Following the 22 February 2011, MW 6.2 earthquake located on a fault beneath the Port Hills of Christchurch, fissuring of up to several hundred metres in length was observed in the loess and loess-colluvium of foot-slope positions in north-facing valleys of the Port Hills. The fissuring was observed in all major valleys, occurred at similar low altitudes, showing a contour-parallel orientation and often accompanied by both lateral compression/extension features and spring formation in the valley floor below. Fissuring locations studied in depth included Bowenvale Valley, Hillsborough Valley, Huntlywood Terrace–Lucas Lane, Bridle Path Road, and Maffeys Road–La Costa Lane. Investigations into loess soil, its properties and mannerisms, as well as international examples of its failure were undertaken, including study of the Loess Plateau of China, the Teton Dam, and palaeo-fissuring on Banks Peninsula. These investigations lead to the conclusion that loess has the propensity to fail, often due to the infiltration of water, the presence of which can lead to its instantaneous disaggregation. Literature study and laboratory analysis of Port Hills loess concluded that is has the ability to be stable in steep, sub-vertical escarpments, and often has a sub-vertically jointed internal structure and has a peak shear strength when dry. Values for cohesion, c (kPa) and the internal friction angle, ϕ (degrees) of Port Hills loess were established. The c values for the 40 Rapaki Road, 3 Glenview Terrace loess samples were 13.4 kPa and 19.7 kPa, respectively. The corresponding ϕ values were thought unusually high, at 42.0° and 43.4°.The analysed loess behaved very plastically, with little or no peak strength visible in the plots as the test went almost directly to residual strength. A geophysics resistivity survey showed an area of low resistivity which likely corresponds to a zone of saturated clayey loess/loess colluvium, indicating a high water table in the area. This is consistent with the appearances of local springs which are located towards the northern end of each distinct section of fissure trace and chemical analysis shows that they are sourced from the Port Hills volcanics. Port Hills fissuring may be sub-divided into three categories, Category A, Category B, and Category C, each characterised by distinctive features of the fissures. Category A includes fissures which display evidence of, spring formation, tunnel-gullying, and lateral spreading-like behaviour or quasi-toppling. These fissures are several metres down-slope of the loess-bedrock interface, and are in valleys containing a loess-colluvium fill. Category B fissures are in wider valleys than those in Category A, and the valleys contain estuarine silty sediments which liquefied during the earthquake. Category C fissures occurred at higher elevations than the fissures in the preceding categories, being almost coincident with bedrock outcropping. It is believed that the mechanism responsible for causing the fissuring is a complex combination of three mechanisms: the trampoline effect, bedrock fracturing, and lateral spreading. These three mechanisms can be applied in varying degrees to each of the fissuring sites in categories A, B, and C, in order to provide explanation for the observations made at each. Toppling failure can describe the soil movement as a consequence of the a three causative mechanisms, and provides insight into the movement of the loess. Intra-loess water coursing and tunnel gullying is thought to have encouraged and exacerbated the fissuring, while not being the driving force per se. Incipient landsliding is considered to be the least likely of the possible fissuring interpretations.
On February 22, 2011, Christchurch-based journalists were jolted out of their normal work routine by a large 6.3 magnitude earthquake that killed 185 people, wrecked the city and forced reporters to reappraise their journalism. This study considers how the earthquake affected journalists’ relationship to the community, their use of sources and news selection. A theory of collective trauma is used to explain the changes that journalists made to their reporting practice. Specifically, Christchurch journalists had a greater identification and attachment to their audience post-earthquake. Journalists viewed themselves as part of the earthquake story, which prompted them to view sources differently, use those sources differently and see advocacy as a keystone of their news work after the disaster. This study adds to a growing scholarship about journalists and trauma, but focuses on what the event meant for local reporters’ choice of sources and news selection rather than measuring rates of psychological distress.
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.
On 22 February 2011, Ōtautahi Christchurch was struck by a devastating earthquake. The city was changed forever: lives were lost, buildings destroyed and much of the city’s infrastructure needed to be repaired or replaced. One of the unexpected outcomes of the process of recovery was the volume of archaeological work that was carried out in the city, including the substantial amount of buildings archaeology that was undertaken (that is, recording standing buildings prior to and during their demolition, using archaeological techniques). Amongst the numerous buildings recorded in this way were 101 houses from across the city (but concentrated in those areas hit hardest by the earthquakes), built between 1850 and 1900. This work yielded a wealth of data about what houses in the city looked like in the nineteenth century. It is this data that forms the core of my thesis, providing an opportunity to examine the question of what life was like in nineteenth century Christchurch through these houses and the people who built them. Christchurch was founded in 1850 by European settlers, most of whom were English. These people came to New Zealand to build a better life for themselves and their families. For many of them, this ‘better life’ included the possibility of owning their own home and, in some instances, building that house (or at least, commissioning its construction). The buildings archaeology data collected following the Canterbury earthquakes enabled a detailed analysis of what houses in the city looked like in the nineteenth century – their form, and both their external and internal appearance – and how this changed as the century progressed. A detailed examination of the lives of those who built 21 of the houses enabled me to understand why each house looked the way it did, and how the interplay of class, budget and family size and expectations (amongst other factors) shaped each house. It is through these life stories that more about life in Christchurch in the nineteenth century was revealed. These are stories of men and women, of success and failure, of businesses and bankruptcies. There are themes that run through the stories: class, appearances, death, religion, gender, improvement. Just as importantly, though, they reveal the everyday experiences of people as they set about building a new city. Thus, through the archaeology of the houses and the history of the people who built them, an earthquake has revealed more about life in nineteenth century Christchurch, as well as providing the means for a deeper understanding of the city’s domestic architecture.
Triple P parenting programmes have provided promising results for children and families in recent years. The aim of the current project was to explore the experiences of families leading up to participating in a Teen Triple P programme three years following the Christchurch earthquakes and their need for assistance in the management of their teenagers. Parents were interviewed prior to the commencement of the Teen Triple P programme and after its completion. Parents were also asked to complete a journal entry or engage in two brief telephone conversations with the researcher outlining their experiences with the Teen Triple P programme. These outlined the perceived fit of the programme to the needs of the family. Parents provided insight into their family’s experiences of the Christchurch 2010 and 2011 series of earthquakes and the perceived impact this had on their lives and the management of their teenagers. The results indicated that parents felt more positively about their parenting behaviours post-programme and were able to identify changes in their teen and/or family that they felt were as a response to participation in Teen Triple P. Parents provided rich descriptions of their earthquake experiences and the immediate and long-term impacts they endured both individually and as a family. Parents did not feel that the earthquakes fed into their decision to do a Teen Triple P Programme. The results helped improve our understanding of the effectiveness of Teen Triple P as a parenting programme as well increased our understanding of the challenges and needs of families in post-earthquake Christchurch.
This thesis is concerned with springs that appeared in the Hillsborough, Christchurch during the 2010-2011 Canterbury Earthquake Sequence, and which have continued to discharge groundwater to the surface to the present time. Investigations have evolved, measurements of discharge at selected sites, limited chemical data on anions and isotope analysis. The springs are associated with earthquake generated fissures (extensional) and compression zones, mostly in loess-colluvium soils of the valley floor and lower slopes. Extensive peat swamps are present in the Hillsborough valley, with a groundwater table at ~1m below ground. The first appearance of the ‘new’ springs took place following the Mw 7.1 Darfield Earthquake on 4 September 2010, and discharges increased both in volume and extent of the Christchurch Mw 6.3 Earthquake of 22 February 2011. Five monitored sites show flow rates in the range of 4.2-14.4L/min, which have remained effectively constant for the duration of the study (2014-2015). Water chemistry analysis shows that the groundwater discharges are sourced primarily from volcanic bedrocks which underlies the valley at depths ≤50m below ground level. Isotope values confirm similarities with bedrock-sourced groundwater, and the short term (hours-days) influence of extreme rainfall events. Cyclone Lusi (2013-2014) affects were monitored and showed recovery of the bedrock derived water signature within 72 hours. Close to the mouth of the valley sediments interfinger with Waimakiriri River derived alluvium bearing a distinct and different isotope signature. Some mixing is evident at certain locations, but it is not clear if there is any influence from the Huntsbury reservoir which failed in the Port Hills Earthquake (22 February 2011) and stored groundwater from the Christchurch artesian aquifer system (Riccarton Gravel).
With the occurrence of natural disasters on the increase, major cities around the world face the potential of complete loss of infrastructure due to design guidelines that do not consider resilience in the design. With the February 22nd, 2011 earthquake in Christchurch, being the largest insured event, lessons learnt from the rebuild will be vital for the preparation of future disasters. Therefore the objective of this research is to understand the financial implications of the changes to the waste water design guidelines used throughout the five year rebuild programme of works. The research includes a study of the SCIRT alliance model selected for the delivery that is flexible enough to handle changes in the design with minimal impact on the direct cost of the rebuild works. The study further includes the analysis and compares the impact of the three different guidelines on maintenance and replacement cost over the waste water pipe asset life. The research concludes that with the varying ground conditions in Christchurch and also the wide variety of materials in use in the waste water network up to the start of the CES, the rebuild was not a ‘one size fits all’ approach.
The 2010–2011 Canterbury earthquakes, which involved widespread damage during the February 2011 event and ongoing aftershocks near the Christchurch Central Business District, left this community with more than $NZD 40 billion in losses (~20 % GDP), demolition of approximately 60 % of multi-storey concrete buildings (3 storeys and up), and closure of the core business district for over 2 years. The aftermath of the earthquake sequence has revealed unique issues and complexities for the owners of commercial and multi-storey residential buildings in relation to unexpected technical, legal, and financial challenges when making decisions regarding the future of their buildings impacted by the earthquakes. The paper presents a framework to understand the factors influencing post-earthquake decisions (repair or demolish) on multi-storey concrete buildings in Christchurch. The study, conducted in 2014, includes in-depth investigations on 15 case-study buildings using 27 semi-structured interviews with various property owners, property managers, insurers, engineers, and government authorities in New Zealand. The interviews revealed insights regarding the multitude of factors influencing post-earthquake decisions and losses. As expected, the level of damage and repairability (cost to repair) generally dictated the course of action. There is strong evidence, however, that other variables have significantly influenced the decision on a number of buildings, such as insurance, business strategies, perception of risks, building regulations (and compliance costs), and government decisions. The decision-making process for each building is complex and unique, not solely driven by structural damage. Furthermore, the findings have put the spotlight on insurance policy wordings and the paradoxical effect of insurance on the recovery of Christchurch, leading to other challenges and issues going forward.
The Christchurch region of New Zealand experienced a series of major earthquakes and aftershocks between September 2010 and June 2011 which caused severe damage to the city’s infrastructure. The performance of tilt-up precast concrete buildings was investigated and initial observations are presented here. In general, tilt-up buildings performed well during all three major earthquakes, with mostly only minor, repairable damage occurring. For the in-plane loading direction, both loadbearing and cladding panels behaved exceptionally well, with no significant damage or failure observed in panels and their connections. A limited number of connection failures occurred due to large out-of-plane panel inertia forces. In several buildings, the connections between the panel and the internal structural frame appeared to be the weakest link, lacking in both strength and ductility. This weakness in the out-of-plane load path should be prevented in future designs.
As part of the 'Project Masonry' Recovery Project funded by the New Zealand Natural Hazards Research Platform, commencing in March 2011, an international team of researchers was deployed to document and interpret the observed earthquake damage to masonry buildings and to churches as a result of the 22nd February 2011 Christchurch earthquake. The study focused on investigating commonly encountered failure patterns and collapse mechanisms. A brief summary of activities undertaken is presented, detailing the observations that were made on the performance of and the deficiencies that contributed to the damage to approximately 650 inspected unreinforced clay brick masonry (URM) buildings, to 90 unreinforced stone masonry buildings, to 342 reinforced concrete masonry (RCM) buildings, to 112 churches in the Canterbury region, and to just under 1100 residential dwellings having external masonry veneer cladding. In addition, details are provided of retrofit techniques that were implemented within relevant Christchurch URM buildings prior to the 22nd February earthquake and brief suggestions are provided regarding appropriate seismic retrofit and remediation techniques for stone masonry buildings. http://www.nzsee.org.nz/publications/nzsee-quarterly-bulletin/
The 2010 Darfield earthquake is the largest earthquake on record to have occurred within 40 km of a major city and not cause any fatalities. In this paper the authors have reflected on their experiences in Christchurch following the earthquake with a view to what worked, what didn’t, and what lessons can be learned from this for the benefit of Australian earthquake preparedness. Owing to the fact that most of the observed building damage occurred in Unreinforced Masonry (URM) construction, this paper focuses in particular on the authors’ experience conducting rapid building damage assessment during the first 72 hours following the earthquake and more detailed examination of the performance of unreinforced masonry buildings with and without seismic retrofit interventions.
Indigenous Peoples retain traditional coping strategies for disasters despite the marginalisation of many Indigenous communities. This article describes the response of Māori to the Christchurch earthquakes of 2010 and 2012 through analyses of available statistical data and reports, and interviews done three months and one year after the most damaging event. A significant difference between Māori and ‘mainstream’ New Zealand was the greater mobility enacted by Māori throughout this period, with organisations having roles beyond their traditional catchments throughout the disaster, including important support for non-Māori. Informed engagement with Indigenous communities, acknowledging their internal diversity and culturally nuanced support networks, would enable more efficient disaster responses in many countries.
The majority of current procedures used to deduce liquefaction potential of soils rely on empirical methods. These methods have been proven to work in the past, but these methods are known to overestimate the liquefaction potential in certain regions of Christchurch due to a whole range of factors, and the theoretical basis behind these methods cannot be explained scientifically. Critical state soil mechanics theory was chosen to provide an explanation for the soil's behaviour during the undrained shearing. Soils from two sites in Christchurch were characterised at regular intervals for the critical layers and tested for the critical state lines (CSL). Various models and relationships were then used to predict the CSL and compared with the actual CSL. However none of the methods used managed to predict the CSL accurately, and a separate Christchurch exclusive relationship was proposed. The resultant state parameter values could be obtained from shear-wave velocity plots and were then developed into cyclic resistance ratios (CRR). These were subsequently compared with cyclic stress ratios (CSR) from recent Christchurch earthquakes to obtain the factor of safety. This CSL-based approach was compared with other empirical methods and was shown to yield a favourable relationship with visual observations at the sites' locations following the earthquake.
A magnitude 6.3 earthquake struck the city of Christchurch at 12:51pm on Tuesday 22 February 2011. The earthquake caused 182 fatalities, a large number of injuries, and resulted in widespread damage to the built environment, including significant disruption to the lifelines. The event created the largest lifeline disruption in a New Zealand city in 80 years, with much of the damage resulting from extensive and severe liquefaction in the Christchurch urban area. The Christchurch earthquake occurred when the Canterbury region and its lifelines systems were at the early stage of recovering from the 4 September 2010 Darfield (Canterbury) magnitude 7.1 earthquake. This paper describes the impact of the Christchurch earthquake on lifelines by briefly summarising the physical damage to the networks, the system performance and the operational response during the emergency management and the recovery phase. Special focus is given to the performance and management of the gas, electric and road networks and to the liquefaction ejecta clean-up operations that contributed to the rapid reinstatement of the functionality of many of the lifelines. The water and wastewater system performances are also summarized. Elements of resilience that contributed to good network performance or to efficient emergency and recovery management are highlighted in the paper.
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 summarizes the development of a region-wide surficial shear wave velocity model based on the combination of the large high-spatial-density database of cone penetration test (CPT) logs in and around Christchurch, New Zealand and a recently-developed Christchurch-specific empirical correlation between soil shear wave velocity and CPT. The ongoing development of this near-surface shear wave velocity model has applications for site characterization efforts via the development of maps of time-averaged shear wave velocities over specific depths, and the identification of regional similarities and differences in soil shear stiffness.
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Results from cyclic undrained direct simple shear tests on reconstituted specimens of two sands from Christchurch are compared against the liquefaction resistance inferred from CPT-based empirical liquefaction triggering methods. Limitations in existing empirical triggering relationships to capture important effects related to processes which originated test soils are highlighted and discussed.
The city of Christchurch has experienced over 10,000 aftershocks since the 4th of September 2010 earthquake of which approximately 50 have been greater than magnitude 5. The damage caused to URM buildings in Christchurch over this sequence of earthquakes has been well documented. Due to the similarity in age and construction of URM buildings in Adelaide, South Australia and Christchurch (they are sister cities, of similar age and heritage), an investigation was conducted to learn lessons for Adelaide based on the Christchurch experience. To this end, the number of URM buildings in the central business districts of both cities, the extent of seismic strengthening that exists in both cities, and the relative earthquake hazards for both cities were considered. This paper will report on these findings and recommend strategies that the city of Adelaide could consider to significantly reduce the seismic risk posed by URM buildings in future earthquake.
The earthquake sequence has resulted in significant physical and reputational damage to the Canterbury tourism industry. Eighteen months after the earthquakes inbound tourism data is still below pre-earthquake levels, with Canterbury operators reporting that the industry has not bounced back to where it was before September 2010. Outcomes of the earthquakes on business performance highlight there were winners and losers in the aftermath. Recovery of inbound tourism markets is closely tied to the timeframe to rebuild the CBD of Christchurch. Reinstating critical tourism infrastructure will drive future tourism investment, and allow tourism businesses to regenerate and thrive into the future. A blueprint for rebuilding the CBD of Christchurch was released by the Christchurch City Council in July 2012, and has been well received by tourism stakeholders in the region. The challenge now is for city officials to fund the development projects outlined in the blueprint, and to rebuild the CBD as quickly as possible in order to help regenerate the tourism industry in Christchurch, Canterbury and the rest of the South Island
The 2011, 6.3 magnitude Christchurch earthquake in New Zealand caused considerable structural damage. It is believed that this event has now resulted in demolition of about 65-70% of the building stock in the Central Business District (CBD), significantly crippling economic activities in the city of Christchurch. A major concern raised from this event was adequacy of the current seismic design practice adopted for reinforced concrete walls due to their poor performance in modern buildings. The relatively short-duration earthquake motion implied that the observed wall damage occurred in a brittle manner despite adopting a ductile design philosophy. This paper presents the lessons learned from the observed wall damage in the context of current state of knowledge in the following areas: concentrating longitudinal reinforcement in wall end regions; determining wall thickness to prevent out-of-plane wall buckling; avoiding lap splices in plastic hinge zones; and quantifying minimum vertical reinforcement. http://www.2eceesistanbul.org/
This topic was chosen in response to the devastation caused to Cathedral Square, Christchurch, New Zealand following earthquakes in 2010 and 2011. Working amongst the demolition bought to attention questions about how to re-conceive the square within the rebuilt city. In particular, it raised questions as to how a central square could be better integrated and experienced as a contemporary addition to Christchurch city. This thesis seeks to investigate the ways in which central squares can be better integrated with the contemporary city and how New Urbanist design principles can contribute toward this union. The research principally focuses on the physical and spatial integration of the square with the contemporary city. A drawing-based analysis of select precedent case studies helped to determine early on that overall integration of the contemporary square could be attributed to several interdependent criteria. The detailed studies are supplemented further with literature-based research that narrowed the criteria to five integrative properties. These are: identity, scale and proportion, use, connectivity and natural landscape. These were synthesised, in part, from the integrative New Urbanist movement and the emerging integrative side of the more contemporary Post Urbanist movement. The literature-based research revealed that a more inclusive approach toward New Urbanist and Post Urbanist design methodologies may also produce a more integrated and contemporary square. Three design case studies, using the redesign of Cathedral Square, were undertaken to test this hypothesis. The case studies found that overall, integration was reliant on a harmonious balance between the five integrative properties, concluding that squares can be better integrated with the contemporary city. Further testing of the third concept, which embraced an allied New Urbanist / Post Urbanist approach to design, found that New Urbanism was limited in its contribution toward the integration of the square.
Disasters, either man-made or natural, are characterised by a multiplicity of factors including loss of property, life, environmental degradation, and psychosocial malfunction of the affected community. Although much research has been undertaken on proactive disaster management to help reduce the impacts of natural and man-made disasters, many challenges still remain. In particular, the desire to re-house the affected as quickly as possible can affect long-term recovery if a considered approach is not adopted. Promoting recovery activities, coordination, and information sharing at national and international levels are crucial to avoid duplication. Mannakkara and Wilkinson’s (2014) modified “Build Back Better” (BBB) concept aims for better resilience by incorporating key resilience elements in post-disaster restoration. This research conducted an investigation into the effectiveness of BBB in the recovery process after the 2010–2011 earthquakes in greater Christchurch, New Zealand. The BBB’s impact was assessed in terms of its five key components: built environment, natural environment, social environment, economic environment, and implementation process. This research identified how the modified BBB propositions can assist in disaster risk reduction in the future, and used both qualitative and quantitative data from both the Christchurch and Waimakariri recovery processes. Semi-structured interviews were conducted with key officials from the Christchurch Earthquake Recovery Authority, and city councils, and supplemented by reviewing of the relevant literature. Collecting data from both qualitative and quantitative sources enabled triangulation of the data. The interviewees had directly participated in all phases of the recovery, which helped the researcher gain a clear understanding of the recovery process. The findings led to the identification of best practices from the Christchurch and Waimakariri recovery processes and underlined the effectiveness of the BBB approach for all recovery efforts. This study contributed an assessment tool to aid the measurement of resilience achieved through BBB indicators. This tool provides systematic and structured approach to measure the performance of ongoing recovery.
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The devastating magnitude M6.3 earthquake, that struck the city of Christchurch at 12:51pm on Tuesday 22 February 2011, caused widespread damage to the lifeline systems. Following the event, the Natural Hazard Research Platform (NHRP) of New Zealand funded a short-term project “Recovery of Lifelines” aiming to: 1) coordinate the provision of information to meet lifeline short-term needs; and to 2) facilitate the accessibility to lifelines of best practice engineering details, along with hazards and vulnerability information already available from the local and international scientific community. This paper aims to briefly summarise the management of the recovery process for the most affected lifelines systems, including the electric system, the road, gas, and the water and wastewater networks. Further than this, the paper intends to discuss successes and issues encountered by the “Recovery of Lifelines” NHRP project in supporting lifelines utilities.
The Mw 7.1 Darfield earthquake generated a ~30 km long surface rupture on the Greendale Fault and significant surface deformation related to related blind faults on a previously unrecognized fault system beneath the Canterbury Plains. This earthquake provided the opportunity for research into the patterns and mechanisms of co-seismic and post-seismic crustal deformation. In this thesis I use multiple across-fault EDM surveys, logic trees, surface investigations and deformation feature mapping, seismic reflection surveying, and survey mark (cadastral) re-occupation using GPS to quantify surface displacements at a variety of temporal and spatial scales. My field mapping investigations identified shaking and crustal displacement-induced surface deformation features south and southwest of Christchurch and in the vicinity of the projected surface traces of the Hororata Blind and Charing Cross Faults. The data are consistent with the high peak ground accelerations and broad surface warping due to underlying reverse faulting on the Hororata Blind Fault and Charing Cross Fault. I measured varying amounts of post-seismic displacement at four of five locations that crossed the Greendale Fault. None of the data showed evidence for localized dextral creep on the Greendale Fault surface trace, consistent with other studies showing only minimal regional post-seismic deformation. Instead, the post-seismic deformation field suggests an apparent westward translation of northern parts of the across-fault surveys relative to the southern parts of the surveys that I attribute to post-mainshock creep on blind thrusts and/or other unidentified structures. The seismic surveys identified a deformation zone in the gravels that we attribute to the Hororata Blind Fault but the Charing Cross fault was not able to be identified on the survey. Cadastral re-surveys indicate a deformation field consistent with previously published geodetic data. We use this deformation with regional strain rates to estimate earthquake recurrence intervals of ~7000 to > 14,000 yrs on the Hororata Blind and Charing Cross Faults.
Anyone keeping a global tally of recent disasters is likely to be asking: What role will the hazards and disasters of coastal plains play in the lives and economies of 21st century humanity? In this article, we reflect on this question using examples of how different types of coastal land performed during the Christchurch and other earthquake events to examine the complex of coastal-tectonic hazards that are being constructed in the Tokyo megacity
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This is an interim report from the research study performed within the NHRP Research Project “Impacts of soil liquefaction on land, buildings and buried pipe networks: geotechnical evaluation and design, Project 3: Seismic assessment and design of pipe networks in liquefiable soils”. The work presented herein is a continuation of the comprehensive study on the impacts of Christchurch earthquakes on the buried pipe networks presented in Cubrinovski et al. (2011). This report summarises the performance of Christchurch City’s potable water, waste water and road networks through the 2010-2011 Canterbury Earthquake Sequence (CES), and particularly focuses on the potable water network. It combines evidence based on comprehensive and well-documented data on the damage to the water network, detailed observations and interpretation of liquefaction-induced land damage, records and interpretations of ground motion characteristics induced by the Canterbury earthquakes, for a network analysis and pipeline performance evaluation using a GIS platform. The study addresses a range of issues relevant in the assessment of buried networks in areas affected by strong earthquakes and soil liquefaction. It discusses performance of different pipe materials (modern flexible pipelines and older brittle pipelines) including effects of pipe diameters, fittings and pipeline components/details, trench backfill characteristics, and severity of liquefaction. Detailed breakdown of key factors contributing to the damage to buried pipes is given with reference to the above and other relevant parameters. Particular attention is given to the interpretation, analysis and modelling of liquefaction effects on the damage and performance of the buried pipe networks. Clear link between liquefaction severity and damage rate for the pipeline has been observed with an increasing damage rate seen with increasing liquefaction severity. The approach taken here was to correlate the pipeline damage to LRI (Liquefaction Resistance Index, newly developed parameter in Cubrinovski et al., 2011) which represents a direct measure for the soil resistance to liquefaction while accounting for the seismic demand through PGA. Key quality of the adopted approach is that it provides a general methodology that in conjunction with conventional methods for liquefaction evaluation can be applied elsewhere in New Zealand and internationally. Preliminary correlations between pipeline damage (breaks km-1), liquefaction resistance (LRI) and seismic demand (PGA) have been developed for AC pipes, as an example. Such correlations can be directly used in the design and assessment of pipes in seismic areas both in liquefiable and non-liquefiable areas. Preliminary findings on the key factors for the damage to the potable water pipe network and established empirical correlations are presented including an overview of the damage to the waste water and road networks but with substantially less detail. A comprehensive summary of the damage data on the buried pipelines is given in a series of appendices.
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.
