The previously unknown Greendale Fault was buried beneath the Canterbury Plains and ruptured in the September 4th 2010 moment magnitude (Mw) 7.1 Darfield Earthquake. The Darfield Earthquake and subsequent Mw 6 or greater events that caused damage to Christchurch highlight the importance of unmapped faults near urban areas. This thesis examines the morphology, age and origin of the Canterbury Plains together with the paleoseismology and surface-rupture displacement distributions of the Greendale Fault. It offers new insights into the surface-rupture characteristics, paleoseismology and recurrence interval of the Greendale Fault and related structures involved in the 2010 Darfield Earthquake. To help constrain the timing of the penultimate event on the Greendale Fault the origin and age of the faulted glacial outwash deposits have been examined using sedimentological analysis of gravels and optically stimulated luminescence (OSL) dating combined with analysis of GPS and LiDAR survey data. OSL ages from this and other studies, and the analysis of surface paleochannel morphology and subsurface gravel deposits indicate distinct episodes of glacial outwash activity across the Canterbury Plains, at ~20 to 24 and ~28 to 33 kyr separated by a hiatus in sedimentation possibly indicating an interstadial period. These data suggest multiple glacial periods between ~18 and 35 kyr which may have occurred throughout the Canterbury region and wider New Zealand. A new model for the Waimakariri Fan is proposed where aggradation is mainly achieved during episodic sheet flooding with the primary river channel location remaining approximately fixed. The timing, recurrence interval and displacements of the penultimate surface-rupturing earthquake on the Greendale Fault have been constrained by trenching the scarp produced in 2010 at two locations. These excavations reveal a doubling of the magnitude of surface displacement at depths of 2-4 m. Aided by OSL ages of sand lenses in the gravel deposits, this factor-of-two increase is interpreted to indicate that in the central section of the Greendale Fault the penultimate surface-rupturing event occurred between ca. 20 and 30 kyr ago. The Greendale Fault remained undetected prior to the Darfield earthquake because the penultimate fault scarp was eroded and buried during Late Pleistocene alluvial activity. The Darfield earthquake rupture terminated against the Hororata Anticline Fault (HAF) in the west and resulted in up to 400 mm of uplift on the Hororata Anticline immediately above the HAF. Folding in 2010 is compared to Quaternary and younger deformation across the anticline recorded by a seismic reflection line, GPS-measured topographic profiles along fluvial surfaces, and river channel sinuosity and morphology. It is concluded that the HAF can rupture during earthquakes dissimilar to the 2010 event that may not be triggered by slip on the Greendale Fault. Like the Greendale Fault geomorphic analyses provide no evidence for rupture of the HAF in the last 18 kyr, with the average recurrence interval for the late Quaternary inferred to be at least ~10 kyr. Surface rupture of the Greendale Fault during the Darfield Earthquake produced one of the most accessible and best documented active fault displacement and geometry datasets in the world. Surface rupture fracture patterns and displacements along the fault were measured with high precision using real time kinematic (RTK) GPS, tape and compass, airborne light detection and ranging (LiDAR), and aerial photos. This allowed for detailed analysis of the cumulative strike-slip displacement across the fault zone, displacement gradient (ground shear strain) and the type of displacement (i.e. faulting or folding). These strain profiles confirm that the rupture zone is generally wide (~30 to ~300 metres) with >50% of displacement (often 70-80%) accommodated by ground flexure rather than discrete fault slip and ground cracking. The greatest fault-zone widths and highest proportions of folding are observed at fault stepovers.
A dramatic consequence of the Christchurch, New Zealand, earthquakes of 2010 and 2011 was the widespread liquefaction in the city. Part of the central business district (CBD) was badly affected by liquefaction but elsewhere large volumes of ejecta were not evident for those parts of the CBD where the upper layers in the soil profile are sandy gravel and gravelly sand. The purpose of the paper is to investigate the effect of the gravel permeability on the rise and dissipation of excess pore water pressure during cyclic loading of a soil profile idealised from Christchurch data. The Cyclic1D software, which performs one-dimensional non-linear effective stress site response analysis, was used. Permeability values associated with gravel were found to suppress the cyclic accumulation of excess pore water pressure in gravel layers. Given that there has not been any systematic measurement of the in situ permeability of the gravels in Christchurch, the modelling in the paper suggests that likely values for the bulk permeability of the gravel layers are within the range suggested in the geotechnical literature. However, the work reported is of wider application than Christchurch and emphasises the controlling influence of permeability on the accumulation and dissipation of cyclic pore pressures. VoR - Version of Record
A number of field testing techniques, such as standard penetration test (SPT), cone penetration test (CPT), and Swedish weight sounding (SWS), are popularly used for in-situ characterisation. The screw driving sounding (SDS) method, which has been recently developed in Japan, is an improved version of the SWS technique and measures more parameters, including the required torque, load, speed of penetration and rod friction; these provide more robust way of characterising soil stratigraphy. It is a cost-efficient technique which uses a machine-driven and portable device, making it ideal for testing in small-scale and confined areas. Moreover, with a testing depth of up to 10-15m, it is suitable for liquefaction assessment. Thus, the SDS method has great potential as an in-situ testing method for geotechnical site characterisation, especially for residential house construction. In this paper, the results of SDS tests performed at a variety of sites in New Zealand are presented. The soil database was employed to develop a soil classification chart based on SDS-derived parameters. Moreover, using the data obtained following the 2010-2011 Christchurch Earthquake Se-quence, a methodology was established for liquefaction potential evaluation using SDS data. http://www.isc5.com.au/wp-content/uploads/2016/09/1345-2-ORENSE.pdf
Recycling is often employed as part of a disaster waste management system. However, the feasibility, method and effectiveness of recycling varies between disaster events. This qualitative study is based on literature reviews, expert interviews and active participatory research of five international disaster events in developed countries (2009 Victorian Bushfires, Australia; 2009 L’Aquila earthquake, Italy; 2005 Hurricane Katrina, United States; 2010 and 2011 Canterbury earthquakes, New Zealand; 2011 Great East Japan earthquake) to answer three questions: What are the main factors that affect the feasibility of recycling post-disaster? When is on-site or off-site separation more effective? What management approaches improve recycling effectiveness? Seven disaster-specific factors need to be assessed to determine the feasibility of disaster waste recycling programmes: volume of waste; degree of mixing of waste; human and environmental health hazards; areal extent of the waste; community priorities; funding mechanisms; and existing and disaster-specific regulations. The appropriateness of on or off-site waste separation depends on four factors: time constraints; resource availability; degree of mixing of waste and human and public health hazards. Successful recycling programmes require good management including clear and well enforced policies (through good contracts or regulations) and pre-event planning. Further research into post-disaster recycling markets, funding mechanisms and recycling in developing countries is recommended.
The Screw Driving Sounding (SDS) method developed in Japan is a relatively new insitu testing technique to characterise soft shallow sites, typically those required for residential house construction. An SDS machine drills a rod into the ground in several loading steps while the rod is continuously rotated. Several parameters, such as torque, load and speed of penetration, are recorded at every rotation of the rod. The SDS method has been introduced in New Zealand, and the results of its application for characterising local sites are discussed in this study. A total of 164 SDS tests were conducted in Christchurch, Wellington and Auckland to validate/adjust the methodologies originally developed based on the Japanese practice. Most of the tests were conducted at sites where cone penetration tests (CPT), standard penetration tests (SPT) and borehole logs were available; the comparison of SDS results with existing information showed that the SDS method has great potential as an in-situ testing method for classifying the soils. By compiling the SDS data from 3 different cities and comparing them with the borehole logs, a soil classification chart was generated for identifying the soil type based on SDS parameters. Also, a correlation between fines content and SDS parameters was developed and a procedure for estimating angle of internal friction of sand using SDS parameters was investigated. Furthermore, a correlation was made between the tip resistance of the CPT and the SDS data for different percentages of fines content. The relationship between the SPT N value and a SDS parameter was also proposed. This thesis also presents a methodology for identifying the liquefiable layers of soil using SDS data. SDS tests were performed in both liquefied and non-liquefied areas in Christchurch to find a representative parameter and relationship for predicting the liquefaction potential of soil. Plots were drawn of the cyclic shear stress ratios (CSR) induced by the earthquakes and the corresponding energy of penetration during SDS tests. By identifying liquefied or unliquefied layers using three different popular CPT-based methods, boundary lines corresponding to the various probabilities of liquefaction happening were developed for different ranges of fines contents using logistic regression analysis, these could then be used for estimating the liquefaction potential of soil directly from the SDS data. Finally, the drilling process involved in screw driving sounding was simulated using Abaqus software. Analysis results proved that the model successfully captured the drilling process of the SDS machine in sand. In addition, a chart to predict peak friction angles of sandy sites based on measured SDS parameters for various vertical effective stresses was formulated. As a simple, fast and economical test, the SDS method can be a reliable alternative insitu test for soil and site characterisation, especially for residential house construction.
Predictive modelling provides an efficient means to analyse the coastal environment and generate knowledge for long term urban planning. In this study, the numerical models SWAN and XBeach were incorporated into the ESRI ArcGIS interface by means of the BeachMMtool. This was applied to the Greater Christchurch coastal environment to simulate geomorphological evolution through hydrodynamic forcing. Simulations were performed using the recent sea level rise predictions by the Intergovernmental Panel on Climate Change (2013) to determine whether the statutory requirements outlined in the New Zealand Coastal Policy Statement 2010 are consistent with central, regional and district designations. Our results indicate that current land use zoning in Greater Christchurch is not consistent with these predictions. This is because coastal hazard risk has not been thoroughly quantified during the process of installing the Canterbury Earthquake Recovery Authority residential red zone. However, the Christchurch City Council’s flood management area does provide an extent to which managed coastal retreat is a real option. The results of this research suggest that progradation will continue to occur along the Christchurch foreshore due to the net sediment flux retaining an onshore direction and the current hydrodynamic activity not being strong enough to move sediment offshore. However, inundation during periods of storm surge poses a risk to human habitation on low lying areas around the Avon-Heathcote Estuary and the Brooklands lagoon.
We present ground motion simulations of the Porters Pass (PP) fault in the Canterbury region of New Zealand; a major active source near Christchurch city. The active segment of the PP fault has an inferred length of 82 km and a mostly strike-slip sense of movement. The PP fault slip makes up approximately 10% of the total 37 mm/yr margin-parallel plate motion and also comprises a significant proportion of the total strain budget in regional tectonics. Given that the closest segment of the fault is less than 45 km from Christchurch city, the PP fault is crucial for accurate earthquake hazard assessment for this major population centre. We have employed the hybrid simulation methodology of Graves and Pitarka (2010, 2015), which combines low (f<1 Hz) and high (f>1 Hz) frequencies into a broadband spectrum. We have used validations from three moderate magnitude events (𝑀𝑤4.6 Sept 04, 2010; 𝑀𝑤4.6 Nov 06, 2010; 𝑀𝑤4.9 Apr 29, 2011) to build confidence for the 𝑀𝑤 > 7 PP simulations. Thus far, our simulations include multiple rupture scenarios which test the impacts of hypocentre location and the finite-fault stochastic rupture representation of the source itself. In particular, we have identified the need to use location-specific 1D 𝑉𝑠/𝑉𝑝 models for the high frequency part of the simulations to better match observations.
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The Canterbury region of New Zealand was shaken by major earthquakes on the 4th September 2010 and 22nd February 2011. The quakes caused 185 fatalities and extensive land, infrastructure and building damage, particularly in the Eastern suburbs of Christchurch city. Almost 450 ha of residential and public land was designated as a ‘Red Zone’ unsuitable for residential redevelopment because land damage was so significant, engineering solutions were uncertain, and repairs would be protracted. Subsequent demolition of all housing and infrastructure in the area has left a blank canvas of land stretching along the Avon River corridor from the CBD to the sea. Initially the Government’s official – but enormously controversial – position was that this land would be cleared and lie fallow until engineering solutions could be found that enabled residential redevelopment. This paper presents an application of a choice experiment (CE) that identified and assessed Christchurch residents’ preferences for different land use options of this Red Zone. Results demonstrated strong public support for the development of a recreational reserve comprising a unique natural environment with native fauna and flora, healthy wetlands and rivers, and recreational opportunities that align with this vision. By highlighting the value of a range of alternatives, the CE provided a platform for public participation and expanded the conversational terrain upon which redevelopment policy took place. We conclude the method has value for land use decision-making beyond the disaster recovery context.
Despite their good performance in terms of their design objectives, many modern code-prescriptive buildings built in Christchurch, New Zealand had to be razed after the 2010-2011 Canterbury earthquakes because repairs were deemed too costly due to widespread sacrificial damage. Clearly a more effective design paradigm is needed to create more resilient structures. Rocking, post-tensioned connections with supplemental energy dissipation can contribute to a damage avoidance designs (DAD). However, few have achieved all three key design objectives of damage-resistant rocking, inherent recentering ability, and repeatable, damage-free energy dissipation for all cycles, which together offer a response which is independent of loading history. Results of experimental tests are presented for a near full-scale rocking beam-column sub-assemblage. A matrix of test results is presented for the system under varying levels of posttensioning, with and without supplemental dampers. Importantly, this parametric study delineates each contribution to response. Practical limitations on posttensioning are identified: a minimum to ensure static structural re-centering, and a maximum to ensure deformability without threadbar yielding. Good agreement between a mechanistic model and experimental results over all parameters and inputs indicates the model is robust and accurate for design. The overall results indicate that it is possible to create a DAD connection where the non-linear force-deformation response is loading history independent and repeatable over numerous loading cycles, without damage, creating the opportunity for the design and implementation of highly resilient structures.
Unreinforced masonry (URM) cavity-wall construction is a form of masonry where two leaves of clay brick masonry are separated by a continuous air cavity and are interconnected using some form of tie system. A brief historical introduction is followed by details of a survey undertaken to determine the prevalence of URM cavity-wall buildings in New Zealand. Following the 2010/2011 Canterbury earthquakes it was observed that URM cavity-walls generally suffered irreparable damage due to a lack of effective wall restraint and deficient cavity-tie connections, combined with weak mortar strength. It was found that the original cavity-ties were typically corroded due to moisture ingress, resulting in decreased lateral loadbearing capacity of the cavity-walls. Using photographic data pertaining to Christchurch URM buildings that were obtained during post-earthquake reconnaissance, 252 cavity-walls were identified and utilised to study typical construction details and seismic performance. The majority (72%, 182) of the observed damage to URM cavity-wall construction was a result of out-of-plane type wall failures. Three types of out-of-plane wall failure were recognised: (1) overturning response, (2) one-way bending, and (3) two-way bending. In-plane damage was less widely observed (28%) and commonly included diagonal shear cracking through mortar bed joints or bricks. The collected data was used to develop an overview of the most commonly-encountered construction details and to identify typical deficiencies in earthquake response that can be addressed via the selection and implementation of appropriate mitigation interventions. http://www.journals.elsevier.com/structures
The combination of music and disaster has been the subject of much study, especially starstudded telethons and songs that commemorate tragedy. However, there are many other ways that music can be used after disaster that provide benefits far greater than money or memorials but are not necessarily as prominent in the worldwide media landscape. Beginning in September 2010, the city of Christchurch, New Zealand, has been struck by several major earthquakes and over 11,000 aftershocks, the most destructive of which caused 185 deaths. As with many other disasters, music has been used as a method of fundraising and commemoration, but personal experience suggests many other ways that music can be used as a coping mechanism and aid to personal and community recovery. Therefore, in order to uncover the connections, context, and strategies behind its use, this thesis addresses the question: Since the earthquakes began, how has popular music been beneficial for the city and people of Christchurch? As well as documenting a wide variety of musical ‘earthquake relief’ events and charitable releases, this research also explores some of the more intangible aspects of the music-aid relationship. Two central themes are presented – fundraising and psychosocial uses – utilising individual voices and case studies to illustrate the benefits of music use after disaster at a community or city-wide level. Together the disparate threads and story fragments weave a detailed picture of the ways in which music as shared experience, as text, as commodity, and as a tool for memory and movement has been incorporated into the fabric of the city during the recovery phase.
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 facade 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 sleeves. In addition, the comparative performance of bent anchors (installed at an angle of minimum 22.5° 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 summary of the performed experimental program and test results, and a proposed pull-out capacity relationship for adhesive anchors installed into multi-leaf clay brick masonry are presented herein. AM - Accepted Manuscript
Eccentrically Braced Frames (EBFs) are a widely used seismic resisting structural steel system. Since their inception in the late 1970s, they have been a viable option with an available stiffness that is between simple braced systems and moment resisting systems. A similar concept, the linked column frame (LCF), uses shear links between two closely spaced columns. In both cases, the key component is the active link or the shear link, and this component is the objective of this study. The performance of high rise EBF buildings in the 2010 and 2011 Christchurch earthquakes was beyond that which was expected, especially considering the very high accelerations recorded. As the concrete high-rises were torn down, two EBF buildings remained standing and only required some structural repair. These events prompted a renewed interest in bolted shear links, as well as their performance. While some research into replaceable shear links had already been done (Mansour, 2011), the objectives of this study were to improve on the shear link itself, with the consideration that links built in the future are likely to be bolted. The main components of this study were to: 1. Reduce or eliminate the requirements for intermediate web stiffeners, as they were suspected of being detrimental to performance. Furthermore, any reduction in stiffening requirements is a direct fabrication cost saving. Links with low web aspect ratios were found to achieve exceptional ductilities when no stiffeners were included, prompting new design equations. 2. Ensure that the stresses in the ends of links are adequately transferred into the endplates without causing fractures. Although most of the experimental links had web doubler plates included, four had varied lengths of such doubler plates from 0.0 in. to 8.0 in. The link without any doubler plates performed to a similar level to its peers, and thus it is likely that links with quality end details may not need web doubler plates at all. 3. Evaluate the performance of a link with double sided stiffeners without the use of web welds, as opposed to conventional single sided, welded stiffeners. This link performed well, and web-weld-less double sided stiffeners may be an economical alternative to conventional stiffeners for deeper sections of links. 4. Evaluate the performance of a link with thin endplates that are made efficient with the use of gusset plates. This link performed to an acceptable level and provides evidence for a cost effective alternative to thick endplates, especially considering the high overstrength end moments in links, typically requiring 16-bolt connections. 5. Examine the potential use of an alternative EBF arrangement where the collector beam is over sized, and the link section is formed by cutting out parts of the beam's web. After running a series of finite element models each with a unique variation, a number of approximate design rules were derived such that future research could develop this idea further experimentally. 6. Ensure that during testing, the secondary elements (members that are not the shear link), do not yield and are not close to yielding. None of the instrumented elements experienced any unexpected yielding, however the concerns for high stresses in the collector beam panel zone during design were warranted. The use of an existing New Zealand design equation is recommended as an extra check for design codes worldwide. The above objectives were mainly conducted experimentally, except: the data set for item 1 was greatly expanded through the use of a calibrated numerical model which was then used in an extensive parametric study; item 5 was purely finite element based; and, a small parametric study was included for item 3 in an attempt to expand on the trends found there.
Sewerage systems convey sewage, or wastewater, from residential or commercial buildings through complex reticulation networks to treatment plants. During seismic events both transient ground motion and permanent ground deformation can induce physical damage to sewerage system components, limiting or impeding the operability of the whole system. The malfunction of municipal sewerage systems can result in the pollution of nearby waterways through discharge of untreated sewage, pose a public health threat by preventing the use of appropriate sanitation facilities, and cause serious inconvenience for rescuers and residents. Christchurch, the second largest city in New Zealand, was seriously affected by the Canterbury Earthquake Sequence (CES) in 2010-2011. The CES imposed widespread damage to the Christchurch sewerage system (CSS), causing a significant loss of functionality and serviceability to the system. The Christchurch City Council (CCC) relied heavily on temporary sewerage services for several months following the CES. The temporary services were supported by use of chemical and portable toilets to supplement the damaged wastewater system. The rebuild delivery agency -Stronger Christchurch Infrastructure Rebuild Team (SCIRT) was created to be responsible for repair of 85 % of the damaged horizontal infrastructure (i.e., water, wastewater, stormwater systems, and roads) in Christchurch. Numerous initiatives to create platforms/tools aiming to, on the one hand, support the understanding, management and mitigation of seismic risk for infrastructure prior to disasters, and on the other hand, to support the decision-making for post-disaster reconstruction and recovery, have been promoted worldwide. Despite this, the CES in New Zealand highlighted that none of the existing platforms/tools are either accessible and/or readable or usable by emergency managers and decision makers for restoring the CSS. Furthermore, the majority of existing tools have a sole focus on the engineering perspective, while the holistic process of formulating recovery decisions is based on system-wide approach, where a variety of factors in addition to technical considerations are involved. Lastly, there is a paucity of studies focused on the tools and frameworks for supporting decision-making specifically on sewerage system restoration after earthquakes. This thesis develops a decision support framework for sewerage pipe and system restoration after earthquakes, building on the experience and learning of the organisations involved in recovering the CSS following the CES in 2010-2011. The proposed decision support framework includes three modules: 1) Physical Damage Module (PDM); 2) Functional Impact Module (FIM); 3) Pipeline Restoration Module (PRM). The PDM provides seismic fragility matrices and functions for sewer gravity and pressure pipelines for predicting earthquake-induced physical damage, categorised by pipe materials and liquefaction zones. The FIM demonstrates a set of performance indicators that are categorised in five domains: structural, hydraulic, environmental, social and economic domains. These performance indicators are used to assess loss of wastewater system service and the induced functional impacts in three different phases: emergency response, short-term recovery and long-term restoration. Based on the knowledge of the physical and functional status-quo of the sewerage systems post-earthquake captured through the PDM and FIM, the PRM estimates restoration time of sewer networks by use of restoration models developed using a Random Forest technique and graphically represented in terms of restoration curves. The development of a decision support framework for sewer recovery after earthquakes enables decision makers to assess physical damage, evaluate functional impacts relating to hydraulic, environmental, structural, economic and social contexts, and to predict restoration time of sewerage systems. Furthermore, the decision support framework can be potentially employed to underpin system maintenance and upgrade by guiding system rehabilitation and to monitor system behaviours during business-as-usual time. In conjunction with expert judgement and best practices, this framework can be moreover applied to assist asset managers in targeting the inclusion of system resilience as part of asset maintenance programmes.
A video of the keynote presentation by Alexander C. McFarlane during the third plenary of the 2016 People in Disasters Conference. McFarlane is a Professor of Psychiatry at the University of Adelaide and the Heady of the Centre for Traumatic Stress Studies. The presentation is titled, "Holding onto the Lessons Disasters Teach".The abstract for this presentation reads as follows: Disasters are sentinel points in the life of the communities affected. They bring an unusual focus to community mental health. In so doing, they provide unique opportunities for better understanding and caring for communities. However, one of the difficulties in the disaster field is that many of the lessons from previous disasters are frequently lost. If anything, Norris (in 2006) identified that the quality of disaster research had declined over the previous 25 years. What is critical is that a longitudinal perspective is taken of representative cohorts. Equally, the impact of a disaster should always be judged against the background mental health of the communities affected, including emergency service personnel. Understandably, many of those who are particularly distressed in the aftermath of a disaster are people who have previously experienced a psychiatric disorder. It is important that disaster services are framed against knowledge of this background morbidity and have a broad range of expertise to deal with the emerging symptoms. Equally, it is critical that a long-term perspective is considered rather than short-term support that attempts to ameliorate distress. Future improvement of disaster management depends upon sustaining a body of expertise dealing with the consequences of other forms of traumatic stress such as accidents. This expertise can be redirected to co-ordinate and manage the impact of larger scale events when disasters strike communities. This presentation will highlight the relevance of these issues to the disaster planning in a country such as New Zealand that is prone to earthquakes.
Natural hazard disasters often have large area-wide impacts, which can cause adverse stress-related mental health outcomes in exposed populations. As a result, increased treatment-seeking may be observed, which puts a strain on the limited public health care resources particularly in the aftermath of a disaster. It is therefore important for public health care planners to know whom to target, but also where and when to initiate intervention programs that promote emotional wellbeing and prevent the development of mental disorders after catastrophic events. A large body of literature assesses factors that predict and mitigate disaster-related mental disorders at various time periods, but the spatial component has rarely been investigated in disaster mental health research. This thesis uses spatial and spatio-temporal analysis techniques to examine when and where higher and lower than expected mood and anxiety symptom treatments occurred in the severely affected Christchurch urban area (New Zealand) after the 2010/11 Canterbury earthquakes. High-risk groups are identified and a possible relationship between exposure to the earthquakes and their physical impacts and mood and anxiety symptom treatments is assessed. The main research aim is to test the hypothesis that more severely affected Christchurch residents were more likely to show mood and anxiety symptoms when seeking treatment than less affected ones, in essence, testing for a dose-response relationship. The data consisted of mood and anxiety symptom treatment information from the New Zealand Ministry of Health’s administrative databases and demographic information from the National Health Index (NHI) register, when combined built a unique and rich source for identifying publically funded stress-related treatments for mood and anxiety symptoms in almost the whole population of the study area. The Christchurch urban area within the Christchurch City Council (CCC) boundary was the area of interest in which spatial variations in these treatments were assessed. Spatial and spatio-temporal analyses were done by applying retrospective space-time and spatial variation in temporal trends analysis using SaTScan™ software, and Bayesian hierarchical modelling techniques for disease mapping using WinBUGS software. The thesis identified an overall earthquake-exposure effect on mood and anxiety symptom treatments among Christchurch residents in the context of the earthquakes as they experienced stronger increases in the risk of being treated especially shortly after the catastrophic 2011 Christchurch earthquake compared to the rest of New Zealand. High-risk groups included females, elderly, children and those with a pre-existing mental illness with elderly and children especially at-risk in the context of the earthquakes. Looking at the spatio-temporal distribution of mood and anxiety symptom treatments in the Christchurch urban area, a high rates cluster ranging from the severely affected central city to the southeast was found post-disaster. Analysing residential exposure to various earthquake impacts found that living in closer proximity to more affected areas was identified as a risk factor for mood and anxiety symptom treatments, which largely confirms a dose-response relationship between level of affectedness and mood and anxiety symptom treatments. However, little changes in the spatial distribution of mood and anxiety symptom treatments occurred in the Christchurch urban area over time indicating that these results may have been biased by pre-existing spatial disparities. Additionally, the post-disaster mobility activity from severely affected eastern to the generally less affected western and northern parts of the city seemed to have played an important role as the strongest increases in treatment rates occurred in less affected northern areas of the city, whereas the severely affected eastern areas tended to show the lowest increases. An investigation into the different effects of mobility confirmed that within-city movers and temporary relocatees were generally more likely to receive care or treatment for mood or anxiety symptoms, but moving within the city was identified as a protective factor over time. In contrast, moving out of the city from minor, moderately or severely damaged plain areas of the city, which are generally less affluent than Port Hills areas, was identified as a risk factor in the second year post-disaster. Moreover, residents from less damaged plain areas of the city showed a decrease in the likelihood of receiving care or treatment for mood or anxiety symptoms compared to those from undamaged plain areas over time, which also contradicts a possible dose-response relationship. Finally, the effects of the social and physical environment, as well as community resilience on mood and anxiety symptom treatments among long-term stayers from Christchurch communities indicate an exacerbation of pre-existing mood and anxiety symptom treatment disparities in the city, whereas exposure to ‘felt’ earthquake intensities did not show a statistically significant effect. The findings of this thesis highlight the complex relationship between different levels of exposure to a severe natural disaster and adverse mental health outcomes in a severely affected region. It is one of the few studies that have access to area-wide health and impact information, are able to do a pre-disaster / post-disaster comparison and track their sample population to apply spatial and spatio-temporal analysis techniques for exposure assessment. Thus, this thesis enhances knowledge about the spatio-temporal distribution of adverse mental health outcomes in the context of a severe natural disaster and informs public health care planners, not only about high-risk groups, but also where and when to target health interventions. The results indicate that such programs should broadly target residents living in more affected areas as they are likely to face daily hardship by living in a disrupted environment and may have already been the most vulnerable ones before the disaster. Special attention should be focussed on women, elderly, children and people with pre-existing mental illnesses as they are most likely to receive care or treatment for stress-related mental health symptoms. Moreover, permanent relocatees from affected areas and temporarily relocatees shortly after the disaster may need special attention as they face additional stressors due to the relocation that may lead to the development of adverse mental health outcomes needing treatment.
A video of a presentation by Dr Lesley Campbell during the Community and Social Recovery Stream of the 2016 People in Disasters Conference. The presentation is titled, "Canterbury Family Violence Collaboration: An innovative response to family violence following the Canterbury earthquakes - successes, challenges, and achievements".The abstract for this presentation reads as follows: Across a range of international jurisdictions there is growing evidence that shows a high prevalence of family violence, child abuse and sexual violence over a number of years following natural disasters (World Health Organisation, 2005). Such empirical findings were also reflected within the Canterbury region following the earthquake events in 2010 and 2011. For example, in the weekend following the September 2010 earthquake, Canterbury police reported a 53% increase in call-outs to family violence incidents. In 2012, Canterbury police investigated over 7,400 incidents involving family violence - approximately 19 incidents each day. Child, youth and family data also reflect an increase in family violence, with substantiated cases of abuse increasing markedly from 1,130 cases in 2009 to 1,650 cases in 2011. These numbers remain elevated. Challenging events like the Canterbury earthquakes highlight the importance of, and provide the catalyst for, strengthening connections with various communities of interest to explore new ways of responding to the complex issue of family violence. It was within this context that the Canterbury Family Violence Collaboration (Collaboration) emerged. Operating since 2012, the Collaboration now comprises 45 agencies from across governmental and non-governmental sectors. The Collaboration's value proposition is that it delivers system-wide responses to family violence that could not be achieved by any one agency. These responses are delivered within five strategic priority areas: housing, crisis response and intervention, prevention, youth, and staff learning and development. The purpose of this presentation is to describe the experiences of the collaborative effort and lessons learnt by the collaborative partners in the first three years after its establishment. It will explore the key successes and challenges of the collaborative effort, and outline the major results achieved - a unique contribution, in unique circumstances, to address family violence experienced by Canterbury people throughout the period of recovery and rebuild.
The Forsyth Barr building has stood silent and empty (except the occasional intruder and pigeons) since the February 2011 earthquake. It was sold "as is" and I understand that it is now going to be fitted out as a hotel. This is the building that had severe stairwell damage during the quake necessitating people being lowered via ropes etc on t...
A section of retaining wall that tilted in the Christchurch 2011 earthquake. At the Edmunds Band Rotunda sight. Still not repaired,
Pigeons sit on the remains of one of the tallest buildings in Christchurch that was 95% demolished two or three years ago. The basement (now filled with water) and the columns remain. Demolished due to damage from the Christchurch 2011 earthquake.
This paper reports on a service-learning public journalism project in which postgraduate journalism students explore ways to engage with and report on diverse communities. Media scholars have argued that news media, and local newspapers in particular, must re-engage with their communities. Likewise, journalism studies scholars have urged educators to give journalism students greater opportunities to reflect on their work by getting out among journalism’s critics, often consumers or citizens concerned about content and the preparation of future journalists. The challenge for journalism educators is to prepare students for working in partnership with communities while also developing their ability to operate reflectively and critically within the expectations of the news media industry and wider society. The aim of this project has been to help students find ways to both listen and lead in a community, and also reflect on the challenges and critiques of community journalism practices. The project began in 2013 with stories about residents’ recovery following the devastating 2011 Canterbury earthquakes, and aimed to create stories that could contribute to community connection and engagement, and thereby resilience and recovery. The idea was inspired by research about post-disaster renewal that indicated that communities with strong social capital and social networks were more resilient and recovered more quickly and strongly. The project’s longer-term aim has been to explore community journalism practices that give greater power to citizens and communities by prioritising listening and processes of engagement. Over several months, students network with a community group to identify subjects with whom they will co-create a story, and then complete a story on which they must seek the feedback of their subject. Community leaders have described the project as a key example of how to do things “with people not to people”, and an outstanding contribution to the community-led component of Canterbury’s recovery. Analysis of student reflections, which are a key part of each year’s project, reveals the process of engaging with communities has helped students to map community dynamics, think more critically about source relationships, editorial choices and objectivity norms, and to develop a perspective on the diverse ways they can go about their journalism in the future. Each year, students partner with different groups and organisations, addressing different themes each time the project runs. For 2016, the programme proposes to develop the project in a new way, by not just exploring a community’s stories but also exploring its media needs and it aims to work with Christchurch’s new migrant Filipino community to develop the groundwork for a community media and/or communication platform, which Filipino community leaders say is a pressing need. For this iteration, journalism students will be set further research tasks aimed at deepening their ‘public listening’: they will conduct a survey of community members’ media use and needs as well as qualitative research interviews. It is hoped that the data collected will strengthen students’ understanding of their own journalism practice, as well as form the basis for work on developing media tools for minority groups who are generally poorly represented in mainstream media. In 2015, the journalism programme surveyed its community partners and held follow-up interviews with 13 of 18 story subjects to elicit further feedback on its news content and thereby deepen understanding of different community viewpoints. The survey and interview data revealed the project affected story subjects in a number of positive and interesting ways. Subjects said they appreciated the way student reporters took their time to build relationships and understand the context of the community groups with which they were involved, and contrasted this with their experience of professional journalists who had held pre-conceived assumptions about stories and/or rushed into interviews. As a direct consequence of the students’ approach, participants said they better trusted the student journalists to portray them accurately and fairly. Most were also encouraged by the positive recognition stories brought and several said the engagement process had helped their personal development, all of which had spin-offs for their community efforts. The presentation night that wraps up each year’s project, where community groups, story subjects and students come together to network and share the final stories, was cited as a significant positive aspect of the project and a great opportunity for community partners to connect with others doing similar work. Community feedback will be sought in future projects to inform and improve successive iterations.
A video of a presentation by Jane Murray and Stephen Timms during the Social Recovery Stream of the 2016 People in Disasters Conference. The presentation is titled, "Land Use Recovery Plan: How an impact assessment process engaged communities in recovery planning".The abstract for this presentation reads as follows: In response to the Canterbury earthquakes, the Minister for Canterbury Earthquake Recovery directed Environment Canterbury (Canterbury's regional council) to prepare a Land Use Recovery Plan that would provide a spatial planning framework for Greater Christchurch and aid recovery from the Canterbury earthquakes. The Land Use Recovery Plan sets a policy and planning framework necessary to rebuild existing communities and develop new communities. As part of preparing the plan, an integrated assessment was undertaken to address wellbeing and sustainability concerns. This ensured that social impacts of the plan were likely to achieve better outcomes for communities. The process enabled a wide range of community and sector stakeholders to provide input at the very early stages of drafting the document. The integrated assessment considered the treatment of major land use issues in the plan, e.g. overall distribution of activities across the city, integrated transport routes, housing typography, social housing, employment and urban design, all of which have a key impact on health and wellbeing. Representatives from the Canterbury Health in All Policies Partnership were involved in designing a three-part assessment process that would provide a framework for the Land Use Recovery Plan writers to assess and improve the plan in terms of wellbeing and sustainability concerns. The detail of these assessment stages, and the influence that they had on the draft plan, will be outlined in the presentation. In summary, the three stages involved: developing key wellbeing and sustainability concerns that could form a set of criteria, analysing the preliminary draft of the Land Use Recovery Plan against the criteria in a broad sector workshop, and analysing the content and recommendations of the Draft Plan. This demonstrates the importance of integrated assessment influencing the Land Use Recovery Plan that in turn influences other key planning documents such as the District Plan. This process enabled a very complex document with wide-ranging implications to be broken down, enabling many groups, individuals and organisations to have their say in the recovery process. There is also a range of important lessons for recovery that can be applied to other projects and actions in a disaster recovery situation.
The Canterbury earthquakes in 2010 and 2011 had a significant impact on landlords and tenants of commercial buildings in the city of Christchurch. The devastation wrought on the city was so severe that in an unprecedented response to this disaster a cordon was erected around the central business district for nearly two and half years while demolition, repairs and rebuilding took place. Despite the destruction, not all buildings were damaged. Many could have been occupied and used immediately if they had not been within the cordoned area. Others had only minor damage but repairs to them could not be commenced, let alone completed, owing to restrictions on access caused by the cordon. Tenants were faced with a major problem in that they could not access their buildings and it was likely to be a long time before they would be allowed access again. The other problem was uncertainty about the legal position as neither the standard form leases in use, nor any statute, provided for issues arising from an inaccessible building. The parties were therefore uncertain about their legal rights and obligations in this situation. Landlords and tenants were unsure whether tenants were required to pay rent for a building that could not be accessed or whether they could terminate their leases on the basis that the building was inaccessible. This thesis looks at whether the common law doctrine of frustration could apply to leases in these circumstances, where the lease had made no provision. It analyses the history of the doctrine and how it applies to a lease, the standard form leases in use at the time of the earthquakes and the unexpected and extraordinary nature of the earthquakes. It then reports on the findings of the qualitative empirical research undertaken to look at the experiences of landlords and tenants after the earthquakes. It is argued that the circumstances of landlords and tenants met the test for the doctrine of frustration. Therefore, the doctrine could have applied to leases to enable the parties to terminate them. It concludes with a suggestion for reform in the form of a new Act to govern the special relationship between commercial landlords and tenants, similar to legislation already in place covering other types of relationships like those in residential tenancies and employment. Such legislation could provide dispute resolution services to enable landlords and tenants to have access to justice to determine their legal rights at all times, and in particular, in times of crisis.
Tsunami have the potential to cause significant disruptions to society, including damage to infrastructure, critical to the every-day operation of society. Effective risk management is required to reduce the potential tsunami impacts to them. Christchurch city, situated on the eastern coast of New Zealand’s South Island, is exposed to a number of far-field tsunami hazards. Although the tsunami hazard has been well identified for Christchurch city infrastructure, the likely impacts have not been well constrained. To support effective risk management a credible and realistic infrastructure impact model is required to inform risk management planning. The objectives of this thesis are to assess the impacts on Christchurch city infrastructure from a credible, hypothetical far-field tsunami scenario. To achieve this an impact assessment process is adopted, using tsunami hazard and exposure measures to determine asset vulnerability and subsequent impacts. However, the thesis identified a number of knowledge gaps in infrastructure vulnerability to tsunami. The thesis addresses this by using two approaches: a tsunami damage matrix; and the development of tsunami fragility functions. The tsunami damage matrix pools together tsunami impacts on infrastructure literature, and post-event field observations. It represents the most comprehensive ‘look-up’ resource for tsunami impacts to infrastructure to date. This damage matrix can inform the assessment of tsunami impacts on Christchurch city infrastructure by providing a measure of damage likelihood at various hazard intensities. A more robust approach to tsunami vulnerability of infrastructure are fragility functions, which are also developed in this thesis. These were based on post-event tsunami surveys of the 2011 ‘Tohoku’ earthquake tsunami in Japan. The fragility functions are limited to road and bridge infrastructure, but represent the highest resolution measure of vulnerability for the given assets. As well as providing a measure of damage likelihood for a given tsunami hazard intensity, these also indicate a level of asset damage. The impact assessment process, and synthesized vulnerability measures, are used to run tsunami impact models for Christchurch infrastructure to determine the probability of asset damage occurring and to determine if impact will reach or exceed a given damage state. The models suggest that infrastructure damage is likely to occur in areas exposed to tsunami inundation in this scenario, with significant damage identified for low elevation roads and bridges. The results are presented and discussed in the context of the risk management framework, with emphasis on using risk assessment to inform risk treatment, monitoring and review. In summary, this thesis A) advances tsunami vulnerability and impact assessment methodologies for infrastructure and B) provides a tsunami impact assessment framework for Christchurch city infrastructure which will inform infrastructure tsunami risk management for planners, emergency managers and lifelines groups.
A video of a presentation by Garry Williams during the fourth plenary of the 2016 People in Disasters Conference. Williams is the Programme Manager of the Ministry of Education's Greater Christchurch Education Renewal Programme. The presentation is titled, "Education Renewal: A section response to the February 2011 Christchurch earthquake".The abstract for this presentation reads as follows: The Canterbury earthquakes caused a disaster recovery situation unparalleled in New Zealand's history. In addition to widespread damage to residential dwellings and destruction of Christchurch's central business district, the earthquakes damaged more than 200 schools from Hurunui in the north, to the Mackenzie District in the east, and Timaru in the south. The impact on education provision was substantial, with the majority of early childhood centres, schools and tertiary providers experiencing damage or subsequent, with the majority of early childhood centres, schools and tertiary providers experiencing damage or subsequent operational issues caused by the ensuing migration of people. Following the February earthquake, over 12,000 students had left the school they had been attending and enrolled elsewhere - often at a school outside the region. Shortened school days and compression of teaching into short periods meant shift-sharing students engaged in the curriculum being delivered in more diverse ways. School principals and staff reported increased fatigue and stress and changes in student behaviours, often related to repeated exposure to and ongoing reminders of the trauma of the earthquakes. While there has been a shift from direct, trauma-related presentations to the indirect effects of psychological adversity and daily life stresses, international experiences tells us that psychological recovery generally lags behind the immediate physical recovery and rebuilding. The Ministries of Health and Education and the Canterbury District Health Board have developed and implemented a joint action plan to address specifically the emerging mental health issues for youth in Canterbury. However, the impact of vulnerable and stressed adults on children's behaviour contributes to the overall impact of ongoing wellbeing issues on the educational outcomes for the community. There is substantial evidence supporting the need to focus on adults' resilience so they can support children and youth. Much of the Ministry's work around supporting children under stress is through supporting the adults responsible for teaching them and leading their schools. The education renewal programme exists to assist education communities to rebuild and look toward renewal. The response to the earthquakes provides a significant opportunity to better meet the needs and aspirations of children and youth people. All the parents want to see their children eager to learn, achieving success, and gaining knowledge and skills that will, in time, enable them to become confident, adaptable, economically independent adults. But this is not always the case, hence our approach to education renewal seeks to address inequities and improve outcome, while prioritising actions that will have a positive impact on learners in greatest need of assistance.
The Subway shop in the High Street Mall has not operated since lunch time on the 22nd February 2011 when the most damaging of Christchurch and Canterbury's earthquakes struck. I assume the building is still to be demolished.
Liquefaction-induced lateral spreading in large seismic events often results in pervasive and costly damage to engineering structures and lifelines, making it a critical component of engineering design. However, the complex nature of this phenomenon leads to designing for such a hazard extremely challenging and there is a clear for an improved understanding and predicting liquefaction-induced lateral spreading. The 2010-2011 Canterbury (New Zealand) Earthquakes triggered severe liquefaction-induced lateral spreading along the streams and rivers of the Christchurch region, causing extensive damage to roads, bridges, lifelines, and structures in the vicinity. The unfortunate devastation induced from lateral spreading in these events also rendered the rare opportunity to gain an improved understanding of lateral spreading displacements specific to the Christchurch region. As part of this thesis, the method of ground surveying was employed following the 4 September 2010 Darfield (Mw 7.1) and 22 February 2011 Christchurch (Mw 6.2) earthquakes at 126 locations (19 repeated) throughout Christchurch and surrounding suburbs. The method involved measurements and then summation of crack widths along a specific alignment (transect) running approximately perpendicular to the waterway to indicate typically a maximum lateral displacement at the bank and reduction of the magnitude of displacements with distance from the river. Rigorous data processing and comparisons with alternative measurements of lateral spreading were performed to verify results from field observations and validate the method of ground surveying employed, as well as highlight the complex nature of lateral spreading displacements. The welldocumented field data was scrutinized to gain an understanding of typical magnitudes and distribution patterns (distribution of displacement with distance) of lateral spreading observed in the Christchurch area. Maximum displacements ranging from less than 10 cm to over 3.5 m were encountered at the sites surveyed and the area affected by spreading ranged from less than 20 m to over 200 m from the river. Despite the highly non-uniform displacements, four characteristic distribution patterns including large, distributed ground displacements, block-type movements, large and localized ground displacements, and areas of little to no displacements were identified. Available geotechnical, seismic, and topographic data were collated at the ground surveying sites for subsequent analysis of field measurements. Two widely-used empirical models (Zhang et al. (2004), Youd et al. (2002)) were scrutinized and applied to locations in the vicinity of field measurements for comparison with model predictions. The results indicated generally poor correlation (outside a factor of two) with empirical predictions at most locations and further validated the need for an improved, analysis- based method of predicting lateral displacements that considers the many factors involved on a site-specific basis. In addition, the development of appropriate model input parameters for the Youd et al. (2002) model led to a site-specific correlation of soil behavior type index, Ic, and fines content, FC, for sites along the Avon River in Christchurch that matched up well with existing Ic – FC relationships commonly used in current practice. Lastly, a rigorous analysis was performed for 25 selected locations of ground surveying measurements along the Avon River where ground slope conditions are mild (-1 to 2%) and channel heights range from about 2 – 4.5 m. The field data was divided into categories based on the observed distribution pattern of ground displacements including: large and distributed, moderate and distributed, small to negligible, and large and localized. A systematic approach was applied to determine potential critical layers contributing to the observed displacement patterns which led to the development of characteristic profiles for each category considered. The results of these analyses outline an alternative approach to the evaluation of lateral spreading in which a detailed geotechnical analysis is used to identify the potential for large spreading displacements and likely spatial distribution patterns of spreading. Key factors affecting the observed magnitude and distribution of spreading included the thickness of the critical layer, relative density, soil type and layer continuity. It was found that the large and distributed ground displacements were associated with a thick (1.5 – 2.5 m) deposit of loose, fine to silty sand (qc1 ~4-7 MPa, Ic 1.9-2.1, qc1n_cs ~50-70) that was continuous along the bank and with distance from the river. In contrast, small to negligible displacements were characterized by an absence of or relatively thin (< 1 m), discontinuous critical layer. Characteristic features of the moderate and distributed displacements were found to be somewhere between these two extremes. The localized and large displacements showed a characteristic critical layer similar to that observed in the large and distributed sites but that was not continuous and hence leading to the localized zone of displacement. The findings presented in this thesis illustrate the highly complex nature of lateral displacements that cannot be captured in simplified models but require a robust geotechnical analysis similar to that performed for this research.
One of the less understood geotechnical responses to the cyclic loading from the MW6.2 Christchurch Earthquake, on the 22nd of February 2011, is the fissuring in the loessial soil-mantled, footslope positions of the north-facing valleys of the Port Hills. The fissures are characterized by mostly horizontal offset (≤500mm), with minor vertical displacement (≤300mm), and they extend along both sides of valleys for several hundred metres in an approximately contour-parallel orientation. The fissure traces correspond to extensional features mapped in other studies. Previous studies have suggested that the fissures are the headscarps of incipient landslides, but the surface and subsurface features are not typical of landslide movement. Whilst there are some features that correlate with landslide movement, there are many features that contradict the landslide movement hypothesis. Of critical importance to this investigation was the fact that there are no landslide flanks, there has been no basal shear surface found, there is little deformation in the so-called ‘landslide body’, and there have been no recorded zones of low shear strength in the soil deposit that are indicative of a basal shear surface. This thesis is a detailed geotechnical study on the fissures along part of Ramahana Road in the Hillsborough Valley, Christchurch. Shallow and deep investigation methods found that the predominant soil is loess-colluvium, to depths of ~20m, and this soil has variable geotechnical characteristics depending on the layer sampled. The factor that has the most influence on shear strength was found to be the moisture content. Direct shear-box testing of disturbed, recompacted loess-colluvium found that the soil had a cohesion of 35-65kPa and a friction angle of 38-43° when the soil moisture content was at 8-10%. However when the moisture content was at 19-20% the soil’s cohesion decreased to 3-5kPa and its friction angle decreased to 33-38°, this moisture content is at or slightly above the plastic limit. An electrical resistivity geophysical survey was conducted perpendicular to multiple fissure traces and through the compressional zone at 17 Ramahana Road. The electrical resistivity line found that there was an area of high resistivity at the toe of the slope, and an area of high conductivity downslope of this and at greater depths. This area correlated to the compressional zone recorded by previous studies. Moisture content testing of the soil in these locations showed that the soil in the resistive area was relatively dry (9%) compared to the surrounding soil (13%), whilst the soil in the conductive area was relatively wet (22%)compared to the surrounding soil (19%). Density tests of the soil in the compressional zone recorded that the resistive area had a higher dry density than the surrounding soil (~1790 kg/m3 compared to ~1650 kg/m3). New springs arose downslope of the compressional zone contemporaneously with the fissures, and it is interpreted that these have arisen from increased hydraulic head in the Banks Peninsula bedrock aquifer system, and earthquake induced-bedrock fracturing. A test pit was dug across an infilled fissure trace at 17 Ramahana Road to a depth of 3m. The fissure trace had an aperture of 450-470mm at the ground surface, but it gradually lost aperture with depth until 2.0-2.1m where it became a segmented fissure trace with 1-2mm aperture. A mixed-colluvium layer was intercepted by the fissure trace at 2.4m depth, and there was no observable vertical offset of this layer. The fissure trace was at an angle of 78° at the ground surface, but it also flattened with depth, which gave it a slightly curved appearance. The fissure trace was at an assumed angle of 40-50° near the base of the test pit. Rotational slide, translational slide and lateral spread landslide movement types were compared and contrasted as possibilities for landslide movement types, whilst an alternative hypothesis was offered that the fissures are tensile failures with a quasi-toppling motion involving a cohesive block of loessial soil moving outwards from the slope, with an accommodating compressional strain in the lower less cohesive soil. The mechanisms behind this movement are suggested to be the horizontal earthquake inertia forces from the Christchurch Earthquake, the static shear stress of the slope, and bedrock uplift of the Port Hills in relation to the subsidence of the Christchurch city flatlands. Extremely high PGA is considered to be a prerequisite to the fissure trace development, and these can only be induced in the Hillsborough Valley from a Port Hills Fault rupture, which has a recurrence interval of ~10,000 years. The current understanding of how the loess-colluvium soil would behave under cyclic loading is limited, and the mechanisms behind the suggested movement type are not completely understood. Further research is needed to confirm the proposed mechanism of the fissure traces. Laboratory tests such as the cyclic triaxial and cyclic shear test would be beneficial in future research to quantitatively test how the soil behaves under cyclic loading at various moisture contents and clay contents, and centrifuge experiments would be of great use to qualitatively test the suggested mode of movement in the loessial soil.