Ongoing climate change triggers increasing temperature and more frequent extreme events which could limit optimal performance of haliotids, affect their physiology and biochemistry as well as influencing their population structure. Haliotids are a valuable nearshore fishery in a number of countries and many are showing a collapse of stocks because of overexploitation, environmental changes, loss of habitat, and disease. The haliotid in New Zealand commonly referred to as the blackfoot pāua (Haliotis iris) contribute a large and critical cultural, recreational and economic resource. Little was known about pāua responses to increasing temperature and acute environmental factors, as well as information about population size structure in Kaikoura after the earthquake 2016 and in Banks Peninsula. The aims of this study were to investigate the effects of temperature on scope for growth (SfG); physiological and biochemical responses of pāua subjected to different combined stressors including acute temperature, acute salinity and progressive hypoxia; and describe population size structure and shell morphology in different environments in Kaikoura and Banks Peninsula. The main findings of the present study found that population size structures of pāua were site-specific, and the shell length and shell height ratio of 3.25 could distinguish between stunted and non-stunted populations. The study found that high water temperature resulted in a reduction in absorbed energy from food, an increase in respiration energy, and ammonia excretion energy. Surveys were conducted at six study sites around the Canterbury Region over three years in order to better understand the population size structure and shell morphology of pāua. The findings found that the population size structure at 6 sites differed. Both juveniles and adults were found in intertidal areas at five sites. However, at Cape Three Points, pāua were found only in subtidal zones. One of the sites, Little Port Cooper, had a stunted population where only two pāua reached 125 mm in length over three years. In addition, most pāua in Little Port Cooper and Cape Three Points were adults, while Seal Reef had mostly juveniles. Wakatu Quay and Omihi had a full size range of pāua. Oaro population was dominated with juveniles and sub-adults. Recruitment and growth of pāua were successful after the earthquake in 2016. Research into pāua shell morphologies also determined that shell dimensions differed between sites. The relationships of shell length to shell width were linear and the relationship of shell length to shell height was curvilinear. Interestingly, SL:SH ratio of 3.25 is able to be used to identify stunted and non-stunted populations for pāua larger than 90 mm in length. Little Port Cooper was a stunted population with mean SL:SH ratio being 3.16. In the laboratory, scope for growth of pāua was investigated at four different temperatures of 12oC, 15oC, 18oC and 21oC over four weeks’ acclimation. The current study has found that SfG of pāua highly depended on temperature. Absorbed energy and respiration energy accounted for the highest proportion of the SfG of pāua. The respiration energy of pāua accounted for approximately 36%, 40%, 49% and 69% of the absorbed energy at 12°C, 15°C, 18°C and 21°C, respectively. The pāua at all acclimation temperatures had a positive scope for growth. The study suggested that the SfG was highest at 15°C, while the value at 21°C was the lowest. However, SfG at 18°C and 21°C decreased after 14 days of acclimation. Because of maintaining almost unchanged oxygen consumption over four weeks’ acclimation, pāua showed their poor abilities to acclimate to an increase in temperature. Therefore, they may be more vulnerable in future warming scenarios. The physiological and biochemical responses of pāua toward different combined stressors included three experiments. In terms of the acute temperature experiment, pāua were acclimated at 12oC, 15oC, 18oC or 21oC for two weeks before stepwise exposure to four temperatures of 12oC, 15oC, 18oC and 21oC every 4 hours. The acute salinity change, pāua were acclimated at 12oC, 15oC or 18oC over two weeks. Pāua were then exposed to a stepwise decrease of salinity of 2‰ every two hours from 34 – 22‰. Regarding the declining oxygen level, pāua were acclimated at 15 oC or 18oC for two weeks before exposure to one of four temperatures at 12oC, 15oC, 18oC or 21oC in one hour. After that acute progressive hypoxia was studied in closed respirometers for around six hours. The findings showed that there were interactions between combined stressors, affecting physiology of pāua (metabolism and heart rate). This suggests that environmental factors do not have a separate effect, but they also have interactions that enhance negative effects on pāua. Also, both oxygen uptake and heart rate responded quickly to temperature change and increased with rising temperature. On the other hand, oxygen uptake and heart rate decreased with reducing salinity and progressive hypoxia (before critical oxygen tension - Pcrit). Pcrit over four acute temperature exposures, ranged between 30.2 and 80.0 mmHg, depending on the exposure temperature. Acclimation temperature, combined with acute temperature, salinity or hypoxia stress affected the biochemistry of pāua. Pāua are osmoconformers so decreased salinity resulted in reducing haemolymph ionic concentration and increasing body volume. They were hypo-ionic with respect to sodium and potassium over the salinity ranges of 34 - 22‰. Haemocyanin accounts for a large pecentage of haemolymph protein, so trends of protein followed haemocyanin. Pāua tended to store oxygen in haemocyanin under extreme salinity stress at 22‰ and extreme hypoxia around 10 mmHg, rather than in oxygen transport. In conclusion, pāua at different sites had different population structures and morphologies. Pāua are sensitive to environmental stressors. They consumed more oxygen at high temperatures because they do not have thermal acclimation capacity. They are also osmoconformers with haemolymph sodium and potassium decreasing with salinity medium. Under progressive hypoxia, pāua could regulate oxygen and heart rate until Pcrit depending on temperature. Acute environmental changes also disturbed haemolyph parameters. 12°C and 15°C could be in the range of optimal temperature with higher SfG and less stress when exposed to acute environmental changes. Meanwhile long term exposure to 21°C is likely to be outside of the optimal range for the pāua. With ongoing climate change, pāua populations are more vulnerable so conservation is necessary. The research contributes to improving fishery management, providing insights into different environmental stressors affecting the energy demand and physiological and biochemical responses of pāua. It also allow to predicting the growth patterns and responses of pāua to adapt to climate change.
On 22 February 2011, Ōtautahi Christchurch was struck by a devastating earthquake. The city was changed forever: lives were lost, buildings destroyed and much of the city’s infrastructure needed to be repaired or replaced. One of the unexpected outcomes of the process of recovery was the volume of archaeological work that was carried out in the city, including the substantial amount of buildings archaeology that was undertaken (that is, recording standing buildings prior to and during their demolition, using archaeological techniques). Amongst the numerous buildings recorded in this way were 101 houses from across the city (but concentrated in those areas hit hardest by the earthquakes), built between 1850 and 1900. This work yielded a wealth of data about what houses in the city looked like in the nineteenth century. It is this data that forms the core of my thesis, providing an opportunity to examine the question of what life was like in nineteenth century Christchurch through these houses and the people who built them. Christchurch was founded in 1850 by European settlers, most of whom were English. These people came to New Zealand to build a better life for themselves and their families. For many of them, this ‘better life’ included the possibility of owning their own home and, in some instances, building that house (or at least, commissioning its construction). The buildings archaeology data collected following the Canterbury earthquakes enabled a detailed analysis of what houses in the city looked like in the nineteenth century – their form, and both their external and internal appearance – and how this changed as the century progressed. A detailed examination of the lives of those who built 21 of the houses enabled me to understand why each house looked the way it did, and how the interplay of class, budget and family size and expectations (amongst other factors) shaped each house. It is through these life stories that more about life in Christchurch in the nineteenth century was revealed. These are stories of men and women, of success and failure, of businesses and bankruptcies. There are themes that run through the stories: class, appearances, death, religion, gender, improvement. Just as importantly, though, they reveal the everyday experiences of people as they set about building a new city. Thus, through the archaeology of the houses and the history of the people who built them, an earthquake has revealed more about life in nineteenth century Christchurch, as well as providing the means for a deeper understanding of the city’s domestic architecture.
People aged 65 years and older are the fastest growing age group in New Zealand. By the mid-2070s, there are predictions that this age group is likely to comprise approximately one third of the population. Older people are encouraged to stay in their own homes within their community for as long as possible with support to encourage the extension of ageing in place. Currently around 14% of those aged 75 years or older, make the move into retirement villages. This is expected to increase. Little is known by retirement villages about the wellbeing and health of those who decide to live independently in these facilities. Predicting the need for a continuum of care is challenging. This research measured the wellbeing and health of older adults. It was situated in a critical realist paradigm, overlaid with an empathetic axiology. A focused literature review considered the impact on wellbeing from the aspects of living place, age, gender, health status and the 2010/2011 Canterbury earthquakes. Longitudinal studies used the Enlightenment Scale and the interRAI Community Health Assessment (CHA) to measure the wellbeing and health of one group of residents (n=120) living independently in one retirement village in Canterbury, New Zealand. The research was extended to incorporate two cross-section studies when initial results for wellbeing were found to be higher than anticipated. These additional studies included participants living independently from other retirement villages (n=115) and those living independently within the community (n=354). A total of 589 participants, aged 65 – 97 years old, completed the Enlightenment Scale across the four studies. Across the living places, wellbeing continued to significantly improve with age. The Enlightenment Scale was a useful measure of wellbeing with older adults. Participants in the longitudinal studies largely maintained a relatively good health status, showing little change over the study period of 15 months. Predictions for the need for a move to supportive care were not able to be made using the CHA. The health status of participants did not influence their level of wellbeing. The key finding of note is that the wellbeing score of older adults increases by 1.27 points per year, using the Enlightenment Scale, irrespective of where they live.
Rapid, reliable information on earthquake-affected structures' current damage/health conditions and predicting what would happen to these structures under future seismic events play a vital role in accelerating post-event evaluations, leading to optimized on-time decisions. Such rapid and informative post-event evaluations are crucial for earthquake-prone areas, where each earthquake can potentially trigger a series of significant aftershocks, endangering the community's health and wealth by further damaging the already-affected structures. Such reliable post-earthquake evaluations can provide information to decide whether an affected structure is safe to stay in operation, thus saving many lives. Furthermore, they can lead to more optimal recovery plans, thus saving costs and time. The inherent deficiency of visual-based post-earthquake evaluations and the importance of structural health monitoring (SHM) methods and SHM instrumentation have been highlighted within this thesis, using two earthquake-affected structures in New Zealand: 1) the Canterbury Television (CTV) building, Christchurch; 2) the Bank of New Zealand (BNZ) building, Wellington. For the first time, this thesis verifies the theoretically- and experimentally validated hysteresis loop analysis (HLA) SHM method for the real-world instrumented structure of the BNZ building, which was damaged severely due to three earthquakes. Results indicate the HLA-SHM method can accurately estimate elastic stiffness degradation for this reinforced concrete (RC) pinched structure across the three earthquakes, which remained unseen until after the third seismic event. Furthermore, the HLA results help investigate the pinching effects on the BNZ building's seismic response. This thesis introduces a novel digital clone modelling method based on the robust and accurate SHM results delivered by the HLA method for physical parameters of the monitored structure and basis functions predicting the changes of these physical parameters due to future earthquake excitations. Contrary to artificial intelligence (AI) based predictive methods with black-box designs, the proposed predictive method is entirely mechanics-based with an explicitly-understandable design, making them more trusted and explicable to stakeholders engaging in post-earthquake evaluations, such as building owners and insurance firms. The proposed digital clone modelling framework is validated using the BNZ building and an experimental RC test structure damaged severely due to three successive shake-table excitations. In both structures, structural damage intensifies the pinching effects in hysteresis responses. Results show the basis functions identified from the HLA-SHM results for both structures under Event 1 can online estimate structural damage due to subsequent Events 2-3 from the measured structural responses, making them valuable tool for rapid warning systems. Moreover, the digital twins derived for these two structures under Event 1 can successfully predict structural responses and damage under Events 2-3, which can be integrated with the incremental dynamic analysis (IDA) method to assess structural collapse and its financial risks. Furthermore, it enables multi-step IDA to evaluate earthquake series' impacts on structures. Overall, this thesis develops an efficient method for providing reliable information on earthquake-affected structures' current and future status during or immediately after an earthquake, considerably guaranteeing safety. Significant validation is implemented against both experimental and real data of RC structures, which thus clearly indicate the accurate predictive performance of this HLA-based method.
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’.
