The Canterbury Earthquake Recovery Authority (CERA) and the Canterbury Lifeline Utilities Group have collaborated to assemble documented infra- structure-related learnings from the recent Canterbury earthquakes and other natural hazard events over the last 15 years (i.e. since publication of Risks and Realities). The project was led by the Centre for Advanced Engineering (CAE) and was undertaken to promote knowledge sharing by facilitating access to diverse documents on natural hazard learnings, a matter of ongoing relevance and very considerable current interest.
Environmental assessment in New Zealand is governed by the provisions of the Resource Management Act (RMA) 1991. The Act requires persons wishing to undertake certain activities to apply for resource consent from their local or regional council - a procedure termed the Resource Consent Process. The key component of a resource consent application is an Assessment of Environmental Effects (AEE) report; a statement of the environmental effects of a proposed activity. Problems arise when environmental assessments are complicated by uncertain and abnormal circumstances such as natural hazards. Natural hazards (including earthquakes, floods, tsunami, and coastal erosion) can be catastrophic to an environment. If hazards are not avoided or successfully mitigated, they can result in serious consequences to proposed development and to the environment which the proposal relates. The aim of this study is to assess the adequacy of the resource consent process (as outlined in the Resource Management Act 1991) for dealing with proposed development affected by natural hazards. This study reviews the context of the resource consent process for dealing with natural hazards to identify potential issues in the assessment process. Guidance criteria for assessing natural hazards (termed Natural Hazard Assessment) are developed to evaluate against two resource consent applications affected by natural hazards. The findings of the consent process review and case study evaluation are discussed to determine the adequacy of the consent process for dealing with natural hazards. From the review of the consent process it was evident that the process has a number of problems for accommodating natural hazards into the assessment. Although many important traits are provided for in the process, such traits are not always reflected in environmental assessments. Evaluation of two resource consent applications against the process of Natural Hazard Assessment (NHA) showed that these consent applications did not adequately detail key information relating to natural hazards. Many problems evident in these applications were not amended by the Consent Authorities in the review process and subsequently consent was granted to information-deficient applications. Problematic issues identified in this study include: • A distinct lack of guidance (legal or otherwise) for the applicant and Consent Authority regarding the boundaries of inclusion of an effect; • Deficiencies in planning documents are reflected in AEE reports, the review of the consent application and in the end-decision; • Under-utilisation of "experts" throughout the consent process; • Minimal identification and account for the degree of uncertainty throughout the consent process; • Resource consents are being granted even though information in consent applications, and the means for assessing the information is deficient. These issues reflect that decisions are not being made based on all elements involved in a potential hazard. Subsequently, the resource consent process is not adequate for dealing with all aspects of natural hazards. The Natural Hazard Assessment process provides educated assessment criteria to assess development affected by natural hazards. By accounting for the problems evident in the consent process, the introduction of a three-tier identification, risk and vulnerability assessment, and evaluation process to account for uncertainties, Natural Hazard Assessment provides a platform for a thorough assessment of natural hazards. The application of the principles of Natural Hazard Assessment to the consent applications affected by natural hazards showed that many key issues were not covered in the assessment under the consent process. The nature of a natural event is that one may not occur in a given region over many lifetimes, however they will occur at some stage and planning and environmental assessment needs to provide for the associated hazards. Implementation of Natural Hazard Assessment is needed to help provide answers for the problems experienced in the resource consent process. Natural Hazard Assessment would allow decision-makers to make informed judgements on the situation at hand, leading to better planning and land-use options. Change to current practice is needed, as following the current path of environmental assessment will be the hazard in the end.
Improving community resilience requires a way of thinking about the nature of a community. Two complementary aspects are proposed: the flows connecting the community with its surrounding environment and the resources the community needs for its ongoing life. The body of necessary resources is complex, with many interactions between its elements. A systems approach is required to understand the issues adequately. Community resilience is discussed in general terms together with strategies for improving it. The ideas are then illustrated and amplified by an extended case study addressing means of improving the resilience of a community on the West Coast of New Zealand to natural disasters. The case study is in two phases. The first relies on a mix of on-the-ground observations and constructed scenarios to provide recommendations for enhancing community resilience, while the second complements the first by developing a set of general lessons and issues to be addressed from observations of the Christchurch earthquakes of 2010 and 2011.
The Canterbury Region is susceptible to a variety of natural hazards, including earthquakes, landslides and climate hazards. Increasing population and tourism within the region is driving development pressures and as more and more development occurs, the risk from natural hazards increases. In order to avoid development occurring in unacceptably vulnerable locations, natural hazard assessments are required. This study is a reconnaissance natural hazard assessment of Lakes Lyndon, Coleridge and Tekapo. There is restricted potential for development at Lake Lyndon, because the land surrounding the lake is owned by the Crown and has a number of development restrictions. However, there is the potential for conservation or recreation-linked development to occur. There is more potential for development at Lake Coleridge. Most of the land surrounding the lake is privately owned and has less development restrictions. The majority of land surrounding Lake Tekapo is divided into Crown-owned pastoral leases, which are protected from development, such as subdivision. However, there are substantial areas around the lake, which are privately owned and, therefore, have potential for development. Earthquake, landslide and climate hazards are the main natural hazards threatening Lakes Lyndon, Coleridge and Tekapo. The lakes are situated in a zone of active earth deformation in which large and relatively frequent earthquakes are produced. A large number of active faults lie within 15 km of each lake, which are capable of producing M7 or larger earthquakes. Ground shaking, liquefaction, landslides, tsunami and seiches are among the consequences of earthquakes, all of which have the potential to cause severe damage to lives, lifelines and infrastructure. Landslides are also common in the landscape surrounding the lakes. The majority of slopes surrounding the lakes are at significant risk from earthquake-induced failure under moderate to strong earthquake shaking. This level of shaking is expected to occur in any 50 year period around Lakes Lyndon and Coleridge, and in any 150 year period around Lake Tekapo. Injuries, fatalities and property damage can occur directly from landslide impact or from indirect effects such as flooding from landslide-generated tsunami or from landslide dam outbreaks. Lakes Lyndon, Coleridge and Tekapo are also susceptible to climate hazards, such as high winds, drought, heavy snowfall and heavy rainfall, which can lead to landslides and flooding. Future climate change due to global warming is most likely going to affect patterns of frequency and magnitudes of extreme weather events, leading to an increase in climate hazards. Before development is permitted around the lakes, it is essential that each of these hazards is considered so that unacceptably vulnerable areas can be avoided.
Natural hazard reviews reveal increases in disaster impacts nowhere more pronounced than in coastal settlements. Despite efforts to enhance hazard resilience, the common trend remains to keep producing disaster prone places. This paper explicitly explores hazard versus multi-hazard concepts to illustrate how different conceptualizations can enhance or reduce settlement resilience. Understandings gained were combined with onthe-ground lessons from earthquake and flooding experiences to develop of a novel ‘first cut’ approach for analyzing key multi-hazard interconnections, and to evaluate resilience enhancing opportunities. Traditional disaster resilience efforts often consider different hazard types discretely. However, recent events in Christchurch, a New Zealand city that is part of the 100 Resilient Cities network, highlight the need to analyze the interrelated nature of different hazards, especially for enhancing lifelines system resilience. Our overview of the Christchurch case study demonstrates that seismic, hydrological, shallow-earth, and coastal hazards can be fundamentally interconnected, with catastrophic results where such interconnections go unrecognized. In response, we have begun to develop a simple approach for use by different stakeholders to support resilience planning, pre and post disaster, by: drawing attention to natural and built environment multi-hazard links in general; illustrating a ‘first cut’ tool for uncovering earthquake-flooding multi-hazard links in particular; and providing a basis for reviewing resilience strategy effectiveness in multi-hazard prone environments. This framework has particular application to tectonically active areas exposed to climate-change issues.
Anyone keeping a global tally of recent disasters is likely to be asking: What role will the hazards and disasters of coastal plains play in the lives and economies of 21st century humanity? In this article, we reflect on this question using examples of how different types of coastal land performed during the Christchurch and other earthquake events to examine the complex of coastal-tectonic hazards that are being constructed in the Tokyo megacity
The Master of Engineering Management Project was sponsored by the Canterbury Earthquake Recovery Authority (CERA) and consisted of two phases: The first was an analysis of existing information detailing the effects of hazardous natural events on Canterbury Lifeline Utilities in the past 15 years. The aim of this “Lessons Learned” project was to produce an analysis report that identified key themes from the research, gaps in the existing data and to provide recommendations from these “Lessons Learned.” The Second phase was the development of a practical “Disaster Mitigation Guideline” that outlined lessons in the field of Emergency Sanitation. This research would build upon the first stage and would draw from international reference to develop a guideline that has practical implementation possibilities throughout the world.
This book is the result of an investigation into the vulnerability of the infrastructure serving metropolitan Christchurch (including Lyttelton). The work was undertaken by the Christchurch Engineering Lifelines Group and the objectives are: to identify the vulnerability of engineering lifeline services to damage from earthquakes, flooding, tsunami and meteorological hazards; to identify practical engineering strategies for reducing the risk or impact of such damage and for providing for reinstatement following such events; and to communicate the issues to people involved in the management of these services and to raise the awareness of the public to their importance.
This report forms part of a research project examining rural community resilience to natural hazard events, with a particular focus on transient population groups. A preliminary desktop and scoping exercise was undertaken to examine nine communities affected by the Kaikoura earthquake and to identify the variety of transient population groups that are commonly (and increasingly) found in rural New Zealand (see Wilson & Simmons, 2017). From this, four case study communities – Blenheim, Kaikoura, Waiau and St Arnaud – were selected to represent a range of settlement types. These communities varied in respect of social, economic and geographic features, including the presence of particular transient population groups, and earthquake impact. While the 2016 Kaikoura earthquake provided a natural hazard event on which to focus the research, the research interest was in long-term (and broad) community resilience, rather than short-term (and specific) response and recovery actions which occurred post-earthquake.
This report provides an initial overview and gap analysis of the multi-hazards interactions that might affect fluvial and pluvial flooding (FPF) hazard in the Ōpāwaho Heathcote catchment. As per the terms of reference, this report focuses on a one-way analysis of the potential effects of multi-hazards on FPF hazard, as opposed to a more complex multi-way analysis of interactions between all hazards. We examined the relationship between FPF hazard and hazards associated with the phenomena of tsunamis; coastal erosion; coastal inundation; groundwater; earthquakes; and mass movements. Tsunamis: Modelling research indicates the worst-case tsunami scenarios potentially affecting the Ōpāwaho Heathcote catchment are far field. Under low probability, high impact tsunami scenarios waves could travel into Pegasus Bay and the Avon-Heathcote Estuary Ihutai, reaching the mouth and lower reaches of the Heathcote catchment and river, potentially inundating and eroding shorelines in sub-catchments 1 to 5, and temporarily blocking fluvial drainage more extensively. Any flooding infrastructure or management actions implemented in the area of tsunami inundation would ideally be resilient to tsunami-induced inundation and erosion. Model results currently available are a first estimate of potential tsunami inundation under contemporary sea and land level conditions. In terms of future large tsunami events, these models likely underestimate effects in riverside sub-catchments, as well as effects under future sea level, shoreline and other conditions. Also of significance when considering different FPF management structures, it is important to be mindful that certain types of flood structures can ‘trap’ inundating water coming from ocean directions, leading to longer flood durations and salinization issues. Coastal erosion: Model predictions indicate that sub-catchments 1 to 3 could potentially be affected by coastal erosion by the timescale of 2065, with sub-catchments 1-6 predicted to be potentially affected by coastal erosion by the time scale of 2115. In addition, the predicted open coast effects of this hazard should not be ignored since any significant changes in the New Brighton Spit open coast would affect erosion rates and exposure of the landward estuary margins, including the shorelines of the Ōpāwaho Heathcote catchment. Any FPF flooding infrastructure or management activities planned for the potentially affected sub-catchments needs to recognise the possibility of coastal erosion, and to have a planned response to the predicted potential shoreline translation. Coastal inundation: Model predictions indicate coastal inundation hazards could potentially affect sub-catchments 1 to 8 by 2065, with a greater area and depth of inundation possible for these same sub-catchments by 2115. Low-lying areas of the Ōpāwaho Heathcote catchment and river channel that discharge into the estuary are highly vulnerable to coastal inundation since elevated ocean and estuary water levels can block the drainage of inland systems, compounding FPF hazards. Coastal inundation can overwhelm stormwater and other drainage network components, and render river dredging options ineffective at best, flood enhancing at worst. A distinction can be made between coastal inundation and coastal erosion in terms of the potential impacts on affected land and assets, including flood infrastructure, and the implications for acceptance, adaptation, mitigation, and/or modification options. That is, responding to inundation could include structural and/or building elevation solutions, since unlike erosion, inundation does not necessarily mean the loss of land. Groundwater: Groundwater levels are of significant but variable concern when examining flooding hazards and management options in the Ōpāwaho Heathcote catchment due to variability in soils, topographies, elevations and proximities to riverine and estuarine surface waterbodies. Much of the Canterbury Plains part of the Ōpāwaho Heathcote catchment has a water table that is at a median depth of <1m from the surface (with actual depth below surface varying seasonally, inter-annually and during extreme meteorological events), though the water table depth rapidly shifts to >6m below the surface in the upper Plains part of the catchment (sub-catchments 13 to 15). Parts of Waltham/Linwood (sub-catchments 5 & 6) and Spreydon (sub-catchment 10) have extensive areas with a particularly high water table, as do sub-catchments 18, 19 and 20 south of the river. In all of the sub-catchments where groundwater depth below surface is shallow, it is necessary to be mindful of cascading effects on liquefaction hazard during earthquake events, including earthquake-induced drainage network and stormwater infrastructure damage. In turn, subsidence induced by liquefaction and other earthquake processes during the CES directly affected groundwater depth below surface across large parts of the central Ōpāwaho Heathcote catchment. The estuary margin of the catchment also faces increasing future challenges with sea level rise, which has the potential to elevate groundwater levels in these areas, compounding existing liquefaction and other earthquake associated multi-hazards. Any increases in subsurface runoff due to drainage system, development or climate changes are also of concern for the loess covered hill slopes due to the potential to enhance mass movement hazards. Earthquakes: Earthquake associated vertical ground displacement and liquefaction have historically affected, or are in future predicted to affect, all Ōpāwaho Heathcote sub-catchments. During the CES, these phenomena induced a significant cascades of changes in the city’s drainage systems, including: extensive vertical displacement and liquefaction induced damage to stormwater ‘greyware’, reducing functionality of the stormwater system; damage to the wastewater system which temporarily lowered groundwater levels and increased stormwater drainage via the wastewater network on the one hand, creating a pollution multi-hazard for FPF on the other hand; liquefaction and vertical displacement induced river channel changes affected drainage capacities; subsidence induced losses in soakage and infiltration capacities; changes occurred in topographic drainage conductivity; estuary subsidence (mainly around the Ōtākaro Avon rivermouth) increased both FPF and coastal inundation hazards; estuary bed uplift (severe around the Ōpāwaho Heathcote margins), reduced tidal prisms and increased bed friction, producing an overall reduction the waterbody’s capacity to efficiently flush catchment floodwaters to sea; and changes in estuarine and riverine ecosystems. All such possible effects need to be considered when evaluating present and future capacities of the Ōpāwaho Heathcote catchment FPF management systems. These phenomena are particularly of concern in the Ōpāwaho Heathcote catchment since stormwater networks must deal with constraints imposed by stream and river channels (past and present), estuarine shorelines and complex hill topography. Mass movements: Mass movements are primarily a risk in the Port Hills areas of the Ōpāwaho Heathcote catchment (sub-catchments 1, 2, 7, 9, 11, 16, 21), though there are one or two small but susceptible areas on the banks of the Ōpāwaho Heathcote River. Mass movements in the form of rockfalls and debris flows occurred on the Port Hills during the CES, resulting in building damage, fatalities and evacuations. Evidence has also been found of earthquake-triggered tunnel gully collapsesin all Port Hill Valleys. Follow-on effects of these mass movements are likely to occur in major future FPF and other hazard events. Of note, elevated groundwater levels, coastal inundation, earthquakes (including liquefaction and other effects), and mass movement exhibit the most extensive levels of multi-hazard interaction with FPF hazard. Further, all of the analysed multi-hazard interactions except earthquakes were found to consistently produce increases in the FPF hazard. The implications of these analyses are that multihazard interactions generally enhance the FPF hazard in the Ōpāwaho Heathcote catchment. Hence, management plans which exclude adjustments for multi-hazard interactions are likely to underestimate the FPF hazard in numerous different ways. In conclusion, although only a one-way analysis of the potential effects of selected multi-hazards on FPF hazard, this review highlights that the Ōpāwaho Heathcote catchment is an inherently multi- hazard prone environment. The implications of the interactions and process linkages revealed in this report are that several significant multi-hazard influences and process interactions must be taken into account in order to design a resilient FPF hazard management strategy.
Artificial Neural Networks (ANN) as a tool offers opportunities for modeling the inherent complexity and uncertainty associated with socio-environmental systems. This study draws on New Zealand ski fields (multiple locations) as socio- environmental systems while considering their perceived resilience to low probability but potential high consequences catastrophic natural events (specifically earthquakes). We gathered data at several ski fields using a mixed methodology including: geomorphic assessment, qualitative interviews, and an adaptation of Ozesmi and Ozesmi’s (2003) multi-step fuzzy cognitive mapping (FCM) approach. The data gathered from FCM are qualitatively condensed, and aggregated to three different participant social groups. The social groups include ski fields users, ski industry workers, and ski field managers. Both quantitative and qualitative indices are used to analyze social cognitive maps to identify critical nodes for ANN simulations. The simulations experiment with auto-associative neural networks for developing adaptive preparation, response and recovery strategies. Moreover, simulations attempt to identify key priorities for preparation, response, and recovery for improving resilience to earthquakes in these complex and dynamic environments. The novel mixed methodology is presented as a means of linking physical and social sciences in high complexity, high uncertainty socio-environmental systems. Simulation results indicate that participants perceived that increases in Social Preparation Action, Social Preparation Resources, Social Response Action and Social Response Resources have a positive benefit in improving the resilience to earthquakes of ski fields’ stakeholders.
This paper examines the consistency of seismicity and ground motion models, used for seismic hazard analysis in New Zealand, with the observations in the Canterbury earthquakes. An overview is first given of seismicity and ground motion modelling as inputs of probabilistic seismic hazard analysis, whose results form the basis for elastic response spectra in NZS1170.5:2004. The magnitude of earthquakes in the Canterbury earthquake sequence are adequately allowed for in the current NZ seismicity model, however the consideration of ‘background’ earthquakes as point sources at a minimum depth of 10km results in up to a 60% underestimation of the ground motions that such events produce. The ground motion model used in conventional NZ seismic hazard analysis is shown to provide biased predictions of response spectra (over-prediction near T=0.2s , and under-predictions at moderate-to-large vibration periods). Improved ground motion prediction can be achieved using more recent NZ-specific models.
Recycling is often employed as part of a disaster waste management system. However, the feasibility, method and effectiveness of recycling varies between disaster events. This qualitative study is based on literature reviews, expert interviews and active participatory research of five international disaster events in developed countries (2009 Victorian Bushfires, Australia; 2009 L’Aquila earthquake, Italy; 2005 Hurricane Katrina, United States; 2010 and 2011 Canterbury earthquakes, New Zealand; 2011 Great East Japan earthquake) to answer three questions: What are the main factors that affect the feasibility of recycling post-disaster? When is on-site or off-site separation more effective? What management approaches improve recycling effectiveness? Seven disaster-specific factors need to be assessed to determine the feasibility of disaster waste recycling programmes: volume of waste; degree of mixing of waste; human and environmental health hazards; areal extent of the waste; community priorities; funding mechanisms; and existing and disaster-specific regulations. The appropriateness of on or off-site waste separation depends on four factors: time constraints; resource availability; degree of mixing of waste and human and public health hazards. Successful recycling programmes require good management including clear and well enforced policies (through good contracts or regulations) and pre-event planning. Further research into post-disaster recycling markets, funding mechanisms and recycling in developing countries is recommended.
The purpose of this thesis is to conduct a detailed examination of the forward-directivity characteristics of near-fault ground motions produced in the 2010-11 Canterbury earthquakes, including evaluating the efficacy of several existing empirical models which form the basis of frameworks for considering directivity in seismic hazard assessment. A wavelet-based pulse classification algorithm developed by Baker (2007) is firstly used to identify and characterise ground motions which demonstrate evidence of forward-directivity effects from significant events in the Canterbury earthquake sequence. The algorithm fails to classify a large number of ground motions which clearly exhibit an early-arriving directivity pulse due to: (i) incorrect pulse extraction resulting from the presence of pulse-like features caused by other physical phenomena; and (ii) inadequacy of the pulse indicator score used to carry out binary pulse-like/non-pulse-like classification. An alternative ‘manual’ approach is proposed to ensure 'correct' pulse extraction and the classification process is also guided by examination of the horizontal velocity trajectory plots and source-to-site geometry. Based on the above analysis, 59 pulse-like ground motions are identified from the Canterbury earthquakes , which in the author's opinion, are caused by forward-directivity effects. The pulses are also characterised in terms of their period and amplitude. A revised version of the B07 algorithm developed by Shahi (2013) is also subsequently utilised but without observing any notable improvement in the pulse classification results. A series of three chapters are dedicated to assess the predictive capabilities of empirical models to predict the: (i) probability of pulse occurrence; (ii) response spectrum amplification caused by the directivity pulse; (iii) period and amplitude (peak ground velocity, PGV) of the directivity pulse using observations from four significant events in the Canterbury earthquakes. Based on the results of logistic regression analysis, it is found that the pulse probability model of Shahi (2013) provides the most improved predictions in comparison to its predecessors. Pulse probability contour maps are developed to scrutinise observations of pulses/non-pulses with predicted probabilities. A direct comparison of the observed and predicted directivity amplification of acceleration response spectra reveals the inadequacy of broadband directivity models, which form the basis of the near-fault factor in the New Zealand loadings standard, NZS1170.5:2004. In contrast, a recently developed narrowband model by Shahi & Baker (2011) provides significantly improved predictions by amplifying the response spectra within a small range of periods. The significant positive bias demonstrated by the residuals associated with all models at longer vibration periods (in the Mw7.1 Darfield and Mw6.2 Christchurch earthquakes) is likely due to the influence of basin-induced surface waves and non-linear soil response. Empirical models for the pulse period notably under-predict observations from the Darfield and Christchurch earthquakes, inferred as being a result of both the effect of nonlinear site response and influence of the Canterbury basin. In contrast, observed pulse periods from the smaller magnitude June (Mw6.0) and December (Mw5.9) 2011 earthquakes are in good agreement with predictions. Models for the pulse amplitude generally provide accurate estimates of the observations at source-to-site distances between 1 km and 10 km. At longer distances, observed PGVs are significantly under-predicted due to their slower apparent attenuation. Mixed-effects regression is employed to develop revised models for both parameters using the latest NGA-West2 pulse-like ground motion database. A pulse period relationship which accounts for the effect of faulting mechanism using rake angle as a continuous predictor variable is developed. The use of a larger database in model development, however does not result in improved predictions of pulse period for the Darfield and Christchurch earthquakes. In contrast, the revised model for PGV provides a more appropriate attenuation of the pulse amplitude with distance, and does not exhibit the bias associated with previous models. Finally, the effects of near-fault directivity are explicitly included in NZ-specific probabilistic seismic hazard analysis (PSHA) using the narrowband directivity model of Shahi & Baker (2011). Seismic hazard analyses are conducted with and without considering directivity for typical sites in Christchurch and Otira. The inadequacy of the near-fault factor in the NZS1170.5: 2004 is apparent based on a comparison with the directivity amplification obtained from PSHA.
Small, tight-knit communities, are complex to manage from outside during a disaster. The township of Lyttelton, New Zealand, and the communities of Corsair Bay, Cass Bay, and Rapaki to the east, are especially more so difficult due to the terrain that encloses them, which caused them to be cut-off from Christchurch, the largest city in the South Island, barely 10 km away, after the Mw 7.1 Darfield Earthquake and subsequent Canterbury Earthquake Sequence. Lyttelton has a very strong and deep-rooted community spirit that draws people to want to be a part of Lyttelton life. It is predominantly residential on the slopes, with retail space, service and light industry nestled near the harbour. It has heritage buildings stretching back to the very foundation of Canterbury yet hosts the largest, modern deep-water port for the region. This study contains two surveys: one circulated shortly before the Darfield Earthquake and one circulated in July 2011, after the Christchurch and Sumner Earthquakes. An analytical comparison of the participants’ household preparedness for disaster before the Darfield Earthquake and after the Christchurch and Sumner Earthquakes was performed. A population spatiotemporal distribution map was produced that shows the population in three-hourly increments over a week to inform exposure to vulnerability to natural hazards. The study went on to analyse the responses of the participants in the immediate period following the Chrsitchurch and Sumner Earthquakes, including their homeward and subsequent journeys, and the decision to evacuate or stay in their homes. Possible predictors to a decision to evacuate some or all members of the household were tested. The study also asked participants’ views on the events since September 2010 for analysis.
On 22 February 2011，a magnitude Mw 6.3 earthquake occurred with an epicenter located near Lyttelton at about 10km from Christchurch in Canterbury region on the South Island of New Zealand (Figure 1). Since this earthquake occurred in the midst of the aftershock activity which had continued since the 4 September 2010 Darfield Earthquake occurrence, it was considered to be an aftershock of the initial earthquake. Because of the short distance to the city and the shallower depth of the epicenter, this earthquake caused more significant damage to pipelines, traffic facilities, residential houses/properties and multi-story buildings in the central business district than the September 2010 Darfield Earthquake in spite of its smaller earthquake magnitude. Unfortunately, this earthquake resulted in significant number of casualties due to the collapse of multi-story buildings and unreinforced masonry structures in the city center of Christchurch. As of 4 April, 172 casualties were reported and the final death toll is expected to be 181. While it is extremely regrettable that Christchurch suffered a terrible number of victims, civil and geotechnical engineers have this hard-to-find opportunity to learn the response of real ground from two gigantic earthquakes which occurred in less than six months from each other. From geotechnical engineering point of view, it is interesting to discuss the widespread liquefaction in natural sediments, repeated liquefaction within short period and further damage to earth structures which have been damaged in the previous earthquake. Following the earthquake, an intensive geotechnical reconnaissance was conducted to capture evidence and perishable data from this event. The team included the following members: Misko Cubrinovski (University of Canterbury, NZ, Team Leader), Susumu Yasuda (Tokyo Denki University, Japan, JGS Team Leader), Rolando Orense (University of Auckland, NZ), Kohji Tokimatsu (Tokyo Institute of Technology, Japan), Ryosuke Uzuoka (Tokushima University, Japan), Takashi Kiyota (University of Tokyo, Japan), Yasuyo Hosono (Toyohashi University of Technology, Japan) and Suguru Yamada (University of Tokyo, Japan).
A team of earthquake geologists, seismologists and engineering seismologists from GNS Science, NIWA, University of Canterbury, and Victoria University of Wellington have collectively produced an update of the 2002 national probabilistic seismic hazard (PSH) model for New Zealand. The new model incorporates over 200 new onshore and offshore fault sources, and utilises newly developed New Zealand-based scaling relationships and methods for the parameterisation of the fault and subduction interface sources. The background seismicity model has also been updated to include new seismicity data, a new seismicity regionalisation, and improved methodology for calculation of the seismicity parameters. Background seismicity models allow for the occurrence of earthquakes away from the known fault sources, and are typically modelled as a grid of earthquake sources with rate parameters assigned from the historical seismicity catalogue. The Greendale Fault, which ruptured during the M7.1, 4 September 2010 Darfield earthquake, was unknown prior to the earthquake. However, the earthquake was to some extent accounted for in the PSH model. The maximum magnitude assumed in the background seismicity model for the area of the earthquake is 7.2 (larger than the Darfield event), but the location and geometry of the fault are not represented. Deaggregations of the PSH model for Christchurch at return periods of 500 years and above show that M7-7.5 fault and background source-derived earthquakes at distances less than 40 km are important contributors to the hazard. Therefore, earthquakes similar to the Darfield event feature prominently in the PSH model, even though the Greendale Fault was not an explicit model input.
On the second day of teaching for 2011, the University of Canterbury (UC) faced the most significant crisis of its 138-year history. After being shaken severely by a magnitude 7.1 earthquake on 4 September 2010, UC felt it was well along the pathway to getting back to ‘normal’. That all changed at 12:51pm on 22 February 2011, when Christchurch city was hit by an even more devastating event. A magnitude 6.3 (Modified Mercalli intensity ten – MM X) earthquake, just 13km south-east of the Christchurch city centre, caused vertical peak ground accelerations amongst the highest ever recorded in an urban environment, in some places more than twice the acceleration due to gravity. The earthquake caused immediate evacuation of the UC campus and resulted in significant damage to many buildings. Thankfully there were no serious injuries or fatalities on campus, but 185 people died in the city and many more suffered serious injuries. At the time of writing, eighteen months after the first earthquake in September, Christchurch is still experiencing regular earthquakes. Seismologists warn that the region may experience heightened seismicity for a decade or more. While writing this report we have talked with many different people from across the University. People’s experiences are different and we have not managed to talk with everyone, but we hope that by drawing together many different perspectives from across the campus that this report will serve two purposes; to retain our institutional memory of what we have learnt over the past eighteen months, and also to share our learnings with other organisations in New Zealand and around the world who, we hope, will benefit from learning about our experience.
Effective management of waste and debris generated by a disaster event is vital to ensure rapid and efficient response and recovery that supports disaster risk reduction (DRR). Disaster waste refers to any stream of debris that is created from a natural disaster that impacts the environment, infrastructure, and property. This waste can be problematic due to extensive volumes, environmental contamination and pollution, public health risks, and the disruption of response and recovery efforts. Due to the complexities in dealing with these diverse and voluminous materials, having disaster waste management (DWM) planning in place pre-event is crucial. In particular, coordinated, interagency plans that have been informed by estimates of waste volumes and types are vital to ensure management facilities, personnel, and recovery resources do not become overwhelmed. Globally, a priority when formulating DWM plans is the robust estimation of disaster waste stream types and volumes. This is a relatively under-researched area, despite the growing risk of natural disasters and increasingly inadequate waste management facilities. In Aotearoa New Zealand, a nation-wide DWM planning tool has been proposed for local government use, and waste amounts from events such as the Christchurch Earthquakes have been estimated. However, there has been little work undertaken to estimate waste types and volumes with a region-specific, multi-hazard focus, which is required to facilitate detailed regional DWM planning. This research provides estimates of potential disaster waste volumes and types in the Waitaha-Canterbury region of the South Island (Te Waipounamu) for three key hazard scenarios: a M8.0 Alpine Fault earthquake with a south-to-north rupture pattern, a far-sourced tsunami using a maximum credible event model for a Peru-sourced event, and major flooding using geospatial datasets taken from available local government modelling. Conducted in partnership with Environment Canterbury and Canterbury CDEM, this estimation work informed stakeholder engagement through multi-agency workshops at the district level. This research was comprised of two key parts. The first was enhancing and extending a disaster waste estimation model used in Wellington and applying it to the Canterbury region to quantify waste volumes and types. The second part was using this model and its estimates to inform engagement with stakeholders in multi-agency, district-level workshops in Kaikōura, Hurunui, and Waimakariri. In these workshops, the waste estimates were used to catalyse discussion around potential issues associated with the management of disaster waste. Regionally, model estimates showed that the earthquake scenario would generate the highest total volume of disaster waste (1.94 million m³), compared to the tsunami scenario (1.89 million m³) and the flood scenario (173,900 m³). Flood waste estimates are likely underrepresented due to limited flood modelling coverage, but still provide a valuable comparison. Whilst waste estimates differ significantly between districts, waste volumes were shown to be not solely dependent on building/population density. The district-level workshops showed that DWM challenges revolved around logistical constraints, public concerns, governance complexities, and environmental issues. Future work should further enhance this estimation model and apply it to other regions of Aotearoa New Zealand, to help develop a set of cohesive DWM plans for each region. The waste estimation model could also be adapted and applied internationally. The findings from this research provide a foundation for advancing DWM planning and stakeholder engagement in the Waitaha-Canterbury region. By offering region-specific waste estimates across multiple hazard scenarios, this work supports district councils and emergency managers in developing informed, proactive strategies for disaster preparedness and response. The insights gained from district-level workshops highlight key challenges that must be addressed in future planning. These outcomes contribute to a broader research agenda for DWM in Aotearoa New Zealand, and offer a framework adaptable to international contexts.
The Canterbury Earthquake Sequence (CES) of 2010-2011 produced large seismic moments up to Mw 7.1. These large, near-to-surface (<15 km) ruptures triggered >6,000 rockfall boulders on the Port Hills of Christchurch, many of which impacted houses and affected the livelihoods of people within the impacted area. From these disastrous and unpredicted natural events a need arose to be able to assess the areas affected by rockfall events in the future, where it is known that a rockfall is possible from a specific source outcrop but the potential boulder runout and dynamics are not understood. The distribution of rockfall deposits is largely constrained by the physical properties and processes of the boulder and its motion such as block density, shape and size, block velocity, bounce height, impact and rebound angle, as well as the properties of the substrate. Numerical rockfall models go some way to accounting for all the complex factors in an algorithm, commonly parameterised in a user interface where site-specific effects can be calibrated. Calibration of these algorithms requires thorough field checks and often experimental practises. The purpose of this project, which began immediately following the most destructive rupture of the CES (February 22, 2011), is to collate data to characterise boulder falls, and to use this information, supplemented by a set of anthropogenic boulder fall data, to perform an in-depth calibration of the three-dimensional numerical rockfall model RAMMS::Rockfall. The thesis covers the following topics: • Use of field data to calibrate RAMMS. Boulder impact trails in the loess-colluvium soils at Rapaki Bay have been used to estimate ranges of boulder velocities and bounce heights. RAMMS results replicate field data closely; it is concluded that the model is appropriate for analysing the earthquake-triggered boulder trails at Rapaki Bay, and that it can be usefully applied to rockfall trajectory and hazard assessment at this and similar sites elsewhere. • Detailed analysis of dynamic rockfall processes, interpreted from recorded boulder rolling experiments, and compared to RAMMS simulated results at the same site. Recorded rotational and translational velocities of a particular boulder show that the boulder behaves logically and dynamically on impact with different substrate types. Simulations show that seasonal changes in soil moisture alter rockfall dynamics and runout predictions within RAMMS, and adjustments are made to the calibration to reflect this; suggesting that in hazard analysis a rockfall model should be calibrated to dry rather than wet soil conditions to anticipate the most serious outcome. • Verifying the model calibration for a separate site on the Port Hills. The results of the RAMMS simulations show the effectiveness of calibration against a real data set, as well as the effectiveness of vegetation as a rockfall barrier/retardant. The results of simulations are compared using hazard maps, where the maximum runouts match well the mapped CES fallen boulder maximum runouts. The results of the simulations in terms of frequency distribution of deposit locations on the slope are also compared with those of the CES data, using the shadow angle tool to apportion slope zones. These results also replicate real field data well. Results show that a maximum runout envelope can be mapped, as well as frequency distribution of deposited boulders for hazard (and thus risk) analysis purposes. The accuracy of the rockfall runout envelope and frequency distribution can be improved by comprehensive vegetation and substrate mapping. The topics above define the scope of the project, limiting the focus to rockfall processes on the Port Hills, and implications for model calibration for the wider scientific community. The results provide a useful rockfall analysis methodology with a defensible and replicable calibration process, that has the potential to be applied to other lithologies and substrates. Its applications include a method of analysis for the selection and positioning of rockfall countermeasure design; site safety assessment for scaling and demolition works; and risk analysis and land planning for future construction in Christchurch.
Coastal and river environments are exposed to a number of natural hazards that have the potential to negatively affect both human and natural environments. The purpose of this research is to explain that significant vulnerabilities to seismic hazards exist within coastal and river environments and that coasts and rivers, past and present, have played as significant a role as seismic, engineering or socio-economic factors in determining the impacts and recovery patterns of a city following a seismic hazard event. An interdisciplinary approach was used to investigate the vulnerability of coastal and river areas in the city of Christchurch, New Zealand, following the Canterbury Earthquake Sequence, which began on the 4th of September 2010. This information was used to identify the characteristics of coasts and rivers that make them more susceptible to earthquake induced hazards including liquefaction, lateral spreading, flooding, landslides and rock falls. The findings of this research are applicable to similar coastal and river environments elsewhere in the world where seismic hazards are also of significant concern. An interdisciplinary approach was used to document and analyse the coastal and river related effects of the Canterbury earthquake sequence on Christchurch city in order to derive transferable lessons that can be used to design less vulnerable urban communities and help to predict seismic vulnerabilities in other New Zealand and international urban coastal and river environments for the future. Methods used to document past and present features and earthquake impacts on coasts and rivers in Christchurch included using maps derived from Geographical Information Systems (GIS), photographs, analysis of interviews from coastal, river and engineering experts, and analysis of secondary data on seismicity, liquefaction potential, geology, and planning statutes. The Canterbury earthquake sequence had a significant effect on Christchurch, particularly around rivers and the coast. This was due to the susceptibility of rivers to lateral spreading and the susceptibility of the eastern Christchurch and estuarine environments to liquefaction. The collapse of river banks and the extensive cracking, tilting and subsidence that accompanied liquefaction, lateral spreading and rock falls caused damage to homes, roads, bridges and lifelines. This consequently blocked transportation routes, interrupted electricity and water lines, and damaged structures built in their path. This study found that there are a number of physical features of coastal and river environments from the past and the present that have induced vulnerabilities to earthquake hazards. The types of sediments found beneath eastern Christchurch are unconsolidated fine sands, silts, peats and gravels. Together with the high water tables located beneath the city, these deposits made the area particularly susceptible to liquefaction and liquefaction-induced lateral spreading, when an earthquake of sufficient size shook the ground. It was both past and present coastal and river processes that deposited the types of sediments that are easily liquefied during an earthquake. Eastern Christchurch was once a coastal and marine environment 6000 years ago when the shoreline reached about 6 km inland of its present day location, which deposited fine sand and silts over this area. The region was also exposed to large braided rivers and smaller spring fed rivers, both of which have laid down further fine sediments over the following thousands of years. A significant finding of this study is the recognition that the Canterbury earthquake sequence has exacerbated existing coastal and river hazards and that assessments and monitoring of these changes will be an important component of Christchurch’s future resilience to natural hazards. In addition, patterns of recovery following the Canterbury earthquakes are highlighted to show that coasts and rivers are again vulnerable to earthquakes through their ability to recovery. This city’s capacity to incorporate resilience into the recovery efforts is also highlighted in this study. Coastal and river areas have underlying physical characteristics that make them increasingly vulnerable to the effects of earthquake hazards, which have not typically been perceived as a ‘coastal’ or ‘river’ hazard. These findings enhance scientific and management understanding of the effects that earthquakes can have on coastal and river environments, an area of research that has had modest consideration to date. This understanding is important from a coastal and river hazard management perspective as concerns for increased human development around coastlines and river margins, with a high seismic risk, continue to grow.
Natural disasters are increasingly disruptive events that affect livelihoods, organisations, and economies worldwide. Research has identified the impacts and responses of organisations to different types of natural disasters, and have outlined factors, such as industry sector, that are important to organisational vulnerability and resilience. One of the most costly types of natural disasters in recent years has been earthquakes, and yet to date, the majority of studies have focussed on the effects of earthquakes in urban areas, while rural organisational impact studies have primarily focused on the effects of meteorological and climatic driven hazards. As a result, the likely impacts of an earthquake on rural organisations in a developed context is unconstrained in the literature. In countries like New Zealand, which have major earthquakes and agricultural sectors that are significant contributors to the economy, it is important to know what impacts an earthquake event would have on the rural industries, and how these impacts compare to that of a more commonly analysed, high-frequency event. In September of 2010, rural organisations in Canterbury experienced the 4 September 2010 Mw 7.1 `Darfield' earthquake and the associated aftershocks, which came to be known as the Canterbury earth- quake sequence. The earthquake sequence caused intense ground shaking, creating widespread critical service outages, structural and non-structural damage to built infrastructure, as well as ground surface damage from ooding, liquefaction and surface rupture. Concurrently on September 18 2010, rural organisations in Southland experienced an unseasonably late snowstorm and cold weather snap that brought prolonged sub-zero temperatures, high winds and freezing rain, damaging structures in the City of Invercargill and causing widespread livestock losses and production decreases across the region. This thesis documents the effects of the Canterbury earthquake sequence and Southland snowstorm on farming and rural non-farming organisations, utilizing comparable methodologies to analyse rural organisational impacts, responses and recovery strategies to natural disasters. From the results, a short- term impact assessment methodology is developed for multiple disasters. Additionally, a regional asset repair cost estimation model is proposed for farming organisations following a major earthquake event, and the use of social capital in rural organisational recovery strategies following natural disasters is analysed.
Disaster recovery is significantly affected by funding availability. The timeliness and quality of recovery activities are not only impacted by the extent of the funding but also the mechanisms with which funding is prioritised, allocated and delivered. This research addresses the impact of funding mechanisms on the effectiveness and efficiency of post-disaster demolition and debris management programmes. A qualitative assessment of the impacts on recovery of different funding sources and mechanisms was carried out, using the 2010 Canterbury Earthquake as well as other recent international events as case studies. The impacts assessed include: timeliness, completeness, environmental, economic and social impacts. Of the case studies investigated, the Canterbury Earthquake was the only disaster response to rely solely on a privatised approach to insurance for debris management. Due to the low level of resident displacement and low level of hazard in the waste, this was a satisfactory approach, though not ideal. This approach has led to greater organisational complexity and delays. For many other events, the potential community wide impacts caused by the prolonged presence of disaster debris means that publicly funded and centrally facilitated programmes appear to be the most common and effective method of managing disaster waste.
The devastating magnitude M6.3 earthquake, that struck the city of Christchurch at 12:51pm on Tuesday 22 February 2011, caused widespread damage to the lifeline systems. Following the event, the Natural Hazard Research Platform (NHRP) of New Zealand funded a short-term project “Recovery of Lifelines” aiming to: 1) coordinate the provision of information to meet lifeline short-term needs; and to 2) facilitate the accessibility to lifelines of best practice engineering details, along with hazards and vulnerability information already available from the local and international scientific community. This paper aims to briefly summarise the management of the recovery process for the most affected lifelines systems, including the electric system, the road, gas, and the water and wastewater networks. Further than this, the paper intends to discuss successes and issues encountered by the “Recovery of Lifelines” NHRP project in supporting lifelines utilities.
The Canterbury earthquake sequence (2010-2011) was the most devastating catastrophe in New Zealand‘s modern history. Fortunately, in 2011 New Zealand had a high insurance penetration ratio, with more than 95% of residences being insured for these earthquakes. This dissertation sheds light on the functions of disaster insurance schemes and their role in economic recovery post-earthquakes. The first chapter describes the demand and supply for earthquake insurance and provides insights about different public-private partnership earthquake insurance schemes around the world. In the second chapter, we concentrate on three public earthquake insurance schemes in California, Japan, and New Zealand. The chapter examines what would have been the outcome had the system of insurance in Christchurch been different in the aftermath of the Canterbury earthquake sequence (CES). We focus on the California Earthquake Authority insurance program, and the Japanese Earthquake Reinsurance scheme. Overall, the aggregate cost of the earthquake to the New Zealand public insurer (the Earthquake Commission) was USD 6.2 billion. If a similar-sized disaster event had occurred in Japan and California, homeowners would have received only around USD 1.6 billion and USD 0.7 billion from the Japanese and Californian schemes, respectively. We further describe the spatial and distributive aspects of these scenarios and discuss some of the policy questions that emerge from this comparison. The third chapter measures the longer-term effect of the CES on the local economy, using night-time light intensity measured from space, and focus on the role of insurance payments for damaged residential property during the local recovery process. Uniquely for this event, more than 95% of residential housing units were covered by insurance and almost all incurred some damage. However, insurance payments were staggered over 5 years, enabling us to identify their local impact. We find that night-time luminosity can capture the process of recovery; and that insurance payments contributed significantly to the process of local economic recovery after the earthquake. Yet, delayed payments were less affective in assisting recovery and cash settlement of claims were more effective than insurance-managed repairs. After the Christchurch earthquakes, the government declared about 8000 houses as Red Zoned, prohibiting further developments in these properties, and offering the owners to buy them out. The government provided two options for owners: the first was full payment for both land and dwelling at the 2007 property evaluation, the second was payment for land, and the rest to be paid by the owner‘s insurance. Most people chose the second option. Using data from LINZ combined with data from Stats NZ, the fourth chapter empirically investigates what led people to choose this second option, and how peer effect influenced the homeowners‘ choices. Due to climate change, public disclosure of coastal hazard information through maps and property reports have been used more frequently by local government. This is expected to raise awareness about disaster risks in local community and help potential property owners to make informed locational decision. However, media outlets and business sector argue that public hazard disclosure will cause a negative effect on property value. Despite this opposition, some district councils in New Zealand have attempted to implement improved disclosure. Kapiti Coast district in the Wellington region serves as a case study for this research. In the fifth chapter, we utilize the residential property sale data and coastal hazard maps from the local district council. This study employs a difference-in-difference hedonic property price approach to examine the effect of hazard disclosure on coastal property values. We also apply spatial hedonic regression methods, controlling for coastal amenities, as our robustness check. Our findings suggest that hazard designation has a statistically and economically insignificant impact on property values. Overall, the risk perception about coastal hazards should be more emphasized in communities.
Depending on their nature and severity, disasters can create large volumes of debris and waste. Waste volumes from a single event can be the equivalent of many times the annual waste generation rate of the affected community. These volumes can overwhelm existing solid waste management facilities and personnel. Mismanagement of disaster waste can affect both the response and long term recovery of a disaster affected area. Previous research into disaster waste management has been either context specific or event specific, making it difficult to transfer lessons from one disaster event to another. The aim of this research is to develop a systems understanding of disaster waste management and in turn develop context- and disaster-transferrable decision-making guidance for emergency and waste managers. To research this complex and multi-disciplinary problem, a multi-hazard, multi-context, multi-case study approach was adopted. The research focussed on five major disaster events: 2011 Christchurch earthquake, 2009 Victorian Bushfires, 2009 Samoan tsunami, 2009 L’Aquila earthquake and 2005 Hurricane Katrina. The first stage of the analysis involved the development of a set of ‘disaster & disaster waste’ impact indicators. The indicators demonstrate a method by which disaster managers, planners and researchers can simplify the very large spectra of possible disaster impacts, into some key decision-drivers which will likely influence post-disaster management requirements. The second stage of the research was to develop a set of criteria to represent the desirable environmental, economic, social and recovery effects of a successful disaster waste management system. These criteria were used to assess the effectiveness of the disaster waste management approaches for the case studies. The third stage of the research was the cross-case analysis. Six main elements of disaster waste management systems were identified and analysed. These were: strategic management, funding mechanisms, operational management, environmental and human health risk management, and legislation and regulation. Within each of these system elements, key decision-making guidance (linked to the ‘disaster & disaster waste’ indicators) and management principles were developed. The ‘disaster & disaster waste’ impact indicators, the effects assessment criteria and management principles have all been developed so that they can be practically applied to disaster waste management planning and response in the future.
The Kaikoura earthquake in November 2016 highlighted the vulnerability of New Zealand’s rural communities to locally-specific hazard events, which generate regional and national scale impacts. Kaikoura was isolated with significant damage to both the east coast road (SH1) and rail corridor, and the Inland Road (Route 70). Sea bed uplift along the coast was significant – affecting marine resources and ocean access for marine operators engaged in tourism and harvesting, and recreational users. While communities closest to the earthquake epicentre (e.g., Kaikoura, Waiau, Rotherham and Cheviot) suffered the most immediate earthquake damage, the damage to the transport network, and the establishment of an alternative transport route between Christchurch and Picton, has significantly impacted on more distant communities (e.g., Murchison, St Arnaud and Blenheim). There was also considerable damage to vineyard infrastructure across the Marlborough region and damage to buildings and infrastructure in rural settlements in Southern Marlborough (e.g., Ward and Seddon).
Research Report No.2010-03Ground motion prediction equations (GMPEs) for geometric-mean pseudo-spectral acceleration amplitudes from New Zealand (NZ) earthquakes are developed. A database of 2437 three-component ground motion records is developed by applying stringent quality criteria to the historically recorded events in NZ. Despite the large number of records, the database is deficient in empirical records from large magnitude events recorded at close distances to the fault rupture plane. As a result, the basis for the NZ-specific GMPE development is to examine the applicability of foreign GMPEs for similar tectonic regions and then modify the most applicable GMPEs based on both theoretical and statistically significant empirically-driven arguments. For active shallow crustal events, five different GMPEs are considered. It was found that the McVerry et al. (2006) model, which is the current model upon which seismic design guidelines and site-specific seismic hazard analyses in NZ are based, provided the worst fit to the NZ database, and that the Chiou et al. (2010) (C10) modification of the Chiou and Youngs (2008) model was the most applicable. Discrepancies between the C10 model and the NZ database that were empirically identified and theoretically justified were used to modify the C10 model for: (i) small magnitude scaling; (ii) scaling of short period ground motion from normal faulting events in volcanic crust; (iii) scaling of ground motions on very hard rock sites; (iv) anelastic attenuation in the NZ crust; and (v) consideration of the increased anelastic attenuation in the Taupo Volcanic Zone (TVZ). For subduction slab events, initially three models were considered. It was found that all of the models had some significant biases with respect to applicability for NZ. The Zhao et al. (2006) (Z06) model was selected because of the rigorous database upon which it was developed and modified by: (i) NZ-specific scaling at small magnitudes; (ii) path scaling at large distances; (iii) consideration of the increased TVZ attenuation; and (iv) revision of the standard deviation model. Based on these modifications the developed model showed no bias of the inter- and intra-event residuals as a function of various predictor variables. The standard deviation of the residuals using the revised standard deviation model also indicated that the model has an adequate precision. Three GMPEs were considered for subduction interface events. The Zhao et al. (2006) (Z06) model was the best performing model with only bias exhibited in the site response model, and possible over-prediction of large magnitude events. The Z06 interface model was modified to account for site response and magnitude scaling using the same functional forms as those of the developed active shallow crustal and subduction slab models. The developed model showed no bias of the inter- and intra-event residuals as a function of various predictor variables. The developed GMPEs include specific features as evident in the NZ database; consistent scaling for parameters not well constrained by the NZ database; and pseudo-spectral amplitudes for vibration periods from 0.01 to 10 seconds. Hence, these models represent a significant advance in the state-of-the art for empirical ground motion prediction in NZ.
Research undertaken and literature reviewed show that major natural disasters present considerable risk to Governors Bay. Earthquakes, and resulting secondary hazards from natural disasters, could lead to the isolation of the Governors Bay community for an extended period. In particular, the rupture of the Alpine Fault and the resulting mega-quake could leave Governors Bay isolated for well over three weeks. Weaknesses in existing infrastructure in Governors Bay further places residents at risk. Therefore, it is essential that residents are prepared for a period of extended isolation, with little to no access to clean water, power, internet and cellular coverage. Ultimately, community preparedness will be the key to maintaining social cohesion and saving lives during an emergency event. The community hub in Governors Bay establishes a pre-determined locale for community co-ordination, collection, and distribution of supplies as well as a functional place to go when all else fails.
Novel Gel-push sampling was employed to obtain high quality samples of Christchurch sands from the Central Business District, at sites where liquefaction was observed in 22 February 2011, and 13 June 2011 earthquakes. The results of cyclic triaxial testing on selected undisturbed specimens of typical Christchurch sands are presented and compared to empirical procedures used by practitioners. This comparison suggests cyclic triaxial data may be conservative, and the Magnitude Scaling Factor used in empirical procedures may be unconservative for highly compressible soils during near source moderate to low magnitude events. Comparison to empirical triggering curves suggests the empirical method generally estimates the cyclic strength of Christchurch sands within a reasonable degree of accuracy as a screening evaluation tool for liquefaction hazard, however for sands with moderate to high fines content it may be significantly unconservative, highlighting the need for high quality sampling and testing on important projects where seismic performance is critical.
