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.
The extent of liquefaction in the eastern suburbs of Christchurch (Aranui, Bexley, Avonside, Avonhead and Dallington) from the February 22 2011 Earthquake resulted in extensive damage to in-ground waste water pipe systems. This caused a huge demand for portable toilets (or port-a-loos) and companies were importing them from outside Canterbury and in some instances from Australia. However, because they were deemed “assets of importance” under legislation, their allocation had to be coordinated by Civil Defence and Emergency Management (CDEM). Consequently, companies supplying them had to ignore requests from residents, businesses and rest homes; and commitments to large events outside of the city such as the Hamilton 400 V8 Supercars and the Pasifika Festival in Auckland were impacted. Frustrations started to show as neighbourhoods questioned the equity of the port-a-loos distribution. The Prime Minister was reported as reassuring citizens in the eastern suburbs in the first week of March that1 “a report about the distribution of port-a-loos and chemical toilets shows allocation has been fair. Key said he has asked Civil Defence about the distribution process and where the toilets been sent. He said there aren’t enough for the scale of the event but that is quickly being rectified and the need for toilets is being reassessed all the time.” Nonetheless, there still remained a deep sense of frustration and exclusion over the equity of the port-a-loos distribution. This study took the simple approach of mapping where those port-a-loos were on 11-12 March for several areas in the eastern suburbs and this suggested that their distribution was not equitable and was not well done. It reviews the predictive tools available for estimating damage to waste water pipes and asks the question could this situation have been better planned so that pot-a-loo locations could have been better prioritised? And finally it reviews the integral roles of communication and monitoring as part of disaster management strategy. The impression from this study is that other New Zealand urban centres could or would also be at risk and that work is need to developed more rational management approaches for disaster planning.
In Aotearoa, New Zealand people are living longer, alongside a slowing birthrate, the older population is growing faster than the younger population. As people live longer, there is an increased need for social services and support that cater for older persons, including care takers, mental health services, and community groups. Social work plays an important role in an ageing society because it addresses the multifaceted needs for older people. While there has been recent research conducted on the experiences of older persons, none have been undertaken in the unique context of the Eastern suburbs of Ōtautahi, Christchurch, an area adversely impacted by the 2011 earthquakes. This research specifically looks at the experiences of older residents in the East, considering various intersecting characteristics such as age, gender, ethnicity, socioeconomic status, available supports, community engagement and relationships to explore the multifaceted experiences and needs of this cohort. This research is a qualitative study influenced by intersectionality and place theories. Both underpinning theories are important in understanding social dynamics, identities, and lived experiences within this community research project. I interviewed nine participants from the Eastern suburbs of Ōtautahi, Christchurch using semi-structured interviews. Interviews were analysed using thematic analysis and detailed journaling. The data from these interviews generated the main themes discussed in this thesis: community connections, places with meaning, and accessing social support services.
Liquefaction during the 4th September 2010 Mw 7.1 Darfield earthquake and large aftershocks in 2011 (Canterbury earthquake sequence, CES) caused severe damage to land and infrastructure within Christchurch, New Zealand. Approximately one third of the total CES-induced financial losses were directly attributable to liq- uefaction and thus highlights the need for local and regional authorities to assess liquefaction hazards for present and future developments. This thesis is the first to conduct paleo-liquefaction studies in eastern Christchurch for the purpose of de- termining approximate return times of liquefaction-inducing earthquakes within the region. The research uncovered evidence for pre-CES liquefaction dated by radiocarbon and cross-cutting relationships as post-1660 to pre-1905. Additional paleo-liquefaction investigations within the eastern Christchurch suburb of Avon- dale, and the northern township of Kaiapoi, revealed further evidence for pre-CES liquefaction. Pre-CES liquefaction in Avondale is dated as post-1321 and pre-1901, while the Kaiapoi features likely formed during three distinct episodes: post-1458 and possibly during the 1901 Cheviot earthquake, post-1297 to pre-1901, and pre-1458. Evaluation of the liquefaction potential of active faults within the Can- terbury region indicates that many faults have the potential to cause widespread liquefaction within Avondale and Kaiapoi. The identification of pre-CES liquefac- tion confirms that these areas have previously liquefied, and indicates that residen- tial development in eastern Christchurch between 1860 and 2005 occurred in areas containing geologic evidence for pre-CES liquefaction. Additionally, on the basis of detailed field and GIS-based mapping and geospatial-statistical analysis, the distribution and severity of liquefaction and lateral spreading within the eastern Christchurch suburb of Avonside is shown in this study to be strongly in uenced by geomorphic and topographic variability. This variability is not currently ac- counted for in site-specific liquefaction assessments nor the simplified horizontal displacement models, and accounts for some of the variability between the pre- dicted horizontal displacements and those observed during the CES. This thesis highlights the potential applications of paleo-liquefaction investigations and ge- omorphic mapping to seismic and liquefaction hazard assessments and may aid future land-use planning decisions.
This thesis examines the closing of Aranui High School in 2016, a low socio-economic secondary school in eastern Christchurch, New Zealand, and reflects on its history through the major themes of innovation and the impact of central government intervention. The history is explored through the leadership of the school principals, and the necessity for constant adaptation by staff to new ways of teaching and learning, driven by the need to accommodate a more varied student population – academically, behaviourally and culturally – than most other schools in wider Christchurch. Several extreme changes, following a neoliberal approach to education policies at a national government level, impacted severely on the school’s ability to thrive and even survive over the 57 years of its existence, with the final impact of the 2010 and 2011 Canterbury earthquakes leading indirectly to Aranui High’s closure. The earthquakes provided the National government with the impetus to advocate for change to education in Christchurch; changes which impacted negatively on many schools in Christchurch, including Aranui High School. The announcement of the closure of Aranui High shocked many staff and students, who were devastated that the school would no longer exist. Aranui High School, Aranui Primary School, Wainoni Primary School and Avondale Primary School were all closed to make way for Haeata Community Campus, a year 1 to 13 school, which was built on the Aranui High site. Aranui High School served the communities of eastern Christchurch for 57 years from 1960 and deserves acknowledgment and remembrance, and my hope is that this thesis will provide a fair representation of the school’s story, including its successes and challenges, while also explaining the reasons behind the eventual closure. This thesis contributes to New Zealand public history and uses mixed research methods to examine Aranui High School’s role as a secondary school in eastern Christchurch. I argue that the closure of Aranui High School in 2016 was an unjustified act by the Ministry of Education.
Christchurch was struck by a 6.3 magnitude earthquake on the 22 February 2011. The quake devastated the city, taking lives and causing widespread damage to the inner city and suburban homes. The central city lost over half its buildings and over 7000 homes were condemned throughout Christchurch. The loss of such a great number of homes has created the requirement for new housing to replace those that were lost. Many of which were located in the eastern, less affluent, suburbs. The response to the housing shortage is the planned creation of large scale subdivisions on the outskirts of the city. Whilst this provides the required housing it creates additional sprawl to a city that does not need it. The extension of Christchurch’s existing suburban sprawl puts pressure on roading and pushes residents further out of the city, creating a disconnection between them. Christchurch’s central city had a very small residential population prior to the earthquakes with very few options for dense inner city living. The proposed rebuild of the inner city calls for a new ‘dense, vibrant and diverse central hub’. Proposing the introduction of new residential units within the central city. However the placement of the low-rise housing in a key attribute of the rebuild, the eastern green ‘Frame’, diminishes its value as open green space. The proposed housing will also be restrictive in its target market and therefore the idea of a ‘vibrant’ inner city is difficult to achieve. This thesis acts as response to the planned rebuild of inner Christchurch. Proposing the creation of a model for inner city housing which provides an alternative option to the proposed housing and existing and ongoing suburban sprawl. The design options were explored through a design-led process were the options were critiqued and developed. The ‘final’ proposal is comprises of three tall towers, aptly named the Triple Towers, which condense the proposed low-rise housing from an 11000 square metre footprint to combined footprint of 1500 square metres. The result is an expansion of the publicly available green space along the proposed eastern frame of the city. The height of the project challenges the height restrictions and is provocative in its proposal and placement. The design explores the relationships between the occupants, the building, the ‘Frame’ and the central city. The project is discussed through an exploration of the architecture of Rem Koolhaas, Renzo Piano and Oscar Niemeyer. Rather than their architecture being taken as a direct influence on which the design is based the discussion revolves around how and why each piece of comparative architecture is relevant to the designs desired outcome.
Oblique-convergent plate collision between the Pacific and Australian plates across the South Island has resulted in shallow, upper crustal earthquake activity and ground surface deformation. In particular the Porters Pass - Amberley Fault Zone displays a complex hybrid zone of anastomosing dextral strike-slip and thrust/reverse faulting which includes the thrust/reverse Lees Valley Fault Zone and associated basin deformation. There is a knowledge gap with respect to the paleoseismicity of many of the faults in this region including the Lees Valley Fault Zone. This study aimed to investigate the earthquake history of the fault at a selected location and the structural and geomorphic development of the Lees Valley Fault Zone and eastern rangefront. This was investigated through extensive structural and geomorphic mapping, GPS field surveying, vertical aerial photo interpretation, analysis of Digital Elevation Models, paleoseismic trenching and optically stimulated luminescence dating. This thesis used a published model for tectonic geomorphology development of mountain rangefronts to understand the development of Lees Valley. Rangefront geomorphology is investigated through analysis of features such as rangefront sinuosity and faceted spurs and indicates the recently active and episodic nature of the uplifted rangefront. Analysis of fault discontinuity, fault splays, distribution of displacement, fault deformation zone and limited exposure of bedrock provided insight into the complex structure of the fault zone. These observations revealed preserved, earlier rangefronts, abandoned and uplifted within the eastern ranges, indicating a basinward shift in focus of faulting and an imbricate thrust wedge development propagating into the footwall of the fault zone and along the eastern ranges of Lees Valley. Fault scarp deformation analysis indicated multiple events have produced the deformation present preserved by the active fault trace in the northern valley. Vertical deformation along this scarp varied with a maximum of 11.5 m and an average of 5 m. Field mapping revealed fan surfaces of various ages have been offset and deformed, likely during the Holocene, based on expected relative surface ages. Geomorphic and structural mapping highlighted the effect of cross-cutting and inherited structures on the Lees Valley Fault, resulting in a step-over development in the centre of the eastern range-bounding trace. Paleoseismic trenching provided evidence of at least two earthquakes, which were constrained to post 21.6 ± 2.3 ka by optically stimulated luminescence dating. Single event displacements (1.48 ± 0.08 m), surface rupture earthquake magnitudes (Mw 6.7 ± 0.1, with potential to produce ≥ 7.0), and a minimum recurrence interval (3.6 ± 0.3 ka) indicated the Lees Valley Fault is an active structure capable of producing significant earthquake events. Results from this study indicate that the Lees Valley Fault Zone accommodates an important component of the Porters Pass - Amberley Fault Zone deformation and confirms the fault as a source of potentially damaging, peak ground accelerations in the Canterbury region. Remnants of previous rangefronts indicate a thrust wedge development of the Lees Valley Fault Zone and associated ranges that can potentially be used as a model of development for other thrust-fault bounded basins.
The Eastern Humps and Leader faults, situated in the Mount Stewart Range in North Canterbury, are two of the ≥17 faults which ruptured during the 2016 MW7.8 Kaikōura Earthquake. The earthquake produced complex, intersecting ground ruptures of these faults and the co-seismic uplift of the Mount Stewart Range. This thesis aims to determine how these two faults accommodated deformation during the 2016 earthquake and how they interact with each other and with pre-existing geological structures. In addition, it aims to establish the most likely subsurface geometry of the fault complex across the Mount Stewart Range, and to investigate the paleoseismic history of the Leader Fault. The Eastern Humps Fault strikes ~240° and dips 80° to 60° to the northwest and accommodated right- lateral – reverse-slip, with up to 4 m horizontal and 2 m vertical displacement in the 2016 earthquake. The strike of the Leader Fault varies from ~155 to ~300°, and dips ~30 to ~80° to the west/northwest, and mainly accommodated left-lateral – reverse-slip of up to 3.5 m horizontal and 3.5 m vertical slip in the 2016 earthquake. On both the Eastern Humps and Leader faults the slip is variable along strike, with areas of low total displacement and areas where horizontal and vertical displacement are negatively correlated. Fault traces with low total displacement reflect the presence of off-fault (distributed) displacement which is not being captured with field measurements. The negative correlation of horizontal and vertical displacement likely indicates a degree of slip partitioning during the 2016 earthquake on both the Eastern Humps and Leader faults. The Eastern Humps and Leader faults have a complex, interdependent relationship with the local bedrock geology. The Humps Fault appears to be a primary driver of ongoing folding and deformation of the local Mendip Syncline and folding of the Mount Stewart Range, which probably began prior to, or synchronous with, initial rupture of The Humps Fault. The Leader Fault appears to use existing lithological weaknesses in the Cretaceous-Cenozoic bedrock stratigraphy to rupture to the surface. This largely accounts for the strong variability on the strike and dip of the Leader Fault, as the geometry of the surface ruptures tend to reflect the strike and dip of the geological strata which it is rupturing through. The Leader Fault may also accommodate some degree of flexural slip in the Cenozoic cover sequence of the Mendip Syncline, contributing to the ongoing growth of the fold. The similarity between topography and uplift profiles from the 2016 earthquake suggest that growth of the Mount Stewart Range has been primarily driven by multiple (>500) discrete earthquakes that rupture The Humps and Leader faults. The spatial distribution of surface displacements across the Mount Stewart Range is more symmetrical than would be expected if uplift is driven primarily by The Humps and Leader faults alone. Elastic dislocation forward models were used to model potential sub-surface geometries and the resulting patterns of deformation compared to photogrammetry-derived surface displacements. Results show a slight preference for models with a steeply southeast-dipping blind fault, coincident with a zone of seismicity at depth, as a ‘backthrust’ to The Humps and Leader faults. This inferred Mount Stewart Fault accommodated contractional strain during the 2016 earthquake and contributes to the ongoing uplift of the Mount Stewart Range with a component of folding. Right-lateral and reverse shear stress change on the Hope Fault was also modelled using Coulomb 3.3 software to examine whether slip on The Humps and Leader faults could transfer enough stress onto the Hope Fault to trigger through-going rupture. Results indicate that during the 2016 earthquake right-lateral shear and reverse stress only increased on the Hope Fault in small areas to the west of the Leader Fault, and similar ruptures would be unlikely to trigger eastward propagating rupture unless the Hope Fault was close to failure prior to the earthquake. Paleoseismic trenches were excavated on the Leader Fault at four locations from 2018 to 2020, revealing near surface (< 4m depth) contractional deformation of Holocene stratigraphy. Three of the trench locations uncovered clear evidence for rupture of the Leader Fault prior to 2016, with fault displacement of near surface stratigraphy being greater than displacement recorded during the 2016 earthquake. Radiocarbon dating of in-situ organic material from two trenches indicate a date of the penultimate earthquake on the Leader Fault within the past 1000 years. This date is consistent with The Humps and Leader faults having ruptured simultaneously in the past, and with multi-fault ruptures involving The Humps, Leader, Hundalee and Stone Jug faults having occurred prior to the 2016 Kaikōura earthquake. Overall, the results contribute to an improved understanding of the Kaikōura earthquake and highlight the importance of detailed structural and paleoseismic investigations in determining controls on earthquake ‘complexity’.
Context of the project: On 4 September 2010, 22 February 2011, 13 June 2011 and 23 December 2011 Christchurch suffered major earthquakes and aftershocks (well over 10,000) that have left the central city in ruins and many of the eastern suburbs barely habitable even now. The earthquakes on 22 February caused catastrophic loss of life with 185 people killed. The toll this has taken on the residents of Christchurch has been considerable, not least of all for the significant psychological impact and disruption it has had on the children. As the process of rebuilding the city commenced, it became clear that the arts would play a key role in maintaining our quality of life during difficult times. For me, this started with the children and the most expressive of all the art forms – music.
The 2010 and 2011 earthquakes in the region of Canterbury, New Zealand caused widespread damage and the deaths of 185 people. Suburbs on the eastern side of Christchurch and in the satellite town of Kaiapoi, 20 kilometres north of Christchurch, were badly damaged by liquefaction. The Canterbury Earthquake Recovery Authority (CERA), a government organisation set up in the wake of the earthquakes, began to systematically zone all residential land in 2011. Based on the possibility for land remediation, 7860 houses in Christchurch and Kaiapoi were zoned red. Those who were in this zone were compensated and had to buy or build elsewhere. The other zone examined within this research – that of TC3 – lies within the green zone. Residents, in this zone, were able to stay in their houses but land was moderately damaged and required site-specific geotechnical investigations. This research sought to understand how residents’ senses of home were impacted by a disaster and the response efforts. Focusing on the TC3 and red zone of the eastern suburbs and the satellite town of Kaiapoi, this study interviewed 29 residents within these zones. The concept of home was explored with the respondents at three scales: home as a household; home as a community; and home as a city. There was a large amount of resistance to the zoning process and the handling of claims by insurance companies and the Earthquake Commission (EQC) after the earthquakes. Lack of transparency and communication, as well as extremely slow timelines were all documented as failings of these agencies. This research seeks to understand how participant’s sense of home changed on an individual level and how it was impacted by outside agencies. Homemaking techniques were also focused on showing that a changed sense of home will impact on how a person interacts with a space.
Surface rupture and slip from the Mw 7.8 2016 Kaikōura Earthquake have been mapped in the region between the Leader and Charwell rivers using field mapping and LiDAR data. The eastern Humps, north Leader and Conway-Charwell faults ruptured the ground surface in the study area. The E-NE striking ‘The Humps’ Fault runs along the base of the Mt Stewart range front, appears to dip steeply NW and intersects the NNW-NNE Leader Fault which itself terminates northwards at the NE striking Conway-Charwell Fault. The eastern Humps Fault is up to the NW and accommodates oblique slip with reverse and right lateral displacement. Net slip on ‘The Humps’ Fault is ≤4 m and produced ≤4 m uplift of the Mt Stewart range during the earthquake. The Leader Fault strikes NNW-NNE with dips ranging from ~10° west to 80° east and accommodated ≤4 m net slip comprising left-lateral and up-to-the-west vertical displacement. Like the Humps west of the study area, surface-rupture of the Leader Fault occurred on multiple strands. The complexity of rupture on the Leader Fault is in part due to the occurrence of bedding-parallel slip within the Cretaceous-Cenozoic sequence. Although the Mt Stewart range front is bounded by ‘The Humps’ Fault, in the study area neither this fault nor the Leader Fault were known to have been active before the earthquake. Fieldwork and trenching investigations are ongoing to characterise the geometry, kinematics and paleoseismic history of the mapped active faults.
Liquefaction-induced lateral spreading during earthquakes poses a significant hazard to the built environment, as observed in Christchurch during the 2010 to 2011 Canterbury Earthquake Sequence (CES). It is critical that geotechnical earthquake engineers are able to adequately predict both the spatial extent of lateral spreads and magnitudes of associated ground movements for design purposes. Published empirical and semi-empirical models for predicting lateral spread displacements have been shown to vary by a factor of <0.5 to >2 from those measured in parts of Christchurch during CES. Comprehensive post- CES lateral spreading studies have clearly indicated that the spatial distribution of the horizontal displacements and extent of lateral spreading along the Avon River in eastern Christchurch were strongly influenced by geologic, stratigraphic and topographic features.
This paper presents an examination of ground motion observations from 20 near-source strong motion stations during the most significant 10 events in the 2010-2011 Canterbury earthquake to examine region-specific systematic effects based on relaxing the conventional ergodic assumption. On the basis of similar site-to-site residuals, surfical geology, and geographical proximity, 15 of the 20 stations are grouped into four sub-regions: the Central Business District; and Western, Eastern, and Northern suburbs. Mean site-to-site residuals for these sub-regions then allows for the possibility of non-ergodic ground motion prediction over these sub-regions of Canterbury, rather than only at strong motion station locations. The ratio of the total non-ergodic vs. ergodic standard deviation is found to be, on average, consistent with previous studies, however it is emphasized that on a site-by-site basis the non-ergodic standard deviation can easily vary by ±20%.
At the conclusion of the 2010 and 2011 Canterbury earthquakes more than 5100 homes had been deemed unsafe for habitation. The land and buildings of these were labelled “red zoned” and are too badly damaged for remediation. These homes have been demolished or are destined for demolition. To assist the red zone population to relocate, central government have offered to ‘buy out’ home owners at the Governmental Value (GV) that was last reviewed in 2007. While generous in the economic context at the time, the area affected was the lowest value land and housing in Christchurch and so there is a capital shortfall between the 2007 property value and the cost of relocating to more expensive properties. This shortfall is made worse by increasing present day values since the earthquakes. Red zone residents have had to relocate to the far North and Western extremities of Christchurch, and some chose to move even further to neighbouring towns or cities. The eastern areas and commercial centres close to the red zone are affected as well. They have lost critical mass which has negatively impacted businesses in the catchments of the Red Zone. This thesis aims to repopulate the suburbs most affected by the abandonment of the red zone houses. Because of the relative scarcity of sound building sites in the East and to introduce affordability to these houses, an alternative method of development is required than the existing low density suburban model. Smart medium density design will be tested as an affordable and appropriate means of living. Existing knowledge in this field will be reviewed, an analysis of what East Christchurch’s key characteristics are will occur, and an examination of built works and site investigations will also be conducted. The research finds that at housing densities of 40 units per hectare, the spatial, vehicle, aesthetic needs of East Christchurch can be accommodated. Centralising development is also found to offer better lifestyle choices than the isolated suburbs at the edges of Christchurch, to be more efficient using existing infrastructure, and to place less reliance on cars. Stronger communities are formed from the outset and for a full range of demographics. Eastern affordable housing options are realised and Christchurch’s ever expanding suburban tendencies are addressed. East Christchurch presently displays a gaping scar of devastated houses that ‘The New Eastside’ provides a bandage and a cure for. Displaced and dispossessed Christchurch residents can be re-housed within a new heart for East Christchurch.
The Canterbury Earthquake Sequence 2010-2011 (CES) induced widespread liquefaction in many parts of Christchurch city. Liquefaction was more commonly observed in the eastern suburbs and along the Avon River where the soils were characterised by thick sandy deposits with a shallow water table. On the other hand, suburbs to the north, west and south of the CBD (e.g. Riccarton, Papanui) exhibited less severe to no liquefaction. These soils were more commonly characterised by inter-layered liquefiable and non-liquefiable deposits. As part of a related large-scale study of the performance of Christchurch soils during the CES, detailed borehole data including CPT, Vs and Vp have been collected for 55 sites in Christchurch. For this subset of Christchurch sites, predictions of liquefaction triggering using the simplified method (Boulanger & Idriss, 2014) indicated that liquefaction was over-predicted for 94% of sites that did not manifest liquefaction during the CES, and under-predicted for 50% of sites that did manifest liquefaction. The focus of this study was to investigate these discrepancies between prediction and observation. To assess if these discrepancies were due to soil-layer interaction and to determine the effect that soil stratification has on the develop-ment of liquefaction and the system response of soil deposits.
It is reported that natural disasters such as earthquakes impact significantly upon survivors’ psychological wellbeing. Little is known however about the impact of disasters upon the professional performance of survivor employees such as teachers. Using a survey research design with an emphasis upon a qualitative data collection, 39 teachers from 6 schools in the eastern suburbs of Christchurch, New Zealand rated the impact of the 2010 and 2011 earthquakes upon their professional performance and 13 volunteered to participate in a follow up focus group interviews. The data collected was interpreted via three theoretical/policy frameworks: the New Zealand Teacher Council mandatory requirements for teachers, the basic psychological needs theory and the inclusive transactional model of stress. Contrary to expectations, relationships with learners, colleagues, learner's whanau (family) and the wider community were on the whole perceived to be positively impacted by the earthquakes, while participation in professional development was regarded in more negative terms. The results indicated that teachers were able to continue (despite some stress reactions) because the basic psychological needs of being a teacher were not disrupted and indeed in some cases were enhanced. A model of teacher performance following a natural disaster is presented. Recommendations and implications (including future research undertakings) arising from the study are indicated. It was noted that given the importance of the school in supporting community recovery following a disaster, support for them and consideration of the role of teachers and the preparation for this should be given some priority.
Coastal and river environments are exposed to a number of natural hazards that have the potential to negatively affect both human and natural environments. The purpose of this research is to explain that significant vulnerabilities to seismic hazards exist within coastal and river environments and that coasts and rivers, past and present, have played as significant a role as seismic, engineering or socio-economic factors in determining the impacts and recovery patterns of a city following a seismic hazard event. An interdisciplinary approach was used to investigate the vulnerability of coastal and river areas in the city of Christchurch, New Zealand, following the Canterbury Earthquake Sequence, which began on the 4th of September 2010. This information was used to identify the characteristics of coasts and rivers that make them more susceptible to earthquake induced hazards including liquefaction, lateral spreading, flooding, landslides and rock falls. The findings of this research are applicable to similar coastal and river environments elsewhere in the world where seismic hazards are also of significant concern. An interdisciplinary approach was used to document and analyse the coastal and river related effects of the Canterbury earthquake sequence on Christchurch city in order to derive transferable lessons that can be used to design less vulnerable urban communities and help to predict seismic vulnerabilities in other New Zealand and international urban coastal and river environments for the future. Methods used to document past and present features and earthquake impacts on coasts and rivers in Christchurch included using maps derived from Geographical Information Systems (GIS), photographs, analysis of interviews from coastal, river and engineering experts, and analysis of secondary data on seismicity, liquefaction potential, geology, and planning statutes. The Canterbury earthquake sequence had a significant effect on Christchurch, particularly around rivers and the coast. This was due to the susceptibility of rivers to lateral spreading and the susceptibility of the eastern Christchurch and estuarine environments to liquefaction. The collapse of river banks and the extensive cracking, tilting and subsidence that accompanied liquefaction, lateral spreading and rock falls caused damage to homes, roads, bridges and lifelines. This consequently blocked transportation routes, interrupted electricity and water lines, and damaged structures built in their path. This study found that there are a number of physical features of coastal and river environments from the past and the present that have induced vulnerabilities to earthquake hazards. The types of sediments found beneath eastern Christchurch are unconsolidated fine sands, silts, peats and gravels. Together with the high water tables located beneath the city, these deposits made the area particularly susceptible to liquefaction and liquefaction-induced lateral spreading, when an earthquake of sufficient size shook the ground. It was both past and present coastal and river processes that deposited the types of sediments that are easily liquefied during an earthquake. Eastern Christchurch was once a coastal and marine environment 6000 years ago when the shoreline reached about 6 km inland of its present day location, which deposited fine sand and silts over this area. The region was also exposed to large braided rivers and smaller spring fed rivers, both of which have laid down further fine sediments over the following thousands of years. A significant finding of this study is the recognition that the Canterbury earthquake sequence has exacerbated existing coastal and river hazards and that assessments and monitoring of these changes will be an important component of Christchurch’s future resilience to natural hazards. In addition, patterns of recovery following the Canterbury earthquakes are highlighted to show that coasts and rivers are again vulnerable to earthquakes through their ability to recovery. This city’s capacity to incorporate resilience into the recovery efforts is also highlighted in this study. Coastal and river areas have underlying physical characteristics that make them increasingly vulnerable to the effects of earthquake hazards, which have not typically been perceived as a ‘coastal’ or ‘river’ hazard. These findings enhance scientific and management understanding of the effects that earthquakes can have on coastal and river environments, an area of research that has had modest consideration to date. This understanding is important from a coastal and river hazard management perspective as concerns for increased human development around coastlines and river margins, with a high seismic risk, continue to grow.
The Christchurch earthquakes brought to an abrupt halt a process of adaptive reuse and gentrification that was underway in the south eastern corner of the central business district. The retail uses that were a key to the success of this area pre-earthquake could be characterised as small, owner operated, quirky, bohemian, chaotic and relatively low rent. This research reports on the progress of a long term, comprehensive case study that follows the progress of these retailers both before and after the earthquakes. Findings include the immediate post-earthquake intentions to resume business in the same location as soon as possible were thwarted by government imposed cordons of the CBD that were only lifted nearly three years later. But, businesses were resilient and generally reinvented themselves quickly in alternative suburban locations where government “rebuild” restrictions were absent. It remains to be seen if this type of retail will ever return to the CBD as government imposed plans and the rents demanded for retail space in new buildings appear to preclude small owner-operated businesses.
This project was initiated by ENGEO Limited and KiwiRail Holdings Limited to assess the stability of Slovens Creek Viaduct (specifically its western abutment) and a 3km section of rail corridor between Slovens Creek Viaduct and Avoca on the Midland Line (MDL). Commonly known as the scenic TranzAlpine rail journey (through Arthurs Pass National Park) the MDL connects Greymouth to Christchurch via Rolleston, where the MDL meets the Main South Line into Christchurch. The project area is approximately 40km southeast of Arthurs Pass Township, in the eastern extension of the Castle Hill Basin which is part of the Waimakariri Catchment and Canterbury Foothills. The field area is underlain by Rakaia Terrane, which is part of the Torlesse Composite Terrane forming the basement rock unit for the field area. Cretaceous-Tertiary rocks of the Castle Hill Basin overlie the basement strata and record a transgression-regression sequence, as well as mid-Oligocene submarine volcanism. The stratigraphic sequence in the Castle Hill Basin, and its eastern extension to Avoca, comprises two formations of the Eyre group, the older Broken River Formation and the younger Iron Creek Formation. Deep marine Porter Group limestones, marls, and tuffs of Oligocene age succeed the Iron Creek Formation of the Eyre Group, and probably records the maximum of the transgression. The Enys Formation lies disconformably on the Porter Group and is overlain unconformably by Late Pleistocene glacifluvial and glacial deposits. The Tertiary strata in the Slovens-Avoca rail corridor are weak, and the clay-rich tuff derived from mid-Oligocene volcanism is particularly prone to slaking. Extensive mapping carried out for this project has identified that some 90 percent of the surface along the length of the Slovens-Avoca corridor has been subject to mass movement. The landslides of the Slovens-Avoca rail corridor are clearly younger than the Last Glaciation, and Slovens Creek has been downcutting, with associated faulting and uplift, to form the present day geomorphology of the rail corridor. Deep-seated landslides in the rail corridor extend to Slovens Creek, locally deflecting the stream course, and a generic ground failure model for the rail corridor has been developed. Exploratory geotechnical investigations, including core drilling, installation of an inclinometer and a piezometer, enabled the construction of a simple ground model and cross section for the Slovens Creek Viaduct western abutment. Limit-equilibrium and pseudo-static slope stability analyses using both circular and block critical slip surface search methods were applied to the ground model for the western abutment of Slovens Creek Viaduct. Piezometric and strength data obtained during laboratory testing of core material have been used to constrain the western abutment stability assessment for one representative section line (C-C’). Prior to pseudo-static sensitivity analyses peak ground acceleration (PGA) for various Ultimate Limit State (ULS) design return periods, defined by an equation given in NZS1170.5:2004, were calculated and have been used as a calibration technique to find and compare specific PGA values for pseudo-static analyses in the Slovens Creek Viaduct area. The main purpose has been to provide an indication of how railway infrastructure could be affected by seismic events of various return periods defined by ULS design standards for the area. Limit equilibrium circular slip surface search methods, both grid search and auto refine search, indicated the slope is stable with a FoS greater than 1.0 returned from each, although one particular surface returned the lowest FoS in each. This surface is in the lower portion of the slope, adjacent to Slovens Stream and northeast of the MDL. As expected, pseudo-static analyses returned a lower FoS overall when compared to limit equilibrium analyses. The PGA analyses suggest that partial ground failure at the Slovens Creek Viaduct western abutment could occur in a 1 in 25-year return period event within materials on the slower slope beyond the immediate rail corridor. A ULS (1 in 500-year) event in the Slovens Creek Viaduct area would likely produce a PGA of ~0.9g, and the effects on the western abutment and rail infrastructure would most likely be catastrophic. Observed ground conditions for the western abutment of the Slovens Creek Viaduct suggest there is no movement within the landslide at depth within the monitoring timeframe of this project (22 May 2015 – 4 August 2015). Slope stability monitoring is recommended to be continued in two parts: (1) the inclinometer in BH1 is to be monitored on a six monthly basis for one year following completion of this thesis, and then annually unless ground movements become evident; and (2) surface movement monitoring should be installed using a fixed datum on the stable eastern abutment. Long-term stability management strategies for the Slovens Creek Viaduct western abutment are dependent upon future observed changes and ongoing monitoring. Hazard and risk assessment using the KiwiRail Qualitative Risk Assessment Framework (QRA) is recommended, and if slope stability becomes problematic for operation of the Midland Line consideration should be given to deep slope drainage. In the event of a large magnitude or high PGA earthquake all monitoring should be reviewed.
Detailed studies on the sediment budget may reveal valuable insights into the successive build-up of the Canterbury Plains and their modification by Holocene fluvialaction connected to major braided rivers. Additionally, they bear implications beyond these fluvial aspects. Palaeoseismological studies claim to have detected signals of major Alpine Fault earthquakes in coastal environments along the eastern seaboard of the South Island (McFadgen and Goff, 2005). This requires high connectivity between the lower reaches of major braided rivers and their mountain catchments to generate immediate significant sediment pulses. It would be contradictory to the above mentioned hypothesis though. Obtaining better control on sediment budgets of braided rivers like the Waimakariri River will finally add significant value to multiple scientific and applied topics like regional resource management. An essential first step of sediment budget studies Is to systematically map the geomorphology, conventionally in the field and/or using remote-sensing applications, to localise, genetically identify, and classify landforms or entire toposequences of the area being investigated. In formerly glaciated mountain environments it is also indispensable to obtain all available chronological information supporting subsequent investigations.
Successful urban regeneration projects generate benefits that are realised over a much longer timeframe than normal market developments and benefits well beyond those that can be uplifted by a market developer. Consequently there is substantial evidence in the literature that successful place-making and urban regeneration projects are usually public-private partnerships and involve a funder, usually local or central government, willing to contribute ‘patient’ capital. Following the 2010 and 2011 earthquakes that devastated the centre of Christchurch, there was an urgent need to rebuild and revitalise the heart of the city, and increasing the number of people living in or near the city centre was seen as a key ingredient of that. In October 2010, an international competition was launched to design and build an Urban Village, a project intended to stimulate renewed residential development in the city. The competition attracted 58 entrants from around world, and in October 2013 the winning team was chosen from four finalists. However the team failed to secure sufficient finance, and in November 2015 the Government announced that the development would not proceed. The Government was unwilling or unable to recognise that an insistence on a pure market approach would not deliver the innovative sustainable village asked for in the competition brief, and failed to factor in the opportunity cost to government, local government, local businesses and the wider Christchurch community of delaying by many years the residential development of the eastern side of the city. As a result, the early vision of the vitality that a thriving residential neighbourhood would bring to the city has not yet been realised.
The Covid-19 pandemic has brought to the foreground the importance of social connectedness for wellbeing, at the individual, community and societal level. Within the context of the local community, pro-connection facilities are fundamental to foster community development, resilience and public health. Through identifying the gap in social connectedness literature for Māori, this has created space for new opportunities and to reflect on what is already occurring in Ōtautahi. It is well documented that Māori experience unequal societal impacts across all health outcomes. Therefore, narrowing the inequities between Māori and non-Māori across a spectrum of dimensions is a priority. Evaluating the #WellconnectedNZ project, which explores the intersections between social connection and wellbeing is one way to trigger these conversations. This was achieved by curating a dissimilar set of community pro-connection facilities and organizing them into a Geographic Information System (GIS). Which firstly involved, the collecting and processing of raw data, followed by spatial analysis through creating maps, this highlighted the alignment between the distribution of places, population and social data. Secondly, statistical analysis focusing on the relationship between deprivation and accessibility. Finally, semi-structured interviews providing perceptions of community experience. This study describes findings following a kaupapa Māori research approach. Results demonstrated that, in general some meshblocks in Ōtautahi benefit from a high level of accessibility to pro-connection facilities; but with an urban-rural gradient (as is expected, further from the central business district (CBD) are less facilities). Additionally, more-deprived meshblocks in the Southern and Eastern suburbs of Christchurch have poorer accessibility, suggesting underlying social and spatial inequalities, likely exacerbated by Covid-19 and the Christchurch earthquakes. In this context, it is timely to (re)consider pro-connection places and their role in the development of social infrastructure for connected communities, in the community facility planning space. ‘We are all interwoven, we just need to make better connections’.
The 2010-2011 Canterbury Earthquakes brought devastation to the city of Christchurch and has irrevocably affected the lives of the city’s residents. Years after the conclusion of these earthquakes, Christchurch and its residents are well on the path to recovery. Crime has proven an ongoing topic of discussion throughout this period, with news reports of increased burglary and arson in areas left largely abandoned by earthquake damage, and a rise in violent crime in suburban areas of Christchurch. Following the body of research that has considered the reaction of crime to natural disasters, this research has sought to comprehensively examine and understand the effects that the Canterbury Earthquakes had on crime. Examining Christchurch-wide offending, crime rates fell over the study period (July 2008 to June 2013), with the exception of domestic violence. Aside from a momentary increase in burglary in the days immediately following the Christchurch Earthquake, crime rates (as of 2013) have remained largely below pre-earthquake levels. Using Dual Kernel Density Estimation Analysis, a distinct spatial change in pre-earthquake crime hotspots was observed. These changes included an enormous decrease in central city offences, a rise in burglary in the eastern suburbs, and an increase in assault in areas outside of the central city. Logistic regression analysis, using a time-compensated dependent variable, identified a number of statistically-significant relationships between per CAU crime rate change and factors measuring socio-demographic characteristics, community cohesion, and the severity of disaster effects. The significance of these findings was discussed using elements of Social Disorganisation Theory, Routine Activity Theory, and Strain Theory. Consistent with past findings, social order was largely maintained following the Canterbury Earthquakes, with suggestion that increased collective efficacy and therapeutic communities had a negative influence on crime in the post-earthquake period. Areas of increased burglary and assault were associated with large population decreases, suggesting a link with the dissolution of communities and the removal of their inherent informal guardianship. Though observed, the increase in domestic violence was not associated with most neighbourhood-level variables. Trends in crime after the Canterbury Earthquakes were largely consistent with past research, and the media’s portrayal.
In the aftermath of the 2010-2011 Canterbury Earthquake Sequence (CES), the location of Christchurch-City on the coast of the Canterbury Region (New Zealand) has proven crucial in determining the types of- and chains of hazards that impact the city. Very rapidly, the land subsidence of up to 1 m (vertical), and the modifications of city’s waterways – bank sliding, longitudinal profile change, sedimentation and erosion, engineered stop-banks… - turned rainfall and high-tides into unprecedented floods, which spread across the eastern side of the city. Within this context, this contribution presents two modeling results of potential floods: (1) results of flood models and (2) the effects of further subsidence-linked flooding – indeed if another similar earthquake was to strike the city, what could be the scenarios of further subsidence and then flooding. The present research uses the pre- and post-CES LiDAR datasets, which have been used as the boundary layer for the modeling. On top of simple bathtub model of inundation, the river flood model was conducted using the 2-D hydrodynamic code NAYS-2D developed at the University of Hokkaido (Japan), using a depth-averaged resolution of the hydrodynamic equations. The results have shown that the area the most at risk of flooding are the recent Holocene sedimentary deposits, and especially the swamplands near the sea and in the proximity of waterways. As the CES drove horizontal and vertical displacement of the land-surface, the surface hydrology of the city has been deeply modified, increasing flood risks. However, it seems that scientists and managers haven’t fully learned from the CES, and no research has been looking at the potential future subsidence in further worsening subsidence-related floods. Consequently, the term “coastal quake”, coined by D. Hart is highly topical, and most especially because most of our modern cities and mega-cities are built on estuarine Holocene sediments.
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.
Lincoln University was commissioned by the Avon-Otakaro Network (AvON) to estimate the value of the benefits of a ‘recreation reserve’ or ‘river park’ in the Avon River Residential Red Zone (ARRRZ). This research has demonstrated significant public desire and support for the development of a recreation reserve in the Avon River Residential Red Zone. Support is strongest for a unique natural environment with native fauna and flora, healthy wetlands and rivers, and recreational opportunities that align with this vision, such as walking, cycling and water-based sporting and leisure activities. The research also showed support for a reserve that promotes and enables community interaction and wellbeing, and is evident in respondents’ desires for community gardens, regular festivals and markets, and the physical linking of the CBD with eastern suburbs through a green corridor. There is less support for children’s playgrounds, sports fields or open grassed areas, all of which could be considered as more typical of an urban park development. Benefits (willing to pay) to Christchurch residents (excluding tourists) of a recreation reserve could be as high as $35 million each year. Savings to public health costs could be as high as $50.3 million each year. The incorporation or restoration of various ecosystems services, including water quality improvements, flood mitigation and storm water management could yield a further $8.8 million ($19, 600) per hectare/year at 450 ha). Combined annual benefits of a recreational reserve in the ARRRZ are approximately $94.1 million per annum but this figure does not include potentially significant benefits from, for example, tourism, property equity gains in areas adjacent to the reserve, or the effects of economic rejuvenation in the East. Although we were not able to provide costing estimates for park attributes, this study does make available the value of benefits, which can be used as a guide to the scope of expenditure on development of each park attribute.
The whare whakairo or traditional Māori meeting house plays an important part in Māori society and identity. These whare tell the tale of their origin, and in so doing, the origins of their people. The analysis of the meeting house, the histories expressed in its decorative carvings and structural elements are inextricably linked with and dependent upon the structure of the world created by myth and the Māori worldview. However, due to the deleterious effects of colonisation, the art of wood carving and associated architectural practices - central to Māori identity, suffered decline in many parts of the country, leading to the decline of Māori culture and identity. Sir Apirana Ngata instigated the National Institute of Māori Arts and Crafts to resurrect the dying art of Māori carving and carved houses would be a catalyst for the restoration of Māori culture throughout the country. Ngata saw these whare whakairo as being the heart of Māori communities by establishing a renewed sense of belonging and identification with space for Māori, through the telling of tribal histories and emphasising key geographical features. New threats in the form of global hegemony and urbanisation have further impacted on Māori notions of identity, creating a generation of displaced urban Māori youth. This research proposes to establish an architectural response to capture displaced Māori youth through the resurrection of the Māori carving school and return to them the lost stories of their cultural history and identity. This program will be developed within the complex challenges that exist within post-earthquake Ōtautahi/Christchurch, where many have lost homes and livelihoods, especially Māori youth in the Eastern Suburbs. The building elements of the proposed Māori carving school give reference to the historio-cultural features of the original Ōtautahi/Christchurch landscape that are situated in tribal song and myth. It is envisioned that the development of a Māori carving school will help restore Māori identity and a renewed sense of belonging, and allow for the telling of this generations stories through traditional narratives.
For the people of Christchurch and its wider environs of Canterbury in New Zealand, the 4th of September 2010 earthquake and the subsequent aftershocks were daunting. To then experience a more deadly earthquake five months later on the 22nd of February 2011 was, for the majority, overwhelming. A total of 185 people were killed and the earthquake and continuing aftershocks caused widespread damage to properties, especially in the central city and eastern suburbs. A growing body of literature consistently documents the negative impact of experiencing natural disasters on existing psychological disorders. As well, several studies have identified positive coping strategies which can be used in response to adversities, including reliance on spiritual and cultural beliefs as well as developing resilience and social support. The lifetime prevalence of severe mental health disorders such as posttraumatic stress disorder (PTSD) occurring as a result of experiencing natural disasters in the general population is low. However, members of refugee communities who were among those affected by these earthquakes, as well as having a past history of experiencing traumatic events, were likely to have an increased vulnerability. The current study was undertaken to investigate the relevance to Canterbury refugee communities of the recent Canterbury Earthquake Recovery Authority (CERA) draft recovery strategy for Christchurch post-earthquakes. This was accomplished by interviewing key informants who worked closely with refugee communities. These participants were drawn from different agencies in Christchurch including Refugee Resettlement Services, the Canterbury Refugee Council, CERA, and health promotion and primary healthcare organisations, in order to obtain the views of people who have comprehensive knowledge of refugee communities as well as expertise in local mainstream services. The findings from the semi-structured interviews were analysed using qualitative thematic analysis to identify common themes raised by the participants. The key informants described CERA’s draft recovery strategy as a significant document which highlighted the key aspects of recovery post disaster. Many key informants identified concerns regarding the practicality of the draft recovery strategy. For the refugee communities, some of those concerns included the short consultation period for the implementation phase of the draft recovery strategy, and issues surrounding communication and collaboration between refugee agencies involved in the recovery. This study draws attention to the importance of communication and collaboration during recovery, especially in the social reconstruction phase following a disaster, for all citizens but most especially for refugee communities.
Geologic phenomena produced by earthquake shaking, including rockfalls and liquefaction features, provide important information on the intensity and spatiotemporal distribution of earthquake ground motions. The study of rockfall and liquefaction features produced in contemporary well- instrumented earthquakes increases our knowledge of how natural and anthropogenic environments respond to earthquakes and improves our ability to deduce seismologic information from analogous pre-contemporary (paleo-) geologic features. The study of contemporary and paleo- rockfall and liquefaction features enables improved forecasting of environmental responses to future earthquakes. In this thesis I utilize a combination of field and imagery-based mapping, trenching, stratigraphy, and numerical dating techniques to understand the nature and timing of rockfalls (and hillslope sedimentation) and liquefaction in the eastern South Island of New Zealand, and to examine the influence that anthropogenic activity has had on the geologic expressions of earthquake phenomena. At Rapaki (Banks Peninsula, NZ), field and imagery-based mapping, statistical analysis and numerical modeling was conducted on rockfall boulders triggered by the fatal 2011 Christchurch earthquakes (n=285) and compared with newly identified prehistoric (Holocene and Pleistocene) boulders (n=1049) deposited on the same hillslope. A significant population of modern boulders (n=26) travelled farther downslope (>150 m) than their most-travelled prehistoric counterparts, causing extensive damage to residential dwellings at the foot of the hillslope. Replication of prehistoric boulder distributions using 3-dimensional rigid body numerical models requires the application of a drag-coefficient, attributed to moderate to dense slope vegetation, to account for their spatial distribution. Radiocarbon dating provides evidence for 17th to early 20th century deforestation at the study site during Polynesian and European colonization and after emplacement of prehistoric rockfalls. Anthropocene deforestation enabled modern rockfalls to exceed the limits of their prehistoric predecessors, highlighting a shift in the geologic expression of rockfalls due to anthropogenic activity. Optical and radiocarbon dating of loessic hillslope sediments in New Zealand’s South Island is used to constrain the timing of prehistoric rockfalls and associated seismic events, and quantify spatial and temporal patterns of hillslope sedimentation including responses to seismic and anthropogenic forcing. Luminescence ages from loessic sediments constrain timing of boulder emplacement to between ~3.0 and ~12.5 ka, well before the arrival of Polynesians (ca AD 1280) and Europeans (ca AD 1800) in New Zealand, and suggest loess accumulation was continuing at the study site until 12-13 ka. Large (>5 m3) prehistoric rockfall boulders preserve an important record of Holocene hillslope sedimentation by creating local traps for sediment aggradation and upbuilding soil formation. Sediment accumulation rates increased considerably (>~10 factor increase) following human arrival and associated anthropogenic burning of hillslope vegetation. New numerical ages are presented to place the evolution of loess-mantled hillslopes in New Zealand’s South Island into a longer temporal framework and highlight the roles of earthquakes and humans on hillslope surface process. Extensive field mapping and characterization for 1733 individual prehistoric rockfall boulders was conducted at Rapaki and another Banks Peninsula site, Purau, to understand their origin, frequency, and spatial and volumetric distributions. Boulder characteristics and distributions were compared to 421 boulders deposited at the same sites during the 2010-2011 Canterbury earthquake sequence. Prehistoric boulders at Rapaki and Purau are comprised of two dominant lithofacies types: volcanic breccia and massive (coherent) lava basalt. Volcanic breccia boulders are found in greatest abundance (64-73% of total mapped rockfall) and volume (~90-96% of total rockfall) at both locations and exclusively comprise the largest boulders with the longest runout distances that pose the greatest hazard to life and property. This study highlights the primary influence that volcanic lithofacies architecture has on rockfall hazard. The influence of anthropogenic modifications on the surface and subsurface geologic expression of contemporary liquefaction created during the 2010-2011 Canterbury earthquake sequence (CES) in eastern Christchurch is examined. Trench observations indicate that anthropogenic fill layer boundaries and the composition/texture of discretely placed fill layers play an important role in absorbing fluidized sand/silt and controlling the subsurface architecture of preserved liquefaction features. Surface liquefaction morphologies (i.e. sand blows and linear sand blow arrays) display alignment with existing utility lines and utility excavations (and perforated pipes) provided conduits for liquefaction ejecta during the CES. No evidence of pre-CES liquefaction was identified within the anthropogenic fill layers or underlying native sediment. Radiocarbon dating of charcoal within the youngest native sediment suggests liquefaction has not occurred at the study site for at least the past 750-800 years. The importance of systematically examining the impact of buried infrastructure on channelizing and influencing surface and subsurface liquefaction morphologies is demonstrated. This thesis highlights the importance of using a multi-technique approach for understanding prehistoric and contemporary earthquake phenomena and emphasizes the critical role that humans play in shaping the geologic record and Earth’s surface processes.
<jats:p>Social and natural capital are fundamental to people’s wellbeing, often within the context of local community. Developing communities and linking people together provide benefits in terms of mental well-being, physical activity and other associated health outcomes. The research presented here was carried out in Christchurch - Ōtautahi, New Zealand, a city currently re-building, after a series of devastating earthquakes in 2010 and 2011. Poor mental health has been shown to be a significant post-earthquake problem, and social connection has been postulated as part of a solution. By curating a disparate set of community services, activities and facilities, organised into a Geographic Information Systems (GIS) database, we created i) an accessibility analysis of 11 health and well-being services, ii) a mobility scenario analysis focusing on 4 general well-being services and iii) a location-allocation model focusing on 3 primary health care and welfare location optimisation. Our results demonstrate that overall, the majority of neighbourhoods in Christchurch benefit from a high level of accessibility to almost all the services; but with an urban-rural gradient (the further away from the centre, the less services are available, as is expected). The noticeable exception to this trend, is that the more deprived eastern suburbs have poorer accessibility, suggesting social inequity in accessibility. The findings presented here show the potential of optimisation modelling and database curation for urban and community facility planning purposes.</jats:p>
