La pericolosità associata ad un dato fenomeno costituisce uno dei fattori più importanti e difficili da quantificare nelle analisi di rischio, a maggior ragione quando si tratta di fenomeni complessi come nel caso della liquefazione sismica. Il presente lavoro illustra sinteticamente uno studio della pericolosità indotta al suolo da liquefazione basato su un caso campione statistico particolarmente significativo, il terremoto (Mw 6.2) che ha colpito Christchurch, Nuova Zelanda, del 2011. La notevole mole di dati disponibili, relativi alle caratteristiche geotecniche del sottosuolo, unitamente al rilievo dei danni ha consentito innanzitutto di caratterizzare la suscettibilità a liquefazione dell’area, indipendentemente dall’evento sismico, quindi di correlare statisticamente le diverse grandezze e di derivare delle curve di vulnerabilità del suolo.
In this paper, the characteristics of near-fault ground motions recorded during the Mw7.1 Darfield and Mw 6.2 Christchurch earthquakes are examined and compared with existing empirical models. The characteristics of forward-directivity effects are first examined using a wavelet-based pulse-classification algorithm. This is followed by an assessment of the adequacy of empirical models which aim to capture the effect of directivity effects on amplifying the acceleration response spectra; and the period and peak velocity of the forward-directivity pulse. It is illustrated that broadband directivity models developed by Somerville et al. (1997) and Abrahamson (2000) generally under-predict the observed amplification of response spectral ordinates at longer vibration periods. In contrast, a recently developed narrowband model by Shahi and Baker (2011) provides significantly improved predictions by amplifying the response spectra within a small range of periods surrounding the directivity pulse period. Although the empirical predictions of the pulse period are generally favourable for the Christchurch earthquake, the observations from the Darfield earthquake are significantly under-predicted. The elongation in observed pulse periods is inferred as being a result of the soft sedimentary soils of the Canterbury basin. However, empirical predictions of the observed peak velocity associated with the directivity pulse are generally adequate for both events.
In 2010 and 2011, Aotearoa New Zealand was hit by a number of major disasters involving loss of human life and severe disruption to social, ecological and economic wellbeing. The Pike River mine explosions were closely followed by a sequence of major earthquakes in Christchurch, seismic events that have permanently altered the lives of thousands of people in our third largest city, the closure of the central business district and the effective abandonment of whole residential areas. In early October 2011, the ship, Rena, grounded on a reef off the port of Tauranga and threatened a major oil spill throughout the Bay of Plenty, where local communities with spiritual and cultural connections to the land depend on sea food as well as thrive on tourism. The Council for Social Work Education Aotearoa New Zealand (CSWEANZ), representing all the Schools of Social Work in New Zealand, held a ‘Disaster Curriculum’ day in November 2011, at which social workers and Civil Defence leaders involved in the Christchurch earthquakes, the Rena Disaster, Fiji floods and the Boxing Day tsunami presented their narrative experience of disaster response and recovery. Workshops discussed and identified core elements that participants considered vital to a social work curriculum that would enable social work graduates in a range of community and cultural settings to respond in safe, creative and informed ways. We present our core ideas for a social work disaster curriculum and consider a wide range of educational content based on existing knowledge bases and new content within a disaster framework. http://www.swsd-stockholm-2012.org/
This paper concerns the explicit consideration of near-fault directivity in conventional ground motion prediction models, and its implication for probabilistic seismic hazard analysis (PSHA) in New Zealand. The proposed approach utilises recently developed models by Shahi & Baker (2011), which account for both the 'narrowband' nature of the directivity pulse on spectral ordinates, and the probability of pulse occurrence at the site of interest. Furthermore, in order to correctly consider directivity, distributed seismicity sources are considered as finite-faults, as opposed to their (incorrect) conventional treatment as point-sources. The significance of directivity on hazard analysis results is illustrated for various vibration periods at generic sites located in Christchurch and Otira, two locations whose seismic hazard is comprised of notably different seismic sources. When compared to the PSHA results considering directivity and distributed seismicity as finite faults, it is shown that the NZS1170.5:2004 directivity factor is notably unconservative for all vibration periods in Otira (i.e. high seismic hazard region); and unconservative for Christchurch at short-to-moderate vibration periods ( < 3s); but conservative at long periods ( > 4s).
Nel presente articolo si illustra una procedura per il processamento automatizzato di prove CPT, il calcolo di vari indici di liquefazione e la rappresentazione dei dati su mappa. La procedura è applicata al caso studio del terremoto di Christchurch, Nuova Zelanda, del 22 febbraio 2011 (magnitudo momento, Mw = 6.2). Dall’analisi spaziale dei risultati emerge una buona correlazione tra le mappe ottenute per l’indicatore degli effetti al suolo e i danni osservati (su terreni e strutture). Tuttavia, per confermare la validità di tale procedura, sarà necessario esaminare ulteriori casi studio nel mondo.
This paper explores the responses by a group of children to an art project that was undertaken by a small school in New Zealand after the September 2010 and February 2011 Christchurch earthquakes. Undertaken over a period of two years, the project aimed to find a suitable form of memorialising this significant event in a way that was appropriate and meaningful to the community. Alongside images that related directly to the event of the earthquakes, the art form of a mosaic was chosen, and consisted of images and symbols that clearly drew on the hopes and dreams of a school community who were refusing to be defined by the disaster. The paper 'writes' the mosaic by placing fragments of speech spoken by the children involved in relation to ideas about memory, affect, and the 'sublime', through the work of Jean-Francois Lyotard. The paper explores the mosaic as constituted by the literal and metaphorical 'broken pieces' of the city of Christchurch in ways that confer pedagogic value inscribed through the creation of a public art space by children. AM - Accepted Manuscript
This thesis is about many things, not least of all the September 4th 2010 and February 22nd 2011 earthquakes that shook Christchurch, New Zealand. A city was shaken, events which worked to lay open the normally invisible yet vital objects, processes and technologies which are the focus of inquiry: the sewers, pipes, pumps, the digital technologies, the land and politics which constitute the Christchurch wastewater networks. The thesis is an eclectic mix drawing together methods and concepts from Bruno Latour, John Law, Giles Deleuze and Felix Guattari, Nigel Thrift, Donna Haraway and Patrick Joyce. It is an exploration of how the technologies and objects of sanitation perform the city, and how such things which are normally hidden and obscured, are made visible. The question of visibility is also turned toward the research itself: how does one observe, and describe? How are sociological visibilities constructed? Through the research, the encountering of objects in the field, the processes of method, the pedagogy of concepts, and the construction of risk, the thesis comes to be understood as a particular kind of social scientific artefact which assembles four different accounts: the first regards the construction of visibility; the second explores Christchurch city from the control room where the urban sanitary infrastructures are monitored; the third chapter looks at the formatted and embodied practices which emerge with the correlation of the city and sanitation; the fourth looks at the changing politics of a city grappling with severely damaged essential services, land and structures. The final chapter considers how the differences between romantic and baroque sensibilities mean that these four accounts elicit knowing not through smoothness or uniformity, but in partiality and non-coherence. This thesis is about pipes, pump stations, and treatment plants; about the effluent of a city; about the messiness of social science when confronted by the equally messy world of wastewater.
Tertiary students, not just working populations, might be experiencing feelings of burnout following the Christchurch earthquakes of 2010 and 2011. In the aftermath of a major disaster, the gap between the resources available to handle pressures (e.g., support) and the demands inherent in the pursuit of an academic degree (e.g., heavy workload) may lead to feelings of burnout among students. This study hypothesised that burnout dimensions (emotional exhaustion and disengagement) would be related to students’ perceptions of immediate institutional support, extended institutional support, peer support, family support, and work overload. Additionally, it was proposed that institutional and social support would moderate the relationship between work overload and burnout. Two hundred and seventy one third and fourth year students were sampled using an online questionnaire. These particular students were expected to be at greater risk of emotional exhaustion and academic disengagement because they were at the earliest stage of their tertiary education when the major earthquakes first hit. Family support and extended institutional support were found to be associated with decreased levels of emotional exhaustion and disengagement. Meanwhile, work overload was found to be related to increased levels of emotional exhaustion and disengagement. Furthermore, both peer support and immediate institutional support were found to have a moderating effect on the relationship between work overload and disengagement. This study has exposed unique findings which contribute to burnout research especially in a post-disaster context, and raises the importance of providing the right types of support for individuals who are particularly dealing with the consequences of a natural disaster.
Two projects are documented within this MEM Report: I. The first project examined what was learnt involving the critical infrastructure in the aftermath of natural disasters in the Canterbury region of New Zealand – the most prominent being the series of earthquakes between 2010 and 2011. The project identified several learning gaps, leading to recommendations for further investigations that could add significant value for the lifeline infrastructure community. II. Following the Lifeline Lesson Learnt Project, the Disaster Mitigation Guideline series was initiated with two booklets, one on Emergency Potable Water and a second on Emergency Sanitation. The key message from both projects is that we can and must learn from disasters. The projects described are part of the emergency management, and critical infrastructure learning cycles – presenting knowledge captured by others in a digestible format, enabling the lessons to be reapplied. Without these kinds of projects, there will be fewer opportunities to learn from other’s successes and failures when it comes to preparing for natural disasters.
As a consequence of the 2010 – 2011 Canterbury earthquake sequence, Christchurch experienced widespread liquefaction, vertical settlement and lateral spreading. These geological processes caused extensive damage to both housing and infrastructure, and increased the need for geotechnical investigation substantially. Cone Penetration Testing (CPT) has become the most common method for liquefaction assessment in Christchurch, and issues have been identified with the soil behaviour type, liquefaction potential and vertical settlement estimates, particularly in the north-western suburbs of Christchurch where soils consist mostly of silts, clayey silts and silty clays. The CPT soil behaviour type often appears to over-estimate the fines content within a soil, while the liquefaction potential and vertical settlement are often calculated higher than those measured after the Canterbury earthquake sequence. To investigate these issues, laboratory work was carried out on three adjacent CPT/borehole pairs from the Groynes Park subdivision in northern Christchurch. Boreholes were logged according to NZGS standards, separated into stratigraphic layers, and laboratory tests were conducted on representative samples. Comparison of these results with the CPT soil behaviour types provided valuable information, where 62% of soils on average were specified by the CPT at the Groynes Park subdivision as finer than what was actually present, 20% of soils on average were specified as coarser than what was actually present, and only 18% of soils on average were correctly classified by the CPT. Hence the CPT soil behaviour type is not accurately describing the stratigraphic profile at the Groynes Park subdivision, and it is understood that this is also the case in much of northwest Christchurch where similar soils are found. The computer software CLiq, by GeoLogismiki, uses assessment parameter constants which are able to be adjusted with each CPT file, in an attempt to make each more accurate. These parameter changes can in some cases substantially alter the results for liquefaction analysis. The sensitivity of the overall assessment method, raising and lowering the water table, lowering the soil behaviour type index, Ic, liquefaction cutoff value, the layer detection option, and the weighting factor option, were analysed by comparison with a set of ‘base settings’. The investigation confirmed that liquefaction analysis results can be very sensitive to the parameters selected, and demonstrated the dependency of the soil behaviour type on the soil behaviour type index, as the tested assessment parameters made very little to no changes to the soil behaviour type plots. The soil behaviour type index, Ic, developed by Robertson and Wride (1998) has been used to define a soil’s behaviour type, which is defined according to a set of numerical boundaries. In addition to this, the liquefaction cutoff point is defined as Ic > 2.6, whereby it is assumed that any soils with an Ic value above this will not liquefy due to clay-like tendencies (Robertson and Wride, 1998). The method has been identified in this thesis as being potentially unsuitable for some areas of Christchurch as it was developed for mostly sandy soils. An alternative methodology involving adjustment of the Robertson and Wride (1998) soil behaviour type boundaries is proposed as follows: Ic < 1.31 – Gravelly sand to dense sand 1.31 < Ic < 1.90 – Sands: clean sand to silty sand 1.90 < Ic < 2.50 – Sand mixtures: silty sand to sandy silt 2.50 < Ic < 3.20 – Silt mixtures: clayey silt to silty clay 3.20 < Ic < 3.60 – Clays: silty clay to clay Ic > 3.60 – Organics soils: peats. When the soil behaviour type boundary changes were applied to 15 test sites throughout Christchurch, 67% showed an improved change of soil behaviour type, while the remaining 33% remained unchanged, because they consisted almost entirely of sand. Within these boundary changes, the liquefaction cutoff point was moved from Ic > 2.6 to Ic > 2.5 and altered the liquefaction potential and vertical settlement to more realistic ii values. This confirmed that the overall soil behaviour type boundary changes appear to solve both the soil behaviour type issues and reduce the overestimation of liquefaction potential and vertical settlement. This thesis acts as a starting point towards researching the issues discussed. In particular, future work which would be useful includes investigation of the CLiq assessment parameter adjustments, and those which would be most suitable for use in clay-rich soils such as those in Christchurch. In particular consideration of how the water table can be better assessed when perched layers of water exist, with the limitation that only one elevation can be entered into CLiq. Additionally, a useful investigation would be a comparison of the known liquefaction and settlements from the Canterbury earthquake sequence with the liquefaction and settlement potentials calculated in CLiq for equivalent shaking conditions. This would enable the difference between the two to be accurately defined, and a suitable adjustment applied. Finally, inconsistencies between the Laser-Sizer and Hydrometer should be investigated, as the Laser-Sizer under-estimated the fines content by up to one third of the Hydrometer values.
In September 2010 and February 2011 the Canterbury region of New Zealand was struck by two powerful earthquakes, registering magnitude 7.1 and 6.3 respectively on the Richter scale. The second earthquake was centred 10 kilometres south-east of the centre of Christchurch (the region’s capital and New Zealand’s third most populous urban area, with approximately 360,000 residents) at a depth of five kilometres. 185 people were killed, making it the second deadliest natural disaster in New Zealand’s history. (66 people were killed in the collapse of one building alone, the six-storey Canterbury Television building.) The earthquake occurred during the lunch hour, increasing the number of people killed on footpaths and in buses and cars by falling debris. In addition to the loss of life, the earthquake caused catastrophic damage to both land and buildings in Christchurch, particularly in the central business district. Many commercial and residential buildings collapsed in the tremors; others were damaged through soil liquefaction and surface flooding. Over 1,000 buildings in the central business district were eventually demolished because of safety concerns, and an estimated 70,000 people had to leave the city after the earthquakes because their homes were uninhabitable. The New Zealand Government declared a state of national emergency, which stayed in force for ten weeks. In 2014 the Government estimated that the rebuild process would cost NZ$40 billion (approximately US$27.3 billion, a cost equivalent to 17% of New Zealand’s annual GDP). Economists now estimate it could take the New Zealand economy between 50 and 100 years to recover. The earthquakes generated tens of thousands of insurance claims, both against private home insurance companies and against the New Zealand Earthquake Commission, a government-owned statutory body which provides primary natural disaster insurance to residential property owners in New Zealand. These ranged from claims for hundreds of millions of dollars concerning the local port and university to much smaller claims in respect of the thousands of residential homes damaged. Many of these insurance claims resulted in civil proceedings, caused by disputes about policy cover, the extent of the damage and the cost and/or methodology of repairs, as well as failures in communication and delays caused by the overwhelming number of claims. Disputes were complicated by the fact that the Earthquake Commission provides primary insurance cover up to a monetary cap, with any additional costs to be met by the property owner’s private insurer. Litigation funders and non-lawyer claims advocates who took a percentage of any insurance proceeds also soon became involved. These two factors increased the number of parties involved in any given claim and introduced further obstacles to resolution. Resolving these disputes both efficiently and fairly was (and remains) central to the rebuild process. This created an unprecedented challenge for the justice system in Christchurch (and New Zealand), exacerbated by the fact that the Christchurch High Court building was itself damaged in the earthquakes, with the Court having to relocate to temporary premises. (The High Court hears civil claims exceeding NZ$200,000 in value (approximately US$140,000) or those involving particularly complex issues. Most of the claims fell into this category.) This paper will examine the response of the Christchurch High Court to this extraordinary situation as a case study in innovative judging practices and from a jurisprudential perspective. In 2011, following the earthquakes, the High Court made a commitment that earthquake-related civil claims would be dealt with as swiftly as the Court's resources permitted. In May 2012, it commenced a special “Earthquake List” to manage these cases. The list (which is ongoing) seeks to streamline the trial process, resolve quickly claims with precedent value or involving acute personal hardship or large numbers of people, facilitate settlement and generally work proactively and innovatively with local lawyers, technical experts and other stakeholders. For example, the Court maintains a public list (in spreadsheet format, available online) with details of all active cases before the Court, listing the parties and their lawyers, summarising the facts and identifying the legal issues raised. It identifies cases in which issues of general importance have been or will be decided, with the expressed purpose being to assist earthquake litigants and those contemplating litigation and to facilitate communication among parties and lawyers. This paper will posit the Earthquake List as an attempt to implement innovative judging techniques to provide efficient yet just legal processes, and which can be examined from a variety of jurisprudential perspectives. One of these is as a case study in the well-established debate about the dialogic relationship between public decisions and private settlement in the rule of law. Drawing on the work of scholars such as Hazel Genn, Owen Fiss, David Luban, Carrie Menkel-Meadow and Judith Resnik, it will explore the tension between the need to develop the law through the doctrine of precedent and the need to resolve civil disputes fairly, affordably and expeditiously. It will also be informed by the presenter’s personal experience of the interplay between reported decisions and private settlement in post-earthquake Christchurch through her work mediating insurance disputes. From a methodological perspective, this research project itself gives rise to issues suitable for discussion at the Law and Society Annual Meeting. These include the challenges in empirical study of judges, working with data collected by the courts and statistical analysis of the legal process in reference to settlement. September 2015 marked the five-year anniversary of the first Christchurch earthquake. There remains widespread dissatisfaction amongst Christchurch residents with the ongoing delays in resolving claims, particularly insurers, and the rebuild process. There will continue to be challenges in Christchurch for years to come, both from as-yet unresolved claims but also because of the possibility of a new wave of claims arising from poor quality repairs. Thus, a final purpose of presenting this paper at the 2016 Meeting is to gain the benefit of other scholarly perspectives and experiences of innovative judging best practice, with a view to strengthening and improving the judicial processes in Christchurch. This Annual Meeting of the Law and Society Association in New Orleans is a particularly appropriate forum for this paper, given the recent ten year anniversary of Hurricane Katrina and the plenary session theme of “Natural and Unnatural Disasters – human crises and law’s response.” The presenter has a personal connection with this theme, as she was a Fulbright scholar from New Zealand at New York University in 2005/2006 and participated in the student volunteer cleanup effort in New Orleans following Katrina. http://www.lawandsociety.org/NewOrleans2016/docs/2016_Program.pdf
Social media have changed disaster response and recovery in the way people inform themselves, provide community support and make sense of unfolding and past events online. During the Canterbury earthquakes of 2010 and 2011 social media platforms such as Facebook and Twitter became part of the story of the quakes in the region, as well as a basis for ongoing public engagement during the rebuild efforts in Christchurch. While a variety of research has been conducted on the use of social media in disaster situations (Bruns & Burgess, 2012; Potts, Seitzinger, Jones, & Harrison, 2011; Shklovski, Palen, & Sutton, 2008), studies about their uses in long-term disaster recovery and across different platforms are underrepresented. This research analyses networked practices of sensemaking around the Canterbury earthquakes over the course of disaster response, recovery and rebuild, focussing on Facebook and Twitter. Following a mixed methodological design data was gathered in interviews with people who started local Facebook pages, and through digital media methods of data collection and computational analysis of public Facebook pages and a historical Twitter dataset gathered around eight different earthquake-related events between 2010 and 2013. Data is further analysed through discursive and narrative tools of inquiry. This research sheds light on communication practices in the drawn-out process of disaster recovery on the ground in connecting different modes of discourse. Examining the ongoing negotiation of networked identities through technologically mediated social practices during Canterbury’s rebuild, the connection between online environments and the city of Christchurch, as a physical place, is unpacked. This research subsequently develops a new methodology to study social media platforms and provide new and detailed information on both the communication practices in issue-based online publics and the ongoing negotiation of the impact of the Canterbury earthquakes through networked digital means.
Following the Mw 6.2 Christchurch Earthquake on 22 February 2011, extensive ground cracking in loessial soils was reported in some areas of the Port Hills, southeast of central Christchurch. This study was undertaken to investigate the mechanisms of earthquake-induced ground damage on the eastern side of the Hillsborough Valley. A zone of extensional cracking up to 40m wide and 600m long was identified along the eastern foot-slope, accompanied by compression features and spring formation at the toe of the slope. An engineering geological and geomorphological model was developed for the eastern Hillsborough Valley that incorporates geotechnical investigation data sourced from the Canterbury Geotechnical Database (CGD), the findings of trenching and seismic refraction surveying carried out for this research, and interpretation of historical aerial photographs. The thickness and extent of a buried peat swamp at the base of the slope was mapped, and found to coincide with significant compression features. Ground cracking was found to have occurred entirely within loess-colluvium and to follow the apices of pre-1920s tunnel-gully fan debris at the southern end of the valley. The ground-cracking on the eastern side of the Hillsborough Valley is interpreted to have formed through tensile failure of the loess-colluvium. Testing was carried out to determine the tensile strength of Port Hills loess colluvium as a function of water content and density, in order to better understand the occurrence and distribution of the observed ground cracking. A comprehensive review of the soil tensile strength testing literature was undertaken, from which a test methodology was developed. Results show remoulded loess-colluvium to possess tensile strength of 7 - 28 kPa across the range of tested moisture contents (10-15%) and dry densities (1650-1900kg/m3). A positive linear relationship was observed between tensile strength and dry density, and a negative linear relationship between moisture content and tensile strength. The observed ground damage and available geotechnical information (inclinometer and piezometer records provided by the Earthquake Commission) were together used to interpret the mechanism(s) of slope movement that occurred in the eastern Hillsborough Valley. The observed ground damage is characteristic of translational movement, but without the development of lateral release scarps, or a basal sliding surface - which was not located during drilling. It is hypothesised that shear displacement has been accommodated by multiple slip surfaces of limited extent within the upper 10m of the slope. Movement has likely occurred within near-saturated colluvial units that have lost strength during earthquake shaking. The eastern Hillsborough Valley is considered to be an ‘incipient translational slide’, as both the patterns of damage and shearing are consistent with the early stages of such slide development. Sliding block analysis was utilised to understand how the eastern Hillsborough Valley may perform in a future large magnitude earthquake. Known cumulative displacements of ~0.3m for eastern Hillsborough Valley during the 2010-2011 Canterbury Earthquake Sequence were compared with modelled slope displacements to back-analyse a lower-bound yield acceleration of 0.2 - 0.25g. Synthetic broadband modelling for future Alpine and Hope Fault earthquakes indicates PGAs of approximately 0.08g for soil sites in the Christchurch area, as such, slope movement is unlikely to be reactivated by an Alpine Fault or Hope Fault earthquake. This does not take into account the possible role of strength loss due to excess pore pressure that may occur during these future events.
Data from the 2010-2011 Canterbury earthquake sequence (CES) provides an unprecedented opportunity to assess and advance the current state of practice for evaluating liquefaction triggering. Towards this end, select case histories from the CES are used herein to assess the predictive capabilities of three alternative CPT-based simplified liquefaction evaluation procedures: Robertson and Wride (1998); Moss et al. (2006); and Idriss and Boulanger (2008). Additionally, the Liquefaction Potential Index (LPI) framework for predicting the severity of surficial liquefaction manifestations is also used to assess the predictive capabilities of the liquefaction evaluation procedures. Although it is not without limitations, use of the LPI framework for this purpose circumvents the need for selecting “critical” layers and their representative properties for study sites, which inherently involves subjectivity and thus has been a point of contention among researchers. It was found that while all the assessed liquefaction triggering evaluation procedures performed well for the parameter ranges of the sites analyzed, the procedure proposed by Idriss and Boulanger (2008) yielded predictions that are more consistent with field observations than the other procedures. However, use of the Idriss and Boulanger (2008) procedure in conjunction with a Christchurch-specific correlation to estimate fines content showed a decreased performance relative to using a generic fines content correlation. As a result, the fines correction for the Idriss and Boulanger (2008) procedure needs further study.
This study uses 44 high quality liquefaction case histories taken from 22 locations affected by the 2010-2011 Canterbury earthquake sequence to evaluate four commonly used CPT-VS correlations (i.e., Robertson, 2009; Hegazy and Mayne, 2006; Andrus et al., 2007; McGann et al., 2015b). Co-located CPT soundings and VS profiles, developed from surface wave testing, were obtained at 22 locations and case histories were developed for the Mw 7.1, 4 September 2010 Darfield and Mw 6.2, 22 February 2011 Christchurch earthquakes. The CPT soundings are used to generate VS profiles using each of four CPT-VS correlations. These correlated VS profiles are used to estimate the factor of safety against liquefaction using the Kayen et al. (2013) VS-based simplified liquefaction evaluation procedure. An error index is used to quantify the predictive capabilities of these correlations in relation to the observations of liquefaction (or the lack thereof). Additionally, the error indices from the CPT-correlated VS profiles are compared to those obtained using: (1) the Kayen et al. (2013) procedure with surface wave-derived VS profiles, and (2) the Idriss and Boulanger (2008) CPT-based liquefaction evaluation procedure. Based on the error indices, the evaluation procedures based on direct measurements of either CPT or VS provided more accurate liquefaction triggering estimates than those obtained from any of the CPT-VS correlations. However, the performance of the CPT-VS correlations varied, with the Robertson (2009) and Hegazy and Mayne (2006) correlations performing relatively poorly for the Christchurch soils and the Andrus et al. (2007) and McGann et al. (2015b) correlations performing better. The McGann et al. (2015b) correlation had the lowest error indices of the CPT-VS correlations tested, however, none of the CPT-VS correlations provided accurate enough VS predictions to be used for the evaluation of liquefaction triggering using the VS-based liquefaction evaluation procedures.
Seismic retrofitting of unreinforced masonry buildings using posttensioning has been the topic of many recent experimental research projects. However, the performance of such retrofit designs in actual design level earthquakes has previously been poorly documented. In 1984 two stone masonry buildings within The Arts Centre of Christchurch received posttensioned seismic retrofits, which were subsequently subjected to design level seismic loads during the 2010/2011 Canterbury earthquake sequence. These 26 year old retrofits were part of a global scheme to strengthen and secure the historic building complex and were subject to considerable budgetary constraints. Given the limited resources available at the time of construction and the current degraded state of the steel posttension tendons, the posttensioned retrofits performed well in preventing major damage to the overall structure of the two buildings in the Canterbury earthquakes. When compared to other similar unretrofitted structures within The Arts Centre, it is demonstrated that the posttensioning significantly improved the in-plane and out-of-plane wall strength and the ability to limit residual wall displacements. The history of The Arts Centre buildings and the details of the Canterbury earthquakes is discussed, followed by examination of the performance of the posttension retrofits and the suitability of this technique for future retrofitting of other historic unreinforced masonry buildings. http://www.aees.org.au/downloads/conference-papers/
This article argues that active coordination of research engagement after disasters has the potential to maximize research opportunities, improve research quality, increase end-user engagement, and manage escalating research activity to mitigate ethical risks posed to impacted populations. The focus is on the coordination of research activity after the 22nd February 2011 Mw6.2 Christchurch earthquake by the then newly-formed national research consortium, the Natural Hazards Research Platform, which included a social science research moratorium during the declared state of national emergency. Decisions defining this organisation’s functional and structural parameters are analyzed to identify lessons concerning the need for systematic approaches to the management of post disaster research, in collaboration with the response effort. Other lessons include the importance of involving an existing, broadly-based research consortium, ensuring that this consortium's coordination role is fully integrated into emergency management structures, and ensuring that all aspects of decision-making processes are transparent and easily accessed.
New Zealand lies on the Pacific Ring of Fire – the belt of vulnerable, unpredictable fault lines which are the primary cause for earthquakes in this country. Most recently, as evident in the aftermath of the 2011 Christchurch earthquake -the destruction of the city centre led to the emergence of sub centres in different parts of the city each with different, desperate needs. The lack of preparedness in the wake of an earthquake hence, exacerbated this destitution. This research explores architecture’s role in the sub-centre. How can architecture facilitate resilience through this decentralised typology? The design-led approach critiques the implications of architecture as a tool for resilience whilst highlighting the desperate need for the engagement of architecture in planning before a disaster strikes. The resulting response explores resilience through an architectural lens that has a wider infrastructural, contextual and user-focussed need.
This report presents the simplified seismic assessment of a case study reinforced concrete (RC) building following the newly developed and refined NZSEE/MBIE guidelines on seismic assessment (NZSEE/MBIE, semi-final draft 26 October 2016). After an overview of the step-by-step ‘diagnostic’ process, including an holistic and qualitative description of the expected vulnerabilities and of the assessment strategy/methodology, focus is given, whilst not limited, to the implementation of a Detailed Seismic Assessment (DSA) (NZSEE/MBIE, 2016c). The DSA is intended to provide a more reliable and consistent outcome than what can be provided by an initial seismic assessment (ISA). In fact, while the Initial Seismic Assessment (ISA), of which the Initial Evaluation Procedure is only a part of, is the more natural and still recommended first step in the overall assessment process, it is mostly intended to be a coarse evaluation involving as few resources as reasonably possible. It is thus expected that an ISA will be followed by a Detailed Seismic Assessment (DSA) not only where the threshold of 33%NBS is not achieved but also where important decisions are intended that are reliant on the seismic status of the building. The use of %NBS (% New Building Standard) as a capacity/demand ratio to describe the result of the seismic assessment at all levels of assessment procedure (ISA through to DSA) is deliberate by the NZSEE/MBIE guidelines (Part A) (NZSEE/MBIE 2016a). The rating for the building needs only be based on the lowest level of assessment that is warranted for the particular circumstances. Discussion on how the %NBS rating is to be determined can be found in Section A3.3 (NZSEE/MBIE 2016a), and, more specifically, in Part B for the ISA (NZSEE/MBIE 2016b) and Part C for the DSA (NZSEE/MBIE 2016c). As per other international approaches, the DSA can be based on several analysis procedures to assess the structural behaviour (linear, nonlinear, static or dynamic, force or displacement-based). The significantly revamped NZSEE 2016 Seismic Assessment Guidelines strongly recommend the use of an analytical (basically ‘by hand’) method, referred to the Simple Lateral Mechanism Analysis (SLaMA) as a first phase of any other numerically-based analysis method. Significant effort has thus been dedicated to provide within the NZSEE 2016 guidelines (NZSEE/MBIE 2016c) a step-by-step description of the procedure, either in general terms (Chapter 2) or with specific reference to Reinforced Concrete Buildings (Chapter 5). More specifically, extract from the guidelines, NZSEE “recommend using the Simple Lateral Mechanism Analysis (SLaMA) procedure as a first step in any assessment. While SLaMA is essentially an analysis technique, it enables assessors to investigate (and present in a simple form) the potential contribution and interaction of a number of structural elements and their likely effect on the building’s global capacity. In some cases, the results of a SLaMA will only be indicative. However, it is expected that its use should help assessors achieve a more reliable outcome than if they only carried out a detailed analysis, especially if that analysis is limited to the elastic range For complex structural systems, a 3D dynamic analysis may be necessary to supplement the simplified nonlinear Simple Lateral Mechanism Analysis (SLaMA).” This report presents the development of a full design example for the the implementation of the SLaMA method on a case study buildings and a validation/comparison with a non-linear static (pushover) analysis. The step-by-step-procedure, summarized in Figure 1, will be herein demonstrated from a component level (beams, columns, wall elements) to a subassembly level (hierarchy of strength in a beam-column joint) and to a system level (frame, C-Wall) assuming initially a 2D behaviour of the key structural system, and then incorporating a by-hand 3D behaviour (torsional effects).
Following a natural disaster, children are prone to various reactions and maladaptive responses as a result of exposure to a highly stressful and potentially traumatic event. Children’s responses can range from an acute stress response to post-traumatic-stress disorder or may fall somewhere in between. While responses to highly stressful events vary, a common finding is that children will develop sleep problems. This was found following the Christchurch September 2010 and February 2011 earthquakes. The purpose of this study was to investigate the context and phenomenology of the sleep problems of a small number of children experiencing these and the 2016 Kaikoura earthquakes, including possible mechanisms of effect. Participants were four families, including four mothers, one father and four children. The design of this study was unique. Interview data was subjected to a content analysis, extracted themes were organised according to an ecological-transactional framework and then the factors were subject to an analysis, based on the principles of clinical reasoning, in order to identify possible mechanisms of effect. Parents reported 16 different sleep problems across children, as well as other behaviours possibly indicative of post-traumatic stress response. In total, 34 themes and 26 interactions were extracted in relation to factors identified across participants about the children’s sleep and the families’ earthquake experiences. This demonstrated how complex it is to explore the development of sleep problems in the context of disaster. Key factors identified by parents that likely played a key role in the development and perpetuation of sleep problems included earthquake related anxiety, parental mental health and conflict, the child’s emotional and behavioural problems and other negative life events following the earthquakes. The clinical implications of the analysis included being aware that such families, may not have had access to specialized support around their children’s sleep. This was much needed due to the strain such problems place on the family, especially in a post-disaster community such as Christchurch.
The 2010-2011 Christchurch earthquakes generated damage in several Reinforced Concrete (RC) buildings, which had RC walls as the principal resistant element against earthquake demand. Despite the agreement between structural engineers and researchers in an overall successfully performance there was a lack of knowledge about the behaviour of the damaged structures, and even deeper about a repaired structure, which triggers arguments between different parties that remains up to these days. Then, it is necessary to understand the capacity of the buildings after the earthquake and see how simple repairs techniques improve the building performance. This study will assess the residual capacity of ductile slender RC walls according to current standards in New Zealand, NZS 3101.1 2006 A3. First, a Repaired RC walls Database is created trying to gather previous studies and to evaluate them with existing international guidelines. Then, an archetype building is designed, and the wall is extracted and scaled. Four half-scale walls were designed and will be constructed and tested at the Structures Testing Laboratory at The University of Auckland. The overall dimensions are 3 [m] height, 2 [m] length and 0.175 [m] thick. All four walls will be identical, with differences in the loading protocol and the presence or absence of a repair technique. Results are going to be useful to assess the residual capacity of a damaged wall compare to the original behaviour and also the repaired capacity of walls with simpler repair techniques. The expected behaviour is focussed on big changes in stiffness, more evident than in previously tested RC beams found in the literature.
During the Christchurch earthquake of February 2011, several midrise reinforced concrete masonry (RCM) buildings showed performance levels that fall in the range of life safety to near collapse. A case study of one of these buildings, a six-story RCM building deemed to have reached the near collapse performance level, is presented in this paper. The RCM walls on the second floor failed due to toe crushing, reducing the building's lateral resistance in the east–west direction. A three-dimensional (3-D) nonlinear dynamic analysis was conducted to simulate the development of the governing failure mechanism. Analysis results showed that the walls that were damaged were subjected to large compression loads during the earthquake, which caused an increase in their in-plane lateral strength but reduced their ductility capacity. After toe crushing failure, axial instability of the model was prevented by a redistribution of gravity loads. VoR - Version of Record
INTRODUCTION: There is little research on the role of creative arts and craft in disaster recovery. This article reports findings about the emergent role of crafting from research conducted after the 2010–2011 series of earthquakes in Christchurch and surrounding districts in Aotearoa New Zealand. In particular, the article focuses on the significance and differing interpretations of the notion of place expressed by participants through their craftwork, in this case led by women and mediated by the post-earthquake geographic and temporal context. METHOD: This qualitative research included nine individual interviews and five focus group interviews with crafters from Christchurch and surrounding districts. There were 35 participants in total, 33 were women. Applied thematic analysis was used to code the data and identify themes. These themes included connection to place, the symbolism of craft, the healing experience of craft groups and places for women. The notion of place was evident across all three themes. FINDINGS: The findings from the research demonstrate differing ways in which the significance of place was reflected in the craftwork. Participants interpreted the concept of place in descriptive, symbolic, and therapeutic ways. IMPLICATIONS: More understanding about the way creative endeavours like crafting can be used to help ameliorate the impact of natural disasters is needed. Social work practitioners are encouraged to explore place-based wellbeing during their work with service users and to include aspects of artistry, craft and creativity.
Natural catastrophes are increasing worldwide. They are becoming more frequent but also more severe and impactful on our built environment leading to extensive damage and losses. Earthquake events account for the smallest part of natural events; nevertheless seismic damage led to the most fatalities and significant losses over the period 1981-2016 (Munich Re). Damage prediction is helpful for emergency management and the development of earthquake risk mitigation projects. Recent design efforts focused on the application of performance-based design engineering where damage estimation methodologies use fragility and vulnerability functions. However, the approach does not explicitly specify the essential criteria leading to economic losses. There is thus a need for an improved methodology that finds the critical building elements related to significant losses. The here presented methodology uses data science techniques to identify key building features that contribute to the bulk of losses. It uses empirical data collected on site during earthquake reconnaissance mission to train a machine learning model that can further be used for the estimation of building damage post-earthquake. The first model is developed for Christchurch. Empirical building damage data from the 2010-2011 earthquake events is analysed to find the building features that contributed the most to damage. Once processed, the data is used to train a machine-learning model that can be applied to estimate losses in future earthquake events.
The connections between walls of unreinforced masonry (URM) buildings and flexible timber diaphragms are critical building components that must perform adequately before desirable earthquake response of URM buildings may be achieved. Field observations made during the initial reconnaissance and the subsequent damage surveys of clay brick URM buildings following the 2010/2011 Canterbury, New Zealand earthquakes revealed numerous cases where anchor connections joining masonry walls or parapets with roof or floor diaphragms appeared to have failed prematurely. These observations were more frequent for adhesive anchor connections than for through-bolt connections (i.e. anchorages having plates on the exterior façade of the masonry walls). Subsequently, an in-field test program was undertaken in an attempt to evaluate the performance of adhesive anchor connections between unreinforced clay brick URM walls and roof or floor diaphragm. The study consisted of a total of almost 400 anchor tests conducted in eleven existing URM buildings located in Christchurch, Whanganui and Auckland. Specific objectives of the study included the identification of failure modes of adhesive anchors in existing URM walls and the influence of the following variables on anchor load-displacement response: adhesive type, strength of the masonry materials (brick and mortar), anchor embedment depth, anchor rod diameter, overburden level, anchor rod type, quality of installation and the use of metal mesh sleeve. In addition, the comparative performance of bent anchors (installed at an angle of minimum 22.5o to the perpendicular projection from the wall surface) and anchors positioned horizontally was investigated. Observations on the performance of wall-to-diaphragm connections in the 2010/2011 Canterbury earthquakes, a snapshot of the performed experimental program and the test results and a preliminary proposed pull-out capacity of adhesive anchors are presented herein. http://www.confer.co.nz/nzsee/ VoR - Version of Record
©2019. American Geophysical Union. All Rights Reserved. Earthquakes have been inferred to induce hydrological changes in aquifers on the basis of either changes to well water-levels or tidal behavior, but the relationship between these changes remains unclear. Here, changes in tidal behavior and water-levels are quantified using a hydrological network monitoring gravel aquifers in Canterbury, New Zealand, in response to nine earthquakes (of magnitudes M w 5.4 to 7.8) that occurred between 2008 and 2015. Of the 161 wells analyzed, only 35 contain water-level fluctuations associated with “Earth + Ocean” (7) or “Ocean” (28) tides. Permeability reduction manifest as changes in tidal behavior and increased water-levels in the near field of the Canterbury earthquake sequence of 2010–2011 support the hypothesis of shear-induced consolidation. However, tidal behavior and water-level changes rarely occurred simultaneously (~2%). Water-level changes that occurred with no change in tidal behavior reequilibrated at a new postseismic level more quickly (on timescales of ~50 min) than when a change in tidal behavior occurred (~240 min to 10 days). Water-level changes were more than likely to occur above a peak dynamic stress of ~50 kPa and were more than likely to not occur below ~10 kPa. The minimum peak dynamic stress required for a tidal behavior change to occur was ~0.2 to 100 kPa.
Post-earthquake cordons have been used after seismic events around the world. However, there is limited understanding of cordons and how contextual information of place such as geography, socio-cultural characteristics, economy, institutional and governance structure etc. affect decisions, operational procedures as well as spatial and temporal attributes of cordon establishment. This research aims to fill that gap through a qualitative comparative case study of two cities: Christchurch, New Zealand (Mw 6.2 earthquake, February 2011) and L’Aquila, Italy (Mw 6.3 earthquake, 2009). Both cities suffered comprehensive damage to its city centre and had cordons established for extended period. Data collection was done through purposive and snowball sampling methods whereby 23 key informants were interviewed in total. The interviewee varied in their roles and responsibilities i.e. council members, emergency managers, politicians, business/insurance representatives etc. We found that cordons were established to ensure safety of people and to maintain security of place in both the sites. In both cities, the extended cordon was met with resistance and protests. The extent and duration of establishment of cordon was affected by recovery approach taken in the two cities i.e. in Christchurch demolition was widely done to support recovery allowing for faster removal of cordons where as in L’Aquila, due to its historical importance, the approach to recovery was based on saving all the buildings which extended the duration of cordon. Thus, cordons are affected by site specific needs. It should be removed as soon as practicable which could be made easier with preplanning of cordons.
Background: We are in a period of history where natural disasters are increasing in both frequency and severity. They are having widespread impacts on communities, especially on vulnerable communities, those most affected who have the least ability to prepare or respond to a disaster. The ability to assemble and effectively manage Interagency Emergency Response Teams (IERTs) is critical to navigating the complexity and chaos found immediately following disasters. These teams play a crucial role in the multi-sectoral, multi-agency, multi-disciplinary, and inter-organisational response and are vital to ensuring the safety and well-being of vulnerable populations such as the young, aged, and socially and medically disadvantaged in disasters. Communication is key to the smooth operation of these teams. Most studies of the communication in IERTs during a disaster have been focussed at a macro-level of examining larger scale patterns and trends within organisations. Rarely found are micro-level analyses of interpersonal communication at the critical interfaces between collaborating agencies. This study set out to understand the experiences of those working at the interagency interfaces in an IERT set up by the Canterbury District Health Board to respond to the needs of the vulnerable people in the aftermath of the destructive earthquakes that hit Canterbury, New Zealand, in 2010-11. The aim of the study was to gain insights about the complexities of interpersonal communication (micro-level) involved in interagency response coordination and to generate an improved understanding into what stabilises the interagency communication interfaces between those agencies responding to a major disaster. Methods: A qualitative case study research design was employed to investigate how interagency communication interfaces were stabilised at the micro-level (“the case”) in the aftermath of the destructive earthquakes that hit Canterbury in 2010-11 (“the context”). Participant recruitment was undertaken by mapping which agencies were involved within the IERT and approaching representatives from each of these agencies. Data was collected via individual interviews using a semi-structured interview guide and was based on the “Critical Incident Technique”. Subsequently, data was transcribed verbatim and subjected to inductive analysis. This was underpinned theoretically by Weick’s “Interpretive Approach” and supported by Nvivo qualitative data analysis software. Results: 19 participants were interviewed in this study. Out of the inductive analysis emerged two primary themes, each with several sub-factors. The first major theme was destabilising/disruptive factors of interagency communication with five sub-factors, a) conflicting role mandates, b) rigid command structures, c) disruption of established communication structures, d) lack of shared language and understanding, and e) situational awareness disruption. The second major theme stabilising/steadying factors in interagency communication had four sub-factors, a) the establishment of the IERT, b) emergent novel communication strategies, c) establishment of a liaison role and d) pre-existing networks and relationships. Finally, there was a third sub-level identified during inductive analysis, where sub-factors from both primary themes were noted to be uniquely interconnected by emergent “consequences” arising out of the disaster context. Finally, findings were synthesised into a conceptual “Model of Interagency Communication at the Micro-level” based on this case study of the Canterbury earthquake disaster response. Discussion: The three key dimensions of The People, The Connections and The Improvisations served as a framework for the discussion of what stabilises interagency communication interfaces in a major disaster. The People were key to stabilising the interagency interfaces through functioning as a flexible conduit, guiding and navigating communication at the interagency interfaces and improving situational awareness. The Connections provided the collective competence, shared decision-making and prior established relationships that stabilised the micro-level communication at interagency interfaces. And finally, The Improvisations i.e., novel ideas and inventiveness that emerge out of rapidly changing post-disaster environments, also contributed to stabilisation of micro-level communication flows across interagency interfaces in the disaster response. “Command and control” hierarchical structures do provide clear processes and structures for teams working in disasters to follow. However, improvisations and novel solutions are also needed and often emerge from first responders (who are best placed to assess the evolving needs in a disaster where there is a high degree of uncertainty). Conclusion: This study highlights the value of incorporating an interface perspective into any study that seeks to understand the processes of IERTs during disaster responses. It also strengthens the requirement for disaster management frameworks to formally plan for and to allow for the adaptive responsiveness of local teams on the ground, and legitimise and recognise the improvisations of those in the role of emergent boundary spanners in a disaster response. This needs to be in addition to existing formal disaster response mechanisms. This study provides a new conceptual model that can be used to guide future case studies exploring stability at the interfaces of other IERTs and highlights the centrality of communication in the experiences of members of teams in the aftermath of a disaster. Utilising these new perspectives on stabilising communication at the interagency interfaces in disaster responses will have practical implications in the future to better serve the needs of vulnerable people who are at greatest risk of adverse outcomes in a disaster.
It is well known that buildings constructed using unreinforced masonry (URM) are susceptible to damage from earthquake induced lateral forces that may result in partial or full building collapse. The 2010/2011 Canterbury earthquakes are the most recent New Zealand example of destructive earthquakes, which have drawn people's attention to the inherent seismic weaknesses of URM buildings and anchored masonry veneer systems in New Zealand. A brief review of the data collected following the 2010 Darfield earthquake and more comprehensive documentation of data that was collected following the 2011 Christchurch earthquake is presented, along with the findings from subsequent data interrogation. Large stocks of earthquake prone vintage URM buildings that remain in New Zealand and in other seismically active parts of the world result in the need for minimally invasive and cost effective seismic retrofit techniques. The principal objective of the doctoral research reported herein was to investigate the applicability of near surface mounted (NSM) carbon fibre reinforced polymer (CFRP) strips as a seismic improvement technique. A comprehensive experimental program consisting of 53 pull tests is presented and is used to assess the accuracy of existing FRP-to-masonry bond models, with a modified model being proposed. The strength characteristics of vintage clay brick URM wall panels from two existing URM buildings was established and used as a benchmark when manufacturing replica clay brick test assemblages. The applicability of using NSM CFRP strips as a retrofitting technique for improving the shear strength and the ductility capacity of multi-leaf URM walls constructed using solid clay brick masonry is investigated by varying CFRP reinforcement ratios. Lastly, an experimental program was undertaken to validate the proposed design methodology for improving the strength capacity of URM walls. The program involved testing full-scale walls in a laboratory setting and testing full-scale walls in-situ in existing vintage URM buildings. Experimental test results illustrated that the NSM CFRP technique is an effective method to seismically strengthen URM buildings.
Pumice materials, which are problematic from an engineering viewpoint, are widespread in the central part of the North Island. Considering the impacts of the 2010-2011 Christchurch earthquakes, a clear understanding of their properties under earthquake loading is necessary. For example, the 1987 Edgecumbe earthquake showed evidence of localised liquefaction of sands of volcanic origin. To elucidate on this, research was undertaken to investigate whether existing empirical field-based methods to evaluate the liquefaction potential of sands, which were originally developed for hard-grained soils, are applicable to crushable pumice-rich deposits. For this purpose, two sites, one in Whakatane and another in Edgecumbe, were selected where the occurrence of liquefaction was reported following the Edgecumbe earthquake. Manifestations of soil liquefaction, such as sand boils and ejected materials, have been reported at both sites. Field tests, including cone penetration tests (CPT), shear-wave velocity profiling, and screw driving sounding (SDS) tests were performed at the sites. Then, considering estimated peak ground accelerations (PGAs) at the sites based on recorded motions and possible range of ground water table locations, liquefaction analysis was conducted at the sites using available empirical approaches. To clarify the results of the analysis, undisturbed soil samples were obtained at both sites to investigate the laboratory-derived cyclic resistance ratios and to compare with the field-estimated values. Research results clearly showed that these pumice-rich soils do not fit existing liquefaction assessment frameworks and alternate methods are necessary to characterise them.
