic energy dissipation; and (iii) the localization of peak reinforcement strains, results in considerable doubt for the residual capacity of RC structures. The significance of these consequences has prompted a review of potential sources of uncertainty in seismic experimentation with the intention to improve the current confidence level for newly designed conventional RC structures. This paper attempts to revisit the principles of RC mechanics, in particular, to consider the influence of loading history, concrete tensile strength, and reinforcement ratio on the performance of ‘real’ RC structures compared to experimental test specimens.
Disaster recovery is significantly affected by funding availability. The timeliness and quality of recovery activities are not only impacted by the extent of the funding but also the mechanisms with which funding is prioritised, allocated and delivered. This research addresses the impact of funding mechanisms on the effectiveness and efficiency of post-disaster demolition and debris management programmes. A qualitative assessment of the impacts on recovery of different funding sources and mechanisms was carried out, using the 2010 Canterbury Earthquake as well as other recent international events as case studies. The impacts assessed include: timeliness, completeness, environmental, economic and social impacts. Of the case studies investigated, the Canterbury Earthquake was the only disaster response to rely solely on a privatised approach to insurance for debris management. Due to the low level of resident displacement and low level of hazard in the waste, this was a satisfactory approach, though not ideal. This approach has led to greater organisational complexity and delays. For many other events, the potential community wide impacts caused by the prolonged presence of disaster debris means that publicly funded and centrally facilitated programmes appear to be the most common and effective method of managing disaster waste.
In the wake of the Canterbury earthquakes, one of the biggest threats to our heritage buildings is the risk of earthquakes and the associated drive to strengthen or demolish buildings. Can Small Town NZ balance the requirements of the EQPB legislation and economic realities of their places? The government’s priority is on safety of building occupants and citizens in the streets. However, maintaining and strengthening privately-owned heritage buildings is often cost prohibitive. Hence, heritage regulation has frequently been perceived as interfering with private property rights, especially when heritage buildings occupy a special place in the community becoming an important place for people (i.e. public benefits are larger than private). We investigate several case studies where building owners have been given green light to demolish heritage listed buildings to make way for modern developments. In two of the case studies developers provided evidence of unaffordable strengthening costs. A new trend that has emerged is a voluntary offer of contributing to an incentive fund to assist with heritage preservation of other buildings. This is a unique example where private owners offer incentives (via council controlled organisations) instead of it being purely the domain of the central or local governments.
