Research in the governance of urban tourist spaces is characterized by a lack of argumentative inquiry and scant use of critical theory. This is evident, particularly, in the study of tourism and post-disaster urban recovery, with very few contributions assessing the phenomenon from a social theory perspective. This thesis examines the complex phenomenon of planning and governance for urban tourism spaces in contexts facing physical recovery from natural disasters. It does so by looking at the governance dynamics and the mechanism of decision- making put in place before and after triggering events like earthquakes and tsunamis. This thesis provides evidence from Christchurch, New Zealand, by focusing on the policies and strategies for the regeneration of the city centre put in place before and after the disruptive earthquakes of 2010 and 2011. The thesis looks at power relations, structures and ideologies through a Lukesian appraisal of pre-and-post disaster governance from two relevant urban tourist spaces located in the Christchurch central city area: the Arts Centre of Christchurch and the Town Hall and Performing Arts Precinct. The research strategy adopted for the study combined archival research, interviews with key stakeholders and fieldwork notes over a period of two years. The research deployed a comparative case study methodology that focuses on projects taking place within a spatially defined area of the city centre where special legislation was enacted as result of the earthquakes. The findings from the interviews and their triangulation with documents retrieved from national and local authorities suggest that the earthquakes affected the engagement among stakeholders and the mechanisms of decision-making. Also, the findings show patterns of disaster capitalism in post-earthquake governance for urban tourist spaces in the Christchurch CBD, with episodes of exclusion, lobbying and amendment of rules and legislation that directly benefited the interests of a narrow group of privileged stakeholders. Overall, the study shows that the earthquakes of 2010 and 2011 accelerated neoliberal practices of site development in Christchurch, with the seismic events used as a pretext to implement market-oriented site projects in the CBD area.
Reinforced concrete structures designed in pre-1970s are vulnerable under earthquakes due to lack of seismic detailing to provide adequate ductility. Typical deficiencies of pre-1970s reinforced concrete structures are (a) use of plain bars as longitudinal reinforcement, (b) inadequate anchorage of beam longitudinal reinforcement in the column (particularly exterior column), (c) lack of joint transverse reinforcement if any, (d) lapped splices located just above joint, and (e) low concrete strength. Furthermore, the use of infill walls is a controversial issue because it can help to provide additional stiffness to the structure on the positive side and on the negative side it can increase the possibility of soft-storey mechanisms if it is distributed irregularly. Experimental research to investigate the possible seismic behaviour of pre-1970s reinforced concrete structures have been carried out in the past. However, there is still an absence of experimental tests on the 3-D response of existing beam-column joints under bi-directional cyclic loading, such as corner joints. As part of the research work herein presented, a series of experimental tests on beam-column subassemblies with typical detailing of pre-1970s buildings has been carried out to investigate the behaviour of existing reinforced concrete structures. Six two-third scale plane frame exterior beam-column joint subassemblies were constructed and tested under quasi-static cyclic loading in the Structural Laboratory of the University of Canterbury. The reinforcement detailing and beam dimension were varied to investigate their effect on the seismic behaviour. Four specimens were conventional deep beam-column joint, with two of them using deformed longitudinal bars and beam bars bent in to the joint and the two others using plain round longitudinal bars and beam bars with end hooks. The other two specimens were shallow beam-column joint, one with deformed longitudinal bars and beam bars bent in to the joint, the other with plain round longitudinal bars and beam bars with end hooks. All units had one transverse reinforcement in the joint. The results of the experimental tests indicated that conventional exterior beam-column joint with typical detailing of pre-1970s building would experience serious diagonal tension cracking in the joint panel under earthquake. The use of plain round bars with end hooks for beam longitudinal reinforcement results in more severe damage in the joint core when compared to the use of deformed bars for beam longitudinal reinforcement bent in to the joint, due to the combination of bar slips and concrete crushing. One interesting outcome is that the use of shallow beam in the exterior beam-column joint could avoid the joint cracking due to the beam size although the strength provided lower when compared with the use of deep beam with equal moment capacity. Therefore, taking into account the low strength and stiffness, shallow beam can be reintroduced as an alternative solution in design process. In addition, the presence of single transverse reinforcement in the joint core can provide additional confinement after the first crack occurred, thus delaying the strength degradation of the structure. Three two-third scale space frame corner beam-column joint subassemblies were also constructed to investigate the biaxial loading effect. Two specimens were deep-deep beam-corner column joint specimens and the other one was deep-shallow beam-corner column joint specimen. One deep-deep beam-corner column joint specimen was not using any transverse reinforcement in the joint core while the two other specimens were using one transverse reinforcement in the joint core. Plain round longitudinal bars were used for all units with hook anchorage for the beam bars. Results from the tests confirmed the evidences from earthquake damage observations with the exterior 3-D (corner) beam-column joint subjected to biaxial loading would have less strength and suffer higher damage in the joint area under earthquake. Furthermore, the joint shear relation in the two directions is calibrated from the results to provide better analysis. An analytical model was used to simulate the seismic behaviour of the joints with the help of Ruaumoko software. Alternative strength degradation curves corresponding to different reinforcement detailing of beam-column joint unit were proposed based on the test results.
Natural hazard disasters often have large area-wide impacts, which can cause adverse stress-related mental health outcomes in exposed populations. As a result, increased treatment-seeking may be observed, which puts a strain on the limited public health care resources particularly in the aftermath of a disaster. It is therefore important for public health care planners to know whom to target, but also where and when to initiate intervention programs that promote emotional wellbeing and prevent the development of mental disorders after catastrophic events. A large body of literature assesses factors that predict and mitigate disaster-related mental disorders at various time periods, but the spatial component has rarely been investigated in disaster mental health research. This thesis uses spatial and spatio-temporal analysis techniques to examine when and where higher and lower than expected mood and anxiety symptom treatments occurred in the severely affected Christchurch urban area (New Zealand) after the 2010/11 Canterbury earthquakes. High-risk groups are identified and a possible relationship between exposure to the earthquakes and their physical impacts and mood and anxiety symptom treatments is assessed. The main research aim is to test the hypothesis that more severely affected Christchurch residents were more likely to show mood and anxiety symptoms when seeking treatment than less affected ones, in essence, testing for a dose-response relationship. The data consisted of mood and anxiety symptom treatment information from the New Zealand Ministry of Health’s administrative databases and demographic information from the National Health Index (NHI) register, when combined built a unique and rich source for identifying publically funded stress-related treatments for mood and anxiety symptoms in almost the whole population of the study area. The Christchurch urban area within the Christchurch City Council (CCC) boundary was the area of interest in which spatial variations in these treatments were assessed. Spatial and spatio-temporal analyses were done by applying retrospective space-time and spatial variation in temporal trends analysis using SaTScan™ software, and Bayesian hierarchical modelling techniques for disease mapping using WinBUGS software. The thesis identified an overall earthquake-exposure effect on mood and anxiety symptom treatments among Christchurch residents in the context of the earthquakes as they experienced stronger increases in the risk of being treated especially shortly after the catastrophic 2011 Christchurch earthquake compared to the rest of New Zealand. High-risk groups included females, elderly, children and those with a pre-existing mental illness with elderly and children especially at-risk in the context of the earthquakes. Looking at the spatio-temporal distribution of mood and anxiety symptom treatments in the Christchurch urban area, a high rates cluster ranging from the severely affected central city to the southeast was found post-disaster. Analysing residential exposure to various earthquake impacts found that living in closer proximity to more affected areas was identified as a risk factor for mood and anxiety symptom treatments, which largely confirms a dose-response relationship between level of affectedness and mood and anxiety symptom treatments. However, little changes in the spatial distribution of mood and anxiety symptom treatments occurred in the Christchurch urban area over time indicating that these results may have been biased by pre-existing spatial disparities. Additionally, the post-disaster mobility activity from severely affected eastern to the generally less affected western and northern parts of the city seemed to have played an important role as the strongest increases in treatment rates occurred in less affected northern areas of the city, whereas the severely affected eastern areas tended to show the lowest increases. An investigation into the different effects of mobility confirmed that within-city movers and temporary relocatees were generally more likely to receive care or treatment for mood or anxiety symptoms, but moving within the city was identified as a protective factor over time. In contrast, moving out of the city from minor, moderately or severely damaged plain areas of the city, which are generally less affluent than Port Hills areas, was identified as a risk factor in the second year post-disaster. Moreover, residents from less damaged plain areas of the city showed a decrease in the likelihood of receiving care or treatment for mood or anxiety symptoms compared to those from undamaged plain areas over time, which also contradicts a possible dose-response relationship. Finally, the effects of the social and physical environment, as well as community resilience on mood and anxiety symptom treatments among long-term stayers from Christchurch communities indicate an exacerbation of pre-existing mood and anxiety symptom treatment disparities in the city, whereas exposure to ‘felt’ earthquake intensities did not show a statistically significant effect. The findings of this thesis highlight the complex relationship between different levels of exposure to a severe natural disaster and adverse mental health outcomes in a severely affected region. It is one of the few studies that have access to area-wide health and impact information, are able to do a pre-disaster / post-disaster comparison and track their sample population to apply spatial and spatio-temporal analysis techniques for exposure assessment. Thus, this thesis enhances knowledge about the spatio-temporal distribution of adverse mental health outcomes in the context of a severe natural disaster and informs public health care planners, not only about high-risk groups, but also where and when to target health interventions. The results indicate that such programs should broadly target residents living in more affected areas as they are likely to face daily hardship by living in a disrupted environment and may have already been the most vulnerable ones before the disaster. Special attention should be focussed on women, elderly, children and people with pre-existing mental illnesses as they are most likely to receive care or treatment for stress-related mental health symptoms. Moreover, permanent relocatees from affected areas and temporarily relocatees shortly after the disaster may need special attention as they face additional stressors due to the relocation that may lead to the development of adverse mental health outcomes needing treatment.
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.
In order to provide information related to seismic vulnerability of non-ductile reinforced concrete (RC) frame buildings, and as a complementary investigation on innovative feasible retrofit solutions developed in the past six years at the University of Canterbury on pre-19170 reinforced concrete buildings, a frame building representative of older construction practice was tested on the shake table. The specimen, 1/2.5 scale, consists of two 3-storey 2-bay asymmetric frames in parallel, one interior and one exterior, jointed together by transverse beams and floor slabs. The as-built (benchmark) specimen was first tested under increasing ground motion amplitudes using records from Loma Prieta Earthquake (California, 1989) and suffered significant damage at the upper floor, most of it due to lap splices failure. As a consequence, in a second stage, the specimen was repaired and modified by removing the concrete in the lap splice region, welding the column longitudinal bars, replacing the removed concrete with structural mortar, and injecting cracks with epoxy resin. The modified as-built specimen was then tested using data recorded during Darfield (New Zealand, 2010) and Maule (Chile, 2010) Earthquakes, with whom the specimen showed remarkably different responses attributed to the main variation in frequency content and duration. In this contribution, the seismic performance of the three series of experiments are presented and compared.
The November 2016 MW 7.8 Kaikōura Earthquake initiated beneath the North Culverden basin on The Humps fault and propagated north-eastwards, rupturing at least 17 faults along a cumulative length of ~180 km. The geomorphic expression of The Humps Fault across the Emu Plains, along the NW margin of Culverden basin, comprises a series of near-parallel strands separated by up to 3 km across strike. The various strands strike east to east-northeast and have been projected to mainly dip steeply to the south in seismic data (~80°). In this area, the fault predominantly accommodates right-lateral slip, with uplift and subsidence confined to releasing and restraining bends and step-overs at a range of scales. The Kaikōura event ruptured pre-existing fault scarps along the Emu Plains, which had been partly identified prior to the earthquake. Geomorphology and faulting expression of The Humps Fault on The Emu Plains was mapped, along with faulting related structures which did not rupture in the 2016 earthquake. Fault ruptures strands are combined into sections and the kinematic deformation of sections analysed to provide a moment tensor fault plane solution. This fault plane solution is consistent with the regional principal horizontal shortening direction (PHS) of ~115°, similar to seismic focal mechanism solutions of some of the nearby aftershocks of the Kaikōura earthquake, and similar to the adjacent Hope Fault. To constrain the timing of paleoseismic events, a trench was excavated across the fault where it crossed a late Quaternary alluvial fan. Mapping of stratigraphy exposed in the trench walls, and dating of variably deformed strata, constrains the pre-historic earthquake event history at the trench site. The available data provides evidence for at least three paleo-earthquakes within the last 15.1 ka, with a possible fourth (penultimate) event. These events are estimated to have occurred at 7.7-10.3 ka, 10.3-14.8 ka, and one or more events that are older than ~15.1 ka. Some evidence suggests an additional penultimate event between 1850 C.E and 7.7 ka. Time-integrated slip-rates at three locations on the fault are measured using paleo-channels as piercing points. These sites give horizontal slip rates of 0.57 ± 0.1 mm/year, 0.49 ± 0.1 mm/year and one site constrains a minimum of between 0.1 - 0.4 mm/year. Two vertical slip-rates are calculated to be constrained to a maximum of 0.2 ± 0.02 mm/year at one site and between 0.02 and 0.1 mm/year at another site. Prior to this study, The Humps fault had only been partially documented in reconnaissance level mapping in the district, and no previous paleoseismic or slip rate data had been reported. This project has provided a detailed fault zone tectonic geomorphic map and established new slip-rate and paleoseismic data. The results highlight that The Humps fault plays an important role in regional seismicity and in accommodating plate boundary deformation across the North Canterbury region.
This thesis documents the development and demonstration of an assessment method for analysing earthquake-related damage to concrete waste water gravity pipes in Christchurch, New Zealand, following the 2010-2011 Canterbury Earthquake Sequence (CES). The method is intended to be internationally adaptable to assist territorial local authorities with improving lifelines infrastructure disaster impact assessment and improvements in resilience. This is achieved through the provision of high-resolution, localised damage data, which demonstrate earthquake impacts along the pipe length. The insights gained will assist decision making and the prioritisation of resources following earthquake events to quickly and efficiently restore network function and reduce community impacts. The method involved obtaining a selection of 55 reinforced concrete gravity waste water pipes with available Closed-Circuit Television (CCTV) inspection footage filmed before and after the CES. The pipes were assessed by reviewing the recordings, and damage was mapped to the nearest metre along the pipe length using Geographic Information Systems. An established, systematic coding process was used for reporting the nature and severity of the observed damage, and to differentiate between pre-existing and new damage resulting from the CES. The damage items were overlaid with geospatial data such as Light Detection and Ranging (LiDAR)-derived ground deformation data, Liquefaction Resistance Index data and seismic ground motion data (Peak Ground acceleration and Peak Ground Velocity) to identify potential relationships between these parameters and pipe performance. Initial assessment outcomes for the pipe selection revealed that main pipe joints and lateral connections were more vulnerable than the pipe body during a seismic event. Smaller diameter pipes may also be more vulnerable than larger pipes during a seismic event. Obvious differential ground movement resulted in increased local damage observations in many cases, however this was not obvious for all pipes. Pipes with older installation ages exhibited more overall damage prior to a seismic event, which is likely attributable to increased chemical and biological deterioration. However, no evidence was found relating pipe age to performance during a seismic event. No evidence was found linking levels of pre-CES damage in a pipe with subsequent seismic performance, and seismic performance with liquefaction resistance or magnitude of seismic ground motion. The results reported are of limited application due to the small demonstration sample size, but reveal the additional level of detail and insight possible using the method presented in this thesis over existing assessment methods, especially in relation to high resolution variations along the length of the pipe such as localised ground deformations evidenced by LiDAR. The results may be improved by studying a larger and more diverse sample pool, automating data collection and input processes in order to improve efficiency and consider additional input such as pipe dip and cumulative damage over a large distance. The method is dependent on comprehensive and accurate pre-event CCTV assessments and LIDAR data so that post-event data could be compared. It is proposed that local territorial authorities should prioritise acquiring this information as a first important step towards improving the seismic resilience of a gravity waste water pipe network.
This thesis documents the development and demonstration of an assessment method for analysing earthquake-related damage to concrete waste water gravity pipes in Christchurch, New Zealand, following the 2010-2011 Canterbury Earthquake Sequence (CES). The method is intended to be internationally adaptable to assist territorial local authorities with improving lifelines infrastructure disaster impact assessment and improvements in resilience. This is achieved through the provision of high-resolution, localised damage data, which demonstrate earthquake impacts along the pipe length. The insights gained will assist decision making and the prioritisation of resources following earthquake events to quickly and efficiently restore network function and reduce community impacts. The method involved obtaining a selection of 55 reinforced concrete gravity waste water pipes with available Closed-Circuit Television (CCTV) inspection footage filmed before and after the CES. The pipes were assessed by reviewing the recordings, and damage was mapped to the nearest metre along the pipe length using Geographic Information Systems. An established, systematic coding process was used for reporting the nature and severity of the observed damage, and to differentiate between pre-existing and new damage resulting from the CES. The damage items were overlaid with geospatial data such as Light Detection and Ranging (LiDAR)-derived ground deformation data, Liquefaction Resistance Index data and seismic ground motion data (Peak Ground acceleration and Peak Ground Velocity) to identify potential relationships between these parameters and pipe performance. Initial assessment outcomes for the pipe selection revealed that main pipe joints and lateral connections were more vulnerable than the pipe body during a seismic event. Smaller diameter pipes may also be more vulnerable than larger pipes during a seismic event. Obvious differential ground movement resulted in increased local damage observations in many cases, however this was not obvious for all pipes. Pipes with older installation ages exhibited more overall damage prior to a seismic event, which is likely attributable to increased chemical and biological deterioration. However, no evidence was found relating pipe age to performance during a seismic event. No evidence was found linking levels of pre-CES damage in a pipe with subsequent seismic performance, and seismic performance with liquefaction resistance or magnitude of seismic ground motion. The results reported are of limited application due to the small demonstration sample size, but reveal the additional level of detail and insight possible using the method presented in this thesis over existing assessment methods, especially in relation to high resolution variations along the length of the pipe such as localised ground deformations evidenced by LiDAR. The results may be improved by studying a larger and more diverse sample pool, automating data collection and input processes in order to improve efficiency and consider additional input such as pipe dip and cumulative damage over a large distance. The method is dependent on comprehensive and accurate pre-event CCTV assessments and LIDAR data so that post-event data could be compared. It is proposed that local territorial authorities should prioritise acquiring this information as a first important step towards improving the seismic resilience of a gravity waste water pipe network.
The development of cheap, whilst effective and relatively non-invasive structural retrofit techniques for existing non-ductile reinforced concrete (RC) structures still remains the most challenging issue for a wide implementation on a macro scale. Seismic retrofit is too often being confused as purely structural strengthening. As part of a six-years national project on “Seismic retrofit solutions for NZ multi-storey building”, focus has been given at the University of Canterbury on the development of a counter-intuitive retrofit strategy for earthquake vulnerable existing rc frame, based on a “selective weakening” (SW) approach. After an overview of the SW concept, this paper presents the experimental and numerical validation of a SW retrofit strategy for earthquake vulnerable existing RC frame with particular focus on the exterior beam-column (b-c) joints. The exterior b-c joint is a critically vulnerable region in many existing pre-1970s RC frames. By selectively weakening the beam by cutting the bottom longitudinal reinforcements and/or adding external pre-stressing to the b-c joint, a more desirable inelastic mechanism can be attained, leading to improved global seismic performance. The so-called SW retrofit is implemented on four 2/3-scaled exterior RC b-c joint subassemblies, tested under quasi-static cyclic loading at the University of Canterbury. Complemented by refined 3D Finite Element (FE) models and dynamic time-history analyses results, the experimental results have shown the potential of a simple and cost-effective yet structurally efficient structural rehabilitation technique. The research also demonstrated the potential of advanced 3D fracture-mechanics-based microplane concrete modelling for refined FE analysis of non-ductile RC b-c joints.
The structure and geomorphology of active orogens evolves on time scales ranging from a single earthquake to millions of years of tectonic deformation. Analysis of crustal deformation using new and established remote sensing techniques, and integration of these data with field mapping, geochronology and the sedimentary record, create new opportunities to understand orogenic evolution over these timescales. Timor Leste (East Timor) lies on the northern collisional boundary between continental crust from the Australian Plate and the Banda volcanic arc. GPS studies have indicated that the island of Timor is actively shortening. Field mapping and fault kinematic analysis of an emergent Pliocene marine sequence identifies gentle folding, overprinted by a predominance of NW-SE oriented dextral-normal faults and NE-SW oriented sinistral-normal faults that collectively bound large (5-20km2) bedrock massifs throughout the island. These fault systems intersect at non-Andersonian conjugate angles of approximately 120° and accommodate an estimated 20 km of orogen-parallel extension. Folding of Pliocene rocks in Timor may represent an early episode of contraction but the overall pattern of deformation is one of lateral crustal extrusion sub-parallel to the Banda Arc. Stratigraphic relationships suggest that extrusion began prior to 5.5 Ma, during and after initial uplift of the orogen. Sedimentological, geochemical and Nd isotope data indicate that the island of Timor was emergent and shedding terrigenous sediment into carbonate basins prior to 4.5 Ma. Synorogenic tectonic and sedimentary phases initiated almost synchronously across much of Timor Leste and <2 Myr before similar events in West Timor. An increase in plate coupling along this obliquely converging boundary, due to subduction of an outlying continental plateau at the Banda Trench, is proposed as a mechanism for uplift that accounts for orogen-parallel extension and early uplift of Timor Leste. Rapid bathymetric changes around Timor are likely to have played an important role in evolution of the Indonesian Seaway. The 2010 Mw 7.1 Darfield (Canterbury) earthquake in New Zealand was complex, involving multiple faults with strike-slip, reverse and normal displacements. Multi-temporal cadastral surveying and airborne light detection and ranging (LiDAR) surveys allowed surface deformation at the junction of three faults to be analyzed in this study in unprecedented detail. A nested, localized restraining stepover with contractional bulging was identified in an area with the overall fault structure of a releasing bend, highlighting the surface complexities that may develop in fault interaction zones during a single earthquake sequence. The earthquake also caused river avulsion and flooding in this area. Geomorphic investigations of these rivers prior to the earthquake identify plausible precursory patterns, including channel migration and narrowing. Comparison of the pre and post-earthquake geomorphology of the fault rupture also suggests that a subtle scarp or groove was present along much of the trace prior to the Darfield earthquake. Hydrogeology and well logs support a hypothesis of extended slip history and suggests that that the Selwyn River fan may be infilling a graben that has accumulated late Quaternary vertical slip of <30 m. Investigating fault behavior, geomorphic and sedimentary responses over a multitude of time-scales and at different study sites provides insights into fault interactions and orogenesis during single earthquakes and over millions of years of plate boundary deformation.
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.
After a disaster, cities experience profound social and environmental upheaval. Current research on disasters describes this social disruption along with collective community action to provide support. Pre-existing social capital is recognised as fundamental to this observed support. This research examines the relationship between sense of place for neighbourhood, social connectedness and resilience. Canterbury residents experienced considerable and continued disruption following a large and protracted sequence of earthquakes starting in September 2010. A major aftershock on 22 February 2011 caused significant loss of life, destruction of buildings and infrastructure. Following this earthquake some suburbs of Christchurch showed strong collective action. This research examines the features of the built environment that helped to form this cooperative support. Data were collected through semi-structured interviews with 20 key informants followed by 38 participants from four case study suburbs. The objectives were to describe the community response of suburbs, to identify the key features of the built environment and the role of social infrastructure in fostering social connectedness. The last objective was to contribute to future planning for community resilience. The findings from this research indicated that social capital and community competence are significant resources to be called upon after a disaster. Features of the local environment facilitated the formation of neighbourhood connections that enabled participants to cope, manage and to collectively solve problems. These features also strengthened a sense of belonging and attachment to the home territory. Propinquity was important; the bumping and gathering places such as schools, small local shops and parks provided the common ground for meaningful pre-existing local interaction. Well-defined geography, intimate street typology, access to quality natural space and social infrastructure helped to build the local social connections and develop a sense of place. Resourceful individuals and groups were also a factor, and many are drawn to live near the inner city or more natural places. The features are the same well understood attributes that contribute to health and wellbeing. The policy and planning framework needs to consider broader social outcomes, including resilience in new and existing urban developments. The socio-political structures that provide access to secure and stable housing and local education should also be recognised and incorporated into local planning for resilience and the everyday.
Previous research has found that the capacity to self-regulate is associated with a number of positive life outcomes and deficits in self-regulation have been linked with poorer life outcomes. Therefore, parent and child self-regulation is an important focus of the Positive Parenting Program for Teenagers (Teen Triple P). The aim of this study was to investigate if Group Teen Triple P was effective in promoting parental self-regulation and adolescent behaviour change in families affected by the earthquakes in Canterbury NZ between 2010 and 2012. METHOD: Five families with teenagers aged 12-16 years were recruited from among families participating in a Group Teen Triple P program specifically implemented by the education authorities for parents self-reporting long-term negative effects of the earthquakes on their family. A single-case multiple-baseline across participants design was used to examine change in target teenager behaviour. Measures of self-regulation skill acquisition were taken using a coding scheme devised for the study from transcripts of three telephone consultations and from three family discussions at pre-intervention, mid-intervention, and post-intervention. Parents and their child also completed questionnaires addressing adolescent functioning, the parent-adolescent relationship and parenting at pre- and post-intervention. RESULTS: The multiple-baseline data showed that parents were successful at changing targeted behaviour for their child. Analysis of the telephone consultations and family discussions showed that parents increased their self-regulation skills over the therapy period and there was positive change in adolescent behavior reported on the Strengths and Difficulties Questionnaire. Additionally, the results suggested that higher rates and levels of self-regulation in the parents were associated with greater improvements in adolescent behaviour. CONCLUSION: This study demonstrated that the Group Teen Triple P -Program was effective in promoting self-regulation in parents and behaviour change in adolescents, specifically in a post-disaster context.
The Canterbury region of New Zealand experienced a sequence of strong earthquakes during 2010-2011. Responses included government acquisition of many thousands of residential properties in the city of Christchurch in areas with severe earthquake effects. A large and contiguous tract of this ‘red zoned’ land lies in close proximity to the Ōtākaro / Avon River and is known as the Avon-Ōtākaro Red Zone (AORZ). The focus of this study was to provide an overview of the floodplain characteristics of the AORZ and review of international experience in ecological restoration of similar river margin and floodplain ecosystems to extract restoration principles and associated learnings. Compared to pre-earthquake ground levels, the dominant trend in the AORZ is subsidence, together with lateral movement especially in the vicinity of waterway. An important consequence of land subsidence in the lower Ōtākaro / Avon River is greater exposure to flooding and the effects of sea level rise. Scenario modelling for sea level rise indicates that much of the AORZ is exposed to inundation within a 100 year planning horizon based on a 1 m sea level rise. As with decisions on built infrastructure, investments in nature-based ‘green infrastructure’ also require a sound business case including attention to risks posed by climate change. Future-proofing of the expected benefits of ecological restoration must therefore be secured by design. Understanding and managing the hydrology and floodplain dynamics are vital to the future of the AORZ. However, these characteristics are shared by other floodplain and river restoration projects worldwide. Identifying successful approaches provides a useful a source of useful information for floodplain planning in the AORZ. This report presents results from a comparative case study of three international examples to identify relevant principles for large-scale floodplain management at coastal lowland sites.
Environmental stress and disturbance can affect the structure and functioning of marine ecosystems by altering their physical, chemical and biological features. In estuaries, benthic invertebrate communities play important roles in structuring sediments, influencing primary production and biogeochemical flux, and occupying key food web positions. Stress and disturbance can reduce species diversity, richness and abundance, with ecological theory predicting that biodiversity will be at its lowest soon after a disturbance with assemblages dominated by opportunistic species. The Avon-Heathcote Estuary in Christchurch New Zealand has provided a novel opportunity to examine the effects of stress, in the form of eutrophication, and disturbance, in the form of cataclysmic earthquake events, on the structure and functioning of an estuarine ecosystem. For more than 50 years, large quantities (up to 500,000m3/day) of treated wastewater were released into this estuary but in March 2010 this was diverted to an ocean outfall, thereby reducing the nutrient loading by around 90% to the estuary. This study was therefore initially focussed on the reversal of eutrophication and consequent effects on food web structure in the estuary as it responded to lower nutrients. In 2011, however, Christchurch was struck with a series of large earthquakes that greatly changed the estuary. Massive amounts of liquefied sediments, covering up to 65% of the estuary floor, were forced up from deep below the estuary, the estuary was tilted by up to a 50cm rise on one side and a corresponding drop on the other, and large quantities of raw sewage from broken wastewater infrastructure entered the estuary for up to nine months. This study was therefore a test of the potentially synergistic effects of nutrient reduction and earthquake disturbance on invertebrate communities, associated habitats and food web dynamics. Because there was considerable site-to-site heterogeneity in the estuary, the sites in this study were selected to represent a eutrophication gradient from relatively “clean” (where the influence of tidal flows was high) to highly impacted (near the historical discharge site). The study was structured around these sites, with components before the wastewater diversion, after the diversion but before the earthquakes, and after the earthquakes. The eutrophication gradient was reflected in the composition and isotopic chemistry of primary producer and invertebrate communities and the characteristics of sediments across the sample sites. Sites closest to the former wastewater discharge pipe were the most eutrophic and had cohesive organic -rich, fine sediments and relatively depauperate communities dominated by the opportunistic taxa Capitellidae. The less-impacted sites had coarser, sandier sediments with fewer pollutants and far less organic matter than at the eutrophic sites, relatively high diversity and lower abundances of micro- and macro-algae. Sewage-derived nitrogen had became incorporated into the estuarine food web at the eutrophic sites, starting at the base of the food chain with benthic microalgae (BMA), which were found to use mostly sediment-derived nitrogen. Stable isotopic analysis showed that δ13C and δ15N values of most food sources and consumers varied spatially, temporally and in relation to the diversion of wastewater, whereas the earthquakes did not appear to affect the overall estuarine food web structure. This was seen particularly at the most eutrophic site, where isotopic signatures became more similar to the cleaner sites over two-and-a-half years after the diversion. New sediments (liquefaction) produced by the earthquakes were found to be coarser, have lower concentrations of heavy metals and less organic matter than old (existing) sediments. They also had fewer macroinvertebrate inhabitants initially after the earthquakes but most areas recovered to pre-earthquake abundance and diversity within two years. Field experiments showed that there were higher amounts of primary production and lower amounts of nutrient efflux from new sediments at the eutrophic sites after the earthquakes. Primary production was highest in new sediments due to the increased photosynthetic efficiency of BMA resulting from the increased permeability of new sediments allowing increased light penetration, enhanced vertical migration of BMA and the enhanced transport of oxygen and nutrients. The reduced efflux of NH4-N in new sediments indicated that the capping of a large portion of eutrophic old sediments with new sediments had reduced the release of legacy nutrients (originating from the historical discharge) from the sediments to the overlying water. Laboratory experiments using an array of species and old and new sediments showed that invertebrates altered levels of primary production and nutrient flux but effects varied among species. The mud snail Amphibola crenata and mud crab Austrohelice crassa were found to reduce primary production and BMA biomass through the consumption of BMA (both species) and its burial from bioturbation and the construction of burrows (Austrohelice). In contrast, the cockle Austrovenus stutchburyi did not significantly affect primary production and BMA biomass. These results show that changes in the structure of invertebrate communities resulting from disturbances can also have consequences for the functioning of the system. The major conclusions of this study were that the wastewater diversion had a major effect on food web dynamics and that the large quantities of clean and unpolluted new sediments introduced to the estuary during the earthquakes altered the recovery trajectory of the estuary, accelerating it at least throughout the duration of this study. This was largely through the ‘capping’ effect of the new liquefied, coarser-grained sediments as they dissipated across the estuary and covered much of the old organic-rich eutrophic sediments. For all aspects of this study, the largest changes occurred at the most eutrophic sites; however, the surrounding habitats were important as they provided the context for recovery of the estuary, particularly because of the very strong influence of sediments, their biogeochemistry, microalgal and macroalgal dynamics. There have been few studies documenting system level responses to eutrophication amelioration and to the best on my knowledge there are no other published studies examining the impacts of large earthquakes on benthic communities in an estuarine ecosystem. This research gives valuable insight and advancements in the scientific understanding of the effects that eutrophication recovery and large-scale disturbances can have on the ecology of a soft-sediment ecosystem.
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 University of Canterbury Dept. of Chemistry has weathered the Canterbury Earthquake of September 4, 2010 very well due to a combination of good luck, good planning and dedicated effort. We owe a great deal to university Emergency Response Team and Facilities Management Personnel. The overall emergency preparedness of the university was tested to a degree far beyond anything else in its history and shown to be well up to scratch. A strong cooperative relationship between the pan-campus controlling body and the departmental response teams greatly facilitated our efforts. Information and assistance was provided promptly, as and when we needed it without unnecessary bureaucratic overheads. At the departmental level we are indebted to the technical staff who implemented the invaluable pre-quake mitigation measures and carried the majority of the post-quake clean-up workload. These people put aside their personal concerns and anxieties at a time when magnitude-5 aftershocks were still a regular occurrence.
A seismic financial risk analysis of typical New Zealand reinforced concrete buildings constructed with topped precast concrete hollow-core units is performed on the basis of experimental research undertaken at the University of Canterbury over the last five years. An extensive study that examines seismic demands on a variety of multi-storey RC buildings is described and supplemented by the experimental results to determine the inter-storey drift capacities of the buildings. Results of a full-scale precast concrete super-assemblage constructed and tested in the laboratory in two stages are used. The first stage investigates existing construction and demonstrates major shortcomings in construction practice that would lead to very poor seismic performance. The second stage examines the performance of the details provided by Amendment No. 3 to the New Zealand Concrete Design Code NZS 3101:1995. This paper uses a probabilistic financial risk assessment framework to estimate the expected annual loss (EAL) from previously developed fragility curves of RC buildings with precast hollow core floors connected to the frames according to the pre-2004 standard and the two connection details recommended in the 2004 amendment. Risks posed by different levels of damage and by earthquakes of different frequencies are examined. The structural performance and financial implications of the three different connection details are compared. The study shows that the improved connection details recommended in the 2004 amendment give a significant economic payback in terms of drastically reduced financial risk, which is also representative of smaller maintenance cost and cheaper insurance premiums.
The self-regulation approach to educating parents focusses on promoting parenting confidence, independence, and the ability to solve future problems. As parents learn the skills to modify their own behaviour, in turn, they aim to foster self-regulation in their children/adolescents. A need had been identified by Christchurch school principals for the Ministry of Education to respond to the post-earthquake stress in local families. The aim of this study was to investigate if a parenting programme was effective in promoting parental self-management skills and adolescent behaviour change in Christchurch families affected by earthquakes between 2010 and 2012. A single case research design was used to follow five families with adolescents (12-16 years old) as they participated in a Group Teen Triple P – Positive Parenting Programme. Measures of self-management skill acquisition were taken during three family discussions (pre-intervention, mid-intervention, and post-intervention) and during the three telephone consultations (Sessions 5-7). Adolescent target behaviour tallies were also analysed for change. The main findings showed that parental self-management skill acquisition increased over-time accompanied by positive change in adolescent behaviour. Additionally, the results suggested that higher rates and levels of self-management skill acquisition in the parents were associated with greater improvements in adolescent behaviour. This study demonstrated that Group Teen Triple P – Positive Parenting Programme was effective in promoting self-management competencies in parents and behaviour change in adolescents.
The recent instances of seismic activity in Canterbury (2010/11) and Kaikōura (2016) in New Zealand have exposed an unexpected level of damage to non-structural components, such as buried pipelines and building envelope systems. The cost of broken buried infrastructure, such as pipeline systems, to the Christchurch Council was excessive, as was the cost of repairing building envelopes to building owners in both Christchurch and Wellington (due to the Kaikōura earthquake), which indicates there are problems with compliance pathways for both of these systems. Councils rely on product testing and robust engineering design practices to provide compliance certification on the suitability of product systems, while asset and building owners rely on the compliance as proof of an acceptable design. In addition, forensic engineers and lifeline analysts rely on the same product testing and design techniques to analyse earthquake-related failures or predict future outcomes pre-earthquake, respectively. The aim of this research was to record the actual field-observed damage from the Canterbury and Kaikōura earthquakes of seismic damage to buried pipeline and building envelope systems, develop suitable testing protocols to be able to test the systems’ seismic resilience, and produce prediction design tools that deliver results that reflect the collected field observations with better accuracy than the present tools used by forensic engineers and lifeline analysts. The main research chapters of this thesis comprise of four publications that describe the gathering of seismic damage to pipes (Publication 1 of 4) and building envelopes (Publication 2 of 4). Experimental testing and the development of prediction design tools for both systems are described in Publications 3 and 4. The field observation (discussed in Publication 1 of 4) revealed that segmented pipe joints, such as those used in thick-walled PVC pipes, were particularly unsatisfactory with respect to the joint’s seismic resilience capabilities. Once the joint was damaged, silt and other deleterious material were able to penetrate the pipeline, causing blockages and the shutdown of key infrastructure services. At present, the governing Standards for PVC pipes are AS/NZS 1477 (pressure systems) and AS/NZS 1260 (gravity systems), which do not include a protocol for evaluating the PVC pipes for joint seismic resilience. Testing methodologies were designed to test a PVC pipe joint under various different simultaneously applied axial and transverse loads (discussed in Publication 3 of 4). The goal of the laboratory experiment was to establish an easy to apply testing protocol that could fill the void in the mentioned standards and produce boundary data that could be used to develop a design tool that could predict the observed failures given site-specific conditions surrounding the pipe. A tremendous amount of building envelope glazing system damage was recorded in the CBDs of both Christchurch and Wellington, which included gasket dislodgement, cracked glazing, and dislodged glazing. The observational research (Publication 2 of 4) concluded that the glazing systems were a good indication of building envelope damage as the glazing had consistent breaking characteristics, like a ballistic fuse used in forensic blast analysis. The compliance testing protocol recognised in the New Zealand Building Code, Verification Method E2/VM1, relies on the testing method from the Standard AS/NZS 4284 and stipulates the inclusion of typical penetrations, such as glazing systems, to be included in the test specimen. Some of the building envelope systems that failed in the recent New Zealand earthquakes were assessed with glazing systems using either the AS/NZS 4284 or E2/VM1 methods and still failed unexpectedly, which suggests that improvements to the testing protocols are required. An experiment was designed to mimic the observed earthquake damage using bi-directional loading (discussed in Publication 4 of 4) and to identify improvements to the current testing protocol. In a similar way to pipes, the observational and test data was then used to develop a design prediction tool. For both pipes (Publication 3 of 4) and glazing systems (Publication 4 of 4), experimentation suggests that modifying the existing testing Standards would yield more realistic earthquake damage results. The research indicates that including a specific joint testing regime for pipes and positioning the glazing system in a specific location in the specimen would improve the relevant Standards with respect to seismic resilience of these systems. Improving seismic resilience in pipe joints and glazing systems would improve existing Council compliance pathways, which would potentially reduce the liability of damage claims against the government after an earthquake event. The developed design prediction tool, for both pipe and glazing systems, uses local data specific to the system being scrutinised, such as local geology, dimensional characteristics of the system, actual or predicted peak ground accelerations (both vertically and horizontally) and results of product-specific bi-directional testing. The design prediction tools would improve the accuracy of existing techniques used by forensic engineers examining the cause of failure after an earthquake and for lifeline analysts examining predictive earthquake damage scenarios.
The Canterbury Earthquakes of 2010-2011, in particular the 4th September 2010 Darfield earthquake and the 22nd February 2011 Christchurch earthquake, produced severe and widespread liquefaction in Christchurch and surrounding areas. The scale of the liquefaction was unprecedented, and caused extensive damage to a variety of man-made structures, including residential houses. Around 20,000 residential houses suffered serious damage as a direct result of the effects of liquefaction, and this resulted in approximately 7000 houses in the worst-hit areas being abandoned. Despite the good performance of light timber-framed houses under the inertial loads of the earthquake, these structures could not withstand the large loads and deformations associated with liquefaction, resulting in significant damage. The key structural component of houses subjected to liquefaction effects was found to be their foundations, as these are in direct contact with the ground. The performance of house foundations directly influenced the performance of the structure as a whole. Because of this, and due to the lack of research in this area, it was decided to investigate the performance of houses and in particular their foundations when subjected to the effects of liquefaction. The data from the inspections of approximately 500 houses conducted by a University of Canterbury summer research team following the 4th September 2010 earthquake in the worst-hit areas of Christchurch were analysed to determine the general performance of residential houses when subjected to high liquefaction loads. This was followed by the detailed inspection of around 170 houses with four different foundation types common to Christchurch and New Zealand: Concrete perimeter with short piers constructed to NZS3604, concrete slab-on-grade also to NZS3604, RibRaft slabs designed by Firth Industries and driven pile foundations. With a focus on foundations, floor levels and slopes were measured, and the damage to all areas of the house and property were recorded. Seven invasive inspections were also conducted on houses being demolished, to examine in more detail the deformation modes and the causes of damage in severely affected houses. The simplified modelling of concrete perimeter sections subjected to a variety of liquefaction-related scenarios was also performed, to examine the comparative performance of foundations built in different periods, and the loads generated under various bearing loss and lateral spreading cases. It was found that the level of foundation damage is directly related to the level of liquefaction experienced, and that foundation damage and liquefaction severity in turn influence the performance of the superstructure. Concrete perimeter foundations were found to have performed most poorly, suffering high local floor slopes and being likely to require foundation repairs even when liquefaction was low enough that no surface ejecta was seen. This was due to their weak, flexible foundation structure, which cannot withstand liquefaction loads without deforming. The vulnerability of concrete perimeter foundations was confirmed through modelling. Slab-on-grade foundations performed better, and were unlikely to require repairs at low levels of liquefaction. Ribraft and piled foundations performed the best, with repairs unlikely up to moderate levels of liquefaction. However, all foundation types were susceptible to significant damage at higher levels of liquefaction, with maximum differential settlements of 474mm, 202mm, 182mm and 250mm found for concrete perimeter, slab-on-grade, ribraft and piled foundations respectively when subjected to significant lateral spreading, the most severe loading scenario caused by liquefaction. It was found through the analysis of the data that the type of exterior wall cladding, either heavy or light, and the number of storeys, did not affect the performance of foundations. This was also shown through modelling for concrete perimeter foundations, and is due to the increased foundation strengths provided for heavily cladded and two-storey houses. Heavy roof claddings were found to increase the demands on foundations, worsening their performance. Pre-1930 concrete perimeter foundations were also found to be very vulnerable to damage under liquefaction loads, due to their weak and brittle construction.
The supply of water following disasters has always been of significant concern to communities. Failure of water systems not only causes difficulties for residents and critical users but may also affect other hard and soft infrastructure and services. The dependency of communities and other infrastructure on the availability of safe and reliable water places even more emphasis on the resilience of water supply systems. This thesis makes two major contributions. First, it proposes a framework for measuring the multifaceted resilience of water systems, focusing on the significance of the characteristics of different communities for the resilience of water supply systems. The proposed framework, known as the CARE framework, consists of eight principal activities: (1) developing a conceptual framework; (2) selecting appropriate indicators; (3) refining the indicators based on data availability; (4) correlation analysis; (5) scaling the indicators; (6) weighting the variables; (7) measuring the indicators; and (8) aggregating the indicators. This framework allows researchers to develop appropriate indicators in each dimension of resilience (i.e., technical, organisational, social, and economic), and enables decision makers to more easily participate in the process and follow the procedure for composite indicator development. Second, it identifies the significant technical, social, organisational and economic factors, and the relevant indicators for measuring these factors. The factors and indicators were gathered through a comprehensive literature review. They were then verified and ranked through a series of interviews with water supply and resilience specialists, social scientists and economists. Vulnerability, redundancy and criticality were identified as the most significant technical factors affecting water supply system robustness, and consequently resilience. These factors were tested for a scenario earthquake of Mw 7.6 in Pukerua Bay in New Zealand. Four social factors and seven indicators were identified in this study. The social factors are individual demands and capacities, individual involvement in the community, violence level in the community, and trust. The indicators are the Giving Index, homicide rate, assault rate, inverse trust in army, inverse trust in police, mean years of school, and perception of crime. These indicators were tested in Chile and New Zealand, which experienced earthquakes in 2010 and 2011 respectively. The social factors were also tested in Vanuatu following TC Pam, which hit the country in March 2015. Interestingly, the organisational dimension contributed the largest number of factors and indicators for measuring water supply resilience to disasters. The study identified six organisational factors and 17 indicators that can affect water supply resilience to disasters. The factors are: disaster precaution; predisaster planning; data availability, data accessibility and information sharing; staff, parts, and equipment availability; pre-disaster maintenance; and governance. The identified factors and their indicators were tested for the case of Christchurch, New Zealand, to understand how organisational capacity affected water supply resilience following the earthquake in February 2011. Governance and availability of critical staff following the earthquake were the strongest organisational factors for the Christchurch City Council, while the lack of early warning systems and emergency response planning were identified as areas that needed to be addressed. Economic capacity and quick access to finance were found to be the main economic factors influencing the resilience of water systems. Quick access to finance is most important in the early stages following a disaster for response and restoration, but its importance declines over time. In contrast, the economic capacity of the disaster struck area and the water sector play a vital role in the subsequent reconstruction phase rather than in the response and restoration period. Indicators for these factors were tested for the case of the February 2011 earthquake in Christchurch, New Zealand. Finally, a new approach to measuring water supply resilience is proposed. This approach measures the resilience of the water supply system based on actual water demand following an earthquake. The demand-based method calculates resilience based on the difference between water demand and system capacity by measuring actual water shortage (i.e., the difference between water availability and demand) following an earthquake.
Christchurch Ōtautahi, New Zealand, is a city of myriad waterways and springs. Māori, the indigenous people of New Zealand, have water quality at the core of their cultural values. The city’s rivers include the Avon/Ōtākaro, central to the city centre’s aesthetic appeal since early settlement, and the Heathcote/Ōpāwaho. Both have been degraded with increasing urbanisation. The destructive earthquake sequence that occurred during 2010/11 presented an opportunity to rebuild significant areas of the city. Public consultation identified enthusiasm to rebuild a sustainable city. A sustainable water sensitive city is one where development is constructed with the water environment in mind. Water sensitive urban design applies at all scales and is a holistic concept. In Christchurch larger-scale multi-value stormwater management solutions were incorporated into rapidly developed greenfield sites on the city’s outskirts and in satellite towns, as they had been pre-earthquake. Individual properties on greenfield sites and within the city, however, continued to be constructed without water sensitive features such as rainwater tanks or living roofs. This research uses semi-structured interviews, policy analysis, and findings from local and international studies to investigate the benefits of building-scale WSUD and the barriers that have resulted in their absence. Although several inter-related barriers became apparent, cost, commonly cited as a barrier to sustainable development in general, was strongly represented. However, it is argued that the issue is one of mindset rather than cost. Solutions are proposed, based on international and national experience, that will demonstrate the benefits of adopting water sensitive urban design principles including at the building scale, and thereby build public and political support. The research is timely - there is still much development to occur, and increasing pressures from urban densification, population growth and climate change to mitigate.
We examine the role of business interruption (BI) insurance in business recovery following the Christchurch earthquake in 2011. First, we ask whether BI insurance increases the likelihood of business survival in the immediate (3-6 months) aftermath of a disaster. We find positive but statistically insignificant evidence that those firms that had incurred damage, but were covered by BI insurance, had higher likelihood of survival post-quake compared with those firms that did not have any insurance. For the medium-term (2-3 years) survival of firms, our results show a more explicit role for insurance. Firms with BI insurance experience increased productivity and improved performance following a catastrophe. Furthermore, we find that those organisations that receive prompt and full payments of their claims have a better recovery than those that had protracted or inadequate claims payments, but this difference between the two groups is not statistically significant. We find no statistically significant evidence that the latter group (inadequate payment) did any better than those organisations that had damage but no insurance coverage. In general, our analysis indicates the importance not only of adequate insurance coverage, but also of an insurance system that delivers prompt claim payments.
This is a post-peer-review, pre-copyedit version of an article published in 'The Geneva Papers on Risk and Insurance - Issues and Practice'. The final authenticated version is available online at: https://doi.org/10.1057/s41288-017-0067-y. The following terms of use apply: https://www.springer.com/gp/open-access/publication-policies/aam-terms-of-use.
The Stone Jug Fault (SJF) ruptured during the November 14th, 2016 (at 12:02 am), Mw 7.8 Kaikōura Earthquake which initiated ~40 km west-southwest of the study area, at a depth of approximately 15 km. Preliminary post-earthquake mapping indicated that the SJF connects the Conway-Charwell and Hundalee faults, which form continuous surface rupture, however, detailed study of the SJF had not been undertaken prior to this thesis due to its remote location and mountainous topography. The SJF is 19 km long, has an average strike of ~160° and generally carries approximately equal components of sinistral and reverse displacement. The primary fault trace is sigmoidal in shape with the northern and southern tips rotating in strike from NNW to NW, as the SJF approaches the Hope and Hundalee faults. It comprises several steps and bends and is associated with many (N=48) secondary faults, which are commonly near irregularities in the main fault geometry and in a distributed fault zone at the southern tip. The SJF is generally parallel to Torlesse basement bedding where it may utilise pre-existing zones of weakness. Horizontal, vertical and net displacements range up to 1.4 m, with displacement profiles along the primary trace showing two main maxima separated by a minima towards the middle and ends of the fault. Average net displacement along the primary trace is ~0.4m, with local changes in relative values of horizontal and vertical displacement at least partly controlled by fault strike. Two trenches excavated across the northern segment of the fault revealed displacement of mainly Holocene stratigraphy dated using radiocarbon (N=2) and OSL (N=4) samples. Five surface-rupturing paleoearthquakes displaying vertical displacements of <1 m occurred at: 11,000±1000, 7500±1000, 6500±1000, 3500±100 and 3 (2016 Kaikōura) years BP. These events produce an average slip rate since ~11 ka of 0.2-0.4 mm/yr and recurrence intervals of up to 5500 years with an average recurrence interval of 2750 yrs. Comparison of these results with unpublished trench data suggests that synchronous rupture of the Hundalee, Stone Jug, Conway-Charwell, and Humps faults at ~3500 yrs BP cannot be discounted and it is possible that multi-fault ruptures in north Canterbury are more common than previously thought.
Spatial variations in river facies exerted a strong influence on the distribution of liquefaction features observed in Christchurch during the 2010-11 Canterbury Earthquake Sequence (CES). Liquefaction and liquefaction-induced ground deformation was primarily concentrated near modern waterways and areas underlain by Holocene fluvial deposits with shallow water tables (< 1 to 2 m). In southern Christchurch, spatial variations of liquefaction and subsidence were documented in the suburbs within inner meander loops of the Heathcote River. Newly acquired geospatial data, geotechnical reports and eye-witness discussions are compiled to provide a detailed account of the surficial effects of CES liquefaction and ground deformation adjacent to the Heathcote River. LiDAR data and aerial photography are used to produce a new series of original figures which reveal the locations of recurrent liquefaction and subsidence. To investigate why variable liquefaction patterns occurred, the distribution of surface ejecta and associated ground damage is compared with near-surface sedimentologic, topographic, and geomorphic variability to seek relationships between the near-surface properties and observed ground damages. The most severe liquefaction was concentrated within a topographic low in the suburb of St Martins, an inner meander loop of the Heathcote River, with liquefaction only minor or absent in the surrounding areas. Subsurface investigations at two sites in St Martins enable documentation of fluvial stratigraphy, the expressions of liquefaction, and identification of pre-CES liquefaction features. Excavation to water table depths (~1.5 m below the surface) across sand boils reveals multiple generations of CES liquefaction dikes and sills that cross-cut Holocene fluvial and anthropogenic stratigraphy. Based on in situ geotechnical tests (CPT) indicating sediment with a factor of safety < 1, the majority of surface ejecta was sourced from well-sorted fine to medium sand at < 5 m depth, with the most damaging liquefaction corresponding with the location of a low-lying sandy paleochannel, a remnant river channel from the Holocene migration of the meander in St Martins. In the adjacent suburb of Beckenham, where migration of the Heathcote River has been laterally confined by topography associated with the volcanic lithologies of Banks Peninsula, severe liquefaction was absent with only minor sand boils occurring closest to the modern river channel. Auger sampling across the suburb revealed thick (>1 m) clay-rich overbank and back swamp sediments that produced a stratigraphy which likely confined the units susceptible to liquefaction and prevented widespread ejection of liquefied material. This analysis suggests river migration promotes the formation and preservation of fluvial deposits prone to liquefaction. Trenching revealed the strongest CES earthquakes with large vertical accelerations favoured sill formation and severe subsidence at highly susceptible locations corresponding with an abandoned channel. Less vulnerable sites containing deeper and thinner sand bodies only liquefied in the strongest and most proximal earthquakes forming minor localised liquefaction features. Liquefaction was less prominent and severe subsidence was absent where lateral confinement of a Heathcote meander has promoted the formation of fluvial stratum resistant to liquefaction. Correlating CES liquefaction with geomorphic interpretations of Christchurch’s Heathcote River highlights methods in which the performance of liquefaction susceptibility models can be improved. These include developing a reliable proxy for estimating soil conditions in meandering fluvial systems by interpreting the geology and geomorphology, derived from LiDAR data and modern river morphology, to improve the methods of accounting for the susceptibility of an area. Combining geomorphic interpretations with geotechnical data can be applied elsewhere to identify regional liquefaction susceptibilities, improve existing liquefaction susceptibility datasets, and predict future earthquake damage.
An as-built reinforced concrete (RC) frame building designed and constructed according to pre-1970s code design construction practice has been recently tested on the shake table at the University of Canterbury. The specimen, 1/2.5 scaled version of the original prototype, consists of two 3-storey 2-bay asymmetric frames in parallel, one interior and one exterior, jointed together by transverse beams and floor slabs. Following the benchmark test, a retrofit intervention has been proposed to rehabilitate the tested specimen. In this paper, detailed information on the assessment and design of the seismic retrofit procedure using GFRP (glass fibre reinforced polymer) materials is given for the whole frame. Hierarchy of strength and sequence of events (damage mechanisms) in the panel zone region are evaluated using a moment-axial load (M-N) interaction performance domain, according to a performance-based retrofit philosophy. Specific limit states or design objectives are targeted with attention given to both strength and deformation limits. In addition, an innovative retrofit solution using FRP anchor dowels for the corner beam-column joints with slabs is proposed. Finally, in order to provide a practical tool for engineering practice, the retrofit procedure is provided in a step-by step flowchart fashion.
The purpose of this paper is to empirically investigate the effects of a major disaster on the management of human resources in the construction sector. It sets out to identify the construction skills challenges and the factors that affected skills availability following the 2010/2011 earthquakes in Christchurch. It is hoped that this study will provide insights for on-going reconstruction and future disaster response with respect to the problem of skills shortages. Design/methodology/approach A triangulation method was adopted. The quantitative method, namely, a questionnaire survey, was employed to provide a baseline description. Field observations and interviews were used as a follow-up to ascertain issues and potential shortages over time. Three focus groups in the form of research workshops were convened to gain further insight into the feedback and to investigate the validity and applicability of the research findings. Findings The earthquakes in Christchurch had compounded the pre-existing skills shortages in the country due to heightened demand from reconstruction. Skills shortages primarily existed in seismic assessment and design for land and structures, certain trades, project management and site supervision. The limited technical capability available nationally, shortage of temporary accommodation to house additional workers, time needed for trainees to become skilled workers, lack of information about reconstruction workloads and lack of operational capacity within construction organisations, were critical constraints to the resourcing of disaster recovery projects. Research limitations/implications The research findings contribute to the debate on skills issues in construction. The study provides evidence that contributes to an improved understanding of the industry’s skills vulnerability and emerging issues that would likely exist after a major disaster in a resource-limited country such as New Zealand. Practical implications From this research, decision makers and construction organisations can gain a clear direction for improving the construction capacity and capability for on-going reconstruction. Factors that affected the post-earthquake skills availability can be considered by decision makers and construction organisations in their workforce planning for future disaster events. The recommendations will assist them in addressing skills shortages for on-going reconstruction. Originality/value Although the study is country-specific, the findings show the nature and scale of skills challenges the construction industry is likely to face following a major disaster, and the potential issues that may compound skills shortages. It provides lessons for other disaster-prone countries where the resource pool is small and a large number of additional workers are needed to undertake reconstruction.
During the past two decades, the focus has been on the need to provide communities with structures that undergo minimal damage after an earthquake event while still being cost competitive. This has led to the development of high performance seismic resisting systems, and advances in design methodologies, in order respect this demand efficiently. This paper presents the experimental response of four pre-cast, post-tensioned rocking wall systems tested on the shake-table at the University of Canterbury. The wall systems were designed as a retrofit solution for an existing frame building, but are equally applicable for use in new design. Design of the wall followed a performance-based retrofit strategy in which structural limit states appropriate to both the post-tensioned wall and the existing building were considered. Dissipation for each of the four post-tensioned walls was provided via externally mounted devices, located in parallel to post-tensioned tendons for re-centring. This allowed the dissipation devices to be easily replaced or inspected following a major earthquake. Each wall was installed with viscous fluid dampers, tension-compression yielding steel dampers, a combination of both or no devices at all – thus relying on contact damping alone. The effectiveness of both velocity and displacement dependant dissipation are investigated for protection against far-field and velocity-pulse ground motion characteristics. The experimental results validate the behaviour of ‘Advanced Flag-Shape’ rocking, dissipating solutions which have been recently proposed and numerically tested. Maximum displacements and material strains were well controlled and within acceptable bounds, and residual deformations were minimal due to the re-centring contribution from the post-tensioned tendons. Damage was confined to inelastic yielding (or fluid damping) of the external dampers.
One of the most controversial issues highlighted by the 2010-2011 Christchurch earthquake series and more recently the 2016 Kaikoura earthquake, has been the evident difficulty and lack of knowledge and guidelines for: a) evaluation of the residual capacity damaged buildings to sustain future aftershocks; b) selection and implementation of a series of reliable repairing techniques to bring back the structure to a condition substantially the same as prior to the earthquake; and c) predicting the cost (or cost-effectiveness) of such repair intervention, when compared to fully replacement costs while accounting for potential aftershocks in the near future. As a result of such complexity and uncertainty (i.e., risk), in combination with the possibility (unique in New Zealand when compared to most of the seismic-prone countries) to rely on financial support from the insurance companies, many modern buildings, in a number exceeding typical expectations from past experiences at an international level, have ended up being demolished. This has resulted in additional time and indirect losses prior to the full reconstruction, as well as in an increase in uncertainty on the actual relocation of the investment. This research project provides the main end-users and stakeholders (practitioner engineers, owners, local and government authorities, insurers, and regulatory agencies) with comprehensive evidence-based information to assess the residual capacity of damage reinforced concrete buildings, and to evaluate the feasibility of repairing techniques, in order to support their delicate decision-making process of repair vs. demolition or replacement. Literature review on effectiveness of epoxy injection repairs, as well as experimental tests on full-scale beam-column joints shows that repaired specimens have a reduced initial stiffness compared with the undamaged specimen, with no apparent strength reduction, sometimes exhibiting higher displacement ductility capacities. Although the bond between the steel and concrete is only partially restored, it still allows the repaired specimen to dissipate at least the same amount of hysteretic energy. Experimental tests on buildings subjected to earthquake loading demonstrate that even for severe damage levels, the ability of the epoxy injection to restore the initial stiffness of the structure is significant. Literature review on damage assessment and repair guidelines suggests that there is consensus within the international community that concrete elements with cracks less than 0.2 mm wide only require cosmetic repairs; epoxy injection repairs of cracks less and 2.0 mm wide and concrete patching of spalled cover concrete (i.e., minor to moderate damage) is an appropiate repair strategy; and for severe damaged components (e.g., cracks greater than 2.0 mm wide, crushing of the concrete core, buckling of the longitudinal reinforcement) local replacement of steel and/or concrete in addition to epoxy crack injection is more appropriate. In terms of expected cracking patterns, non-linear finite element investigations on well-designed reinforced concrete beam-to-column joints, have shown that lower number of cracks but with wider openings are expected to occur for larger compressive concrete strength, f’c, and lower reinforcement content, ρs. It was also observed that the tensile concrete strength, ft, strongly affects the expected cracking pattern in the beam-column joints, the latter being more uniformly distributed for lower ft values. Strain rate effects do not seem to play an important role on the cracking pattern. However, small variations in the cracking pattern were observed for low reinforcement content as it approaches to the minimum required as per NZS 3101:2006. Simple equations are proposed in this research project to relate the maximum and residual crack widths with the steel strain at peak displacement, with or without axial load. A literature review on fracture of reinforcing steel due to low-cycle fatigue, including recent research using steel manufactured per New Zealand standards is also presented. Experimental results describing the influence of the cyclic effect on the ultimate strain capacity of the steel are also discussed, and preliminary equations to account for that effect are proposed. A literature review on the current practice to assess the seismic residual capacity of structures is also presented. The various factors affecting the residual fatigue life at a component level (i.e., plastic hinge) of well-designed reinforced concrete frames are discussed, and equations to quantify each of them are proposed, as well as a methodology to incorporate them into a full displacement-based procedure for pre-earthquake and post-earthquake seismic assessment.
