The timing of large Holocene prehistoric earthquakes is determined by dated surface ruptures and landslides at the edge of the Australia-Pacific plate boundary zone in North Canterbury, New Zealand. Collectively, these data indicate two large (M > 7) earthquakes during the last circa 2500 years, within a newly formed zone of hybrid strike-slip and thrust faulting herein described as the Porter's Pass-to-Amberley Fault Zone (PPAFZ). Two earlier events during the Holocene are also recognized, but the data prior to 2500 years are presumed to be incomplete. A return period of 1300–2000 years between large earthquakes in the PPAFZ is consistent with a late Holocene slip rate of 3–4 mm/yr if each displacement is in the range 4–8 m. Historical seismicity in the PPAFZ is characterized by frequent small and moderate magnitude earthquakes and a seismicity rate that is identical to a region surrounding the structurally mature Hope fault of the Marlborough Fault System farther north. This is despite an order-of-magnitude difference in slip rate between the respective fault zones and considerable differences in the recurrence rate of large earthquakes. The magnitude-frequency distribution in the Hope fault region is in accord with the characteristic earthquake model, whereas the rate of large earthquakes in the PPAFZ is approximated (but over predicted) by the Gutenberg-Richter model. The comparison of these two fault zones demonstrates the importance of the structural maturity of the fault zone in relation to seismicity rates inferred from recent, historical, and paleoseismic data.
The impact of the Canterbury earthquake sequence of 2010-12 and its aftermath has been enormous. This inventory lists some of the thousands of community-led groups and initiatives across the region that have developed or evolved as a result of the quake. This inventory is the third such inventory to have been produced. The Christchurch Earthquake Activity Inventory was released by Landcare Research in May 2011, three months after the devastating 22 February 2011 earthquake. The second inventory, entitled An Inventory of Community-led Recovery Initiatives in Canterbury, was collated by Bailey Peryman and Dr Suzanne Vallance (Lincoln University) approximately one year after the February earthquake. The research for this third inventory was undertaken over a four month period from June to September 2013, and was conducted primarily through online searches.
On 4 September 2010, a 7.1 magnitude earthquake struck near Darfield, 40 kilometres west of Christchurch, New Zealand. The quake caused significant damage to land and buildings nearby, with damage extending to Christchurch city. On 22 February 2011, a 6.3 magnitude earthquake struck Christchurch, causing extensive and significant damage across the city and with the loss of 185 lives. Years on from these events, occasional large aftershocks continue to shake the region. Two main entomological collections were situated within close proximity to the 2010/11 Canterbury earthquakes. The Lincoln University Entomology Research Collection, which is housed on the 5th floor of a 7 storey building, was 27.5 km from the 2010 Darfield earthquake epicentre. The Canterbury Museum Entomology Collection, which is housed in the basement of a multi-storeyed heritage building, was 10 km from the 2011 Christchurch earthquake epicentre. We discuss the impacts of the earthquakes on these collections, the causes of the damage to the specimens and facilities, and subsequent efforts that were made to prevent further damage in the event of future seismic events. We also discuss the wider need for preparedness against the risks posed by natural disasters and other catastrophic events.
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).
On September the 4th 2010 and February 22nd 2011 the Canterbury region of New Zealand was shaken by two massive earthquakes. This paper is set broadly within the civil defence and emergency management literature and informed by recent work on community participation and social capital in the building of resilient cities. Work in this area indicates a need to recognise both the formal institutional response to the earthquakes as well as the substantive role communities play in their own recovery. The range of factors that facilitate or hinder community involvement also needs to be better understood. This paper interrogates the assumption that recovery agencies and officials are both willing and able to engage communities who are themselves willing and able to be engaged in accordance with recovery best practice. Case studies of three community groups – CanCERN, Greening the Rubble and Gap Filler – illustrate some of the difficulties associated with becoming a community during the disaster recovery phase. Based on my own observations and experiences, combined with data from approximately 50 in-depth interviews with Christchurch residents and representatives from community groups, the Christchurch City Council, the Earthquake Commission and so on, this paper outlines some practical strategies emerging communities may use in the early disaster recovery phase that then strengthens their ability to ‘participate’ in the recovery process.
Liquefaction affects late Holocene, loose packed and water saturated sediment subjected to cyclical shear stress. Liquefaction features in the geological record are important off-fault markers that inform about the occurrence of moderate to large earthquakes (> 5 Mw). The study of contemporary liquefaction features provides a better understanding of where to find past (paleo) liquefaction features, which, if identified and dated, can provide information on the occurrence, magnitude and timing of past earthquakes. This is particularly important in areas with blind active faults. The extensive liquefaction caused by the 2010-2011 Canterbury Earthquake Sequence (CES) gave the geoscience community the opportunity to study the liquefaction process in different settings (alluvial, coastal and estuarine), investigating different aspects (e.g. geospatial correlation with landforms, thresholds for peak ground acceleration, resilience of infrastructures), and to collect a wealth geospatial dataset in the broad region of the Canterbury Plains. The research presented in this dissertation examines the sedimentary architecture of two environments, the alluvial and coastal settings, affected by liquefaction during the CES. The novel aim of this study is to investigate how landform and subsurface sedimentary architecture influence liquefaction and its surface manifestation, to provide knowledge for locating studies of paleoliquefaction in future. Two study cases documented in the alluvial setting showed that liquefaction features affected a crevasse splay and point bar ridges. However, the liquefaction source layer was linked to paleochannel floor deposits below the crevasse splay in the first case, and to the point bar deposits themselves in the second case. This research documents liquefaction features in the coastal dune system of the Canterbury Plains in detail for the first time. In the coastal dune setting the liquefiable layer is near the surface. The pore water pressure is vented easily because the coastal dune soil profile is entirely composed of non-cohesive, very well sorted sandy sediment that weakly resists disturbance from fluidised sediment under pressure. As a consequence, the liquefied flow does not need to find a specific crack through which the sediment is vented at the surface; instead, the liquefied sand finds many closely spaced conduits to vent its excess of pore water pressure. Therefore, in the coastal dune setting it is rare to observe discrete dikes (as they are defined in the alluvial setting), instead A horizon delamination (splitting) and blistering (near surface sills) are more common. The differences in styles of surface venting lead to contrasts in patterns of ejecta in the two environments. Whereas the alluvial environment is characterised by coalesced sand blows forming lineations, the coastal dune environment hosts apparently randomly distributed isolated sand blows often associated with collapse features. Amongst the techniques tested for the first time to investigate liquefaction features are: 3D GPR, which improved the accuracy of the trenching even six years after the liquefaction events; thin section analysis to investigate sediment fabric, which helped to discriminate liquefied sediment from its host sediment, and modern from paleoliquefaction features; a Random Forest classification based on the CES liquefaction map, which was used to test relationships between surface manifestation of liquefaction and topographic parameters. The results from this research will be used to target new study sites for future paleoliquefaction research and thus will improve the earthquake hazard assessment across New Zealand.
The Canterbury region of New Zealand was shaken by major earthquakes on the 4th September 2010 and 22nd February 2011. The quakes caused 185 fatalities and extensive land, infrastructure and building damage, particularly in the Eastern suburbs of Christchurch city. Almost 450 ha of residential and public land was designated as a ‘Red Zone’ unsuitable for residential redevelopment because land damage was so significant, engineering solutions were uncertain, and repairs would be protracted. Subsequent demolition of all housing and infrastructure in the area has left a blank canvas of land stretching along the Avon River corridor from the CBD to the sea. Initially the Government’s official – but enormously controversial – position was that this land would be cleared and lie fallow until engineering solutions could be found that enabled residential redevelopment. This paper presents an application of a choice experiment (CE) that identified and assessed Christchurch residents’ preferences for different land use options of this Red Zone. Results demonstrated strong public support for the development of a recreational reserve comprising a unique natural environment with native fauna and flora, healthy wetlands and rivers, and recreational opportunities that align with this vision. By highlighting the value of a range of alternatives, the CE provided a platform for public participation and expanded the conversational terrain upon which redevelopment policy took place. We conclude the method has value for land use decision-making beyond the disaster recovery context.
The Canterbury earthquakes that happened in 2010 and 2011 have attracted many migrant workers to the region to assist with the rebuilding effort. However, research on the impact of influx of migrants on the labour market outcomes of a local industry post-disaster is limited internationally and locally. The main objective of this study is to examine the impact of the Canterbury earthquakes on the changes in demographic composition and occupational structure for the local and foreign workers in the Greater Christchurch construction industry. Replicating the discrete dependent variable regression methods used in the study by Sisk and Bankston III (2014), this study also aimed to compare their findings on the impact of the influx of migrants on the New Orleans construction industry with outcomes in Greater Christchurch. Customised data from New Zealand Censuses 2006 and 2013 were used to represent the pre- and post-earthquake periods. This study found that the rebuild has provided opportunities for migrant workers to enter the Greater Christchurch construction industry. The increased presence of migrant construction workers did not displace the locals. In fact, the likelihoods for both locals’ and migrants’ participation in the industry improved post-earthquakes. The earthquakes also increased overall workers’ participation at the lowest end of the occupational structure. However, the earthquakes created few significant changes to the distribution of local and migrant workers at the various occupational levels in the industry. Local workers still dominated all occupational levels post-earthquakes. The aggregated education levels of the construction workers were higher post-earthquakes, particularly among the migrant workers. Overall, migrant workers in the Greater Christchurch construction industry were more diverse, more educated and participated in higher occupational levels than migrants assisting in the New Orleans rebuild, due possibly to differences in immigration policies between New Zealand and the United States of America.
This research provides an investigation into the impact on the North Island freight infrastructure, in the event of a disruption of the Ports of Auckland (POAL). This research is important to New Zealand, especially having experienced the Canterbury earthquake disaster in 2010/2011 and the current 2012 industrial action plaguing the POAL. New Zealand is a net exporter of a combination of manufactured high value goods, commodity products and raw materials. New Zealand’s main challenge lies in the fact of its geographical distances to major markets. Currently New Zealand handles approximately 2 million containers per annum, with a minimum of ~40% of those containers being shipped through POAL. It needs to be highlighted that POAL is classified as an import port in comparison to Port of Tauranga (POT) that has traditionally had an export focus. This last fact is of great importance, as in a case of a disruption of the POAL, any import consigned to the Auckland and northern region will need to be redirected through POT in a quick and efficient way to reach Auckland and the northern regions. This may mean a major impact on existing infrastructure and supply chain systems that are currently in place. This study is critical as an element of risk management, looking at how to mitigate the risk to the greater Auckland region. With the new Super City taking hold, the POAL is a fundamental link in the supply chain to the largest metropolitan area within New Zealand.
Study region: Christchurch, New Zealand. Study focus: Low-lying coastal cities worldwide are vulnerable to shallow groundwater salinization caused by saltwater intrusion and anthropogenic activities. Shallow groundwater salinization can have cascading negative impacts on municipal assets, but this is rarely considered compared to impacts of salinization on water supply. Here, shallow groundwater salinity was sampled at high spatial resolution (1.3 piezometer/km²), then mapped and spatially interpolated. This was possible due to a uniquely extensive set of shallow piezometers installed in response to the 2010–11 Canterbury Earthquake Sequence to assess liquefaction risk. The municipal assets located within the brackish groundwater areas were highlighted. New hydrological insights for the region: Brackish groundwater areas were centred on a spit of coastal sand dunes and inside the meander of a tidal river with poorly drained soils. The municipal assets located within these areas include: (i) wastewater and stormwater pipes constructed from steel-reinforced concrete, which, if damaged, are vulnerable to premature failure when exposed to chloride underwater, and (ii) 41 parks and reserves totalling 236 ha, within which salt-intolerant groundwater-dependent species are at risk. This research highlights the importance of determining areas of saline shallow groundwater in low-lying coastal urban settings and the co-located municipal assets to allow the prioritisation of sites for future monitoring and management.
At 00:02 on 14 November, 2016 a destructive 7.8 Mw earthquake struck the North Canterbury region of New Zealand’s South Island. Prior to and following the earthquake, natural and social scientists conducted a significant amount of research on the resilience processes and recovery efforts in North Canterbury. This thesis examines community resilience in Kaikōura, a small town and district greatly impacted by the earthquake. Community resilience has been widely used in disaster risk reduction research, policy, and practice to describe how a group of individuals within a boundary respond to events, hazards, and shifts in their everyday life. Using exploratory inquiry, this thesis adopts qualitative research methods including document analysis, 24 semi-structured interviews, and participant observation to explore the idea that the recent scholarly emphasis on resilience has come at the expense of critical engagement with the complexities of communities. I draw on the idea of ‘collectives’ (comprising community-based organisations or less formal social networks with a shared purpose) as a lens to consider how, when unexpected life events happen, collectives can be regarded as a resource for change or constancy. The examination of collectives following a disaster can lend insight into the many elements of community as they bring people together in collaboration or drive them apart in conflict. This thesis therefore contributes to an enhanced practical and theoretical understanding of both community and resilience.
The city of Ōtautahi/Christchurch experienced a series of earthquakes that began on September 4th, 2010. The most damaging event occurred on February 22nd, 2011 but significant earthquakes also occurred on June 13th and December 23rd with aftershocks still occurring well into 2012. The resulting disaster is the second deadliest natural disaster in New Zealand’s history with 185 deaths. During 2011 the Canterbury earthquakes were one of the costliest disasters worldwide with an expected cost of up to $NZ30 billion. Hundreds of commercial buildings and thousands of houses have been destroyed or are to be demolished and extensive repairs are needed for infrastructure to over 100,000 homes. As many as 8,900 people simply abandoned their homes and left the city in the first few months after the February event (Newell, 2012), and as many as 50,000 may leave during 2012. In particular, young whānau and single young women comprised a disproportionate number of these migrants, with evidence of a general movement to the North Island. Te Puni Kōkiri sought a mix of quantitative and qualitative research to examine the social and economic impacts of the Christchurch earthquakes on Māori and their whānau. The result of this work will be a collection of evidence to inform policy to support and assist Māori and their whānau during the recovery/rebuild phases. To that end, this report triangulates available statistical and geographical information with qualitative data gathered over 2010 and 2011 by a series of interviews conducted with Māori who experienced the dramatic events associated with the earthquakes. A Māori research team at Lincoln University was commissioned to undertake the research as they were already engaged in transdisciplinary research (began in the May 2010), that focused on quickly gathering data from a range of Māori who experienced the disaster, including relevant economic, environmental, social and cultural factors in the response and recovery of Māori to these events. Participants for the qualitative research were drawn from Māori whānau who both stayed and left the city. Further data was available from ongoing projects and networks that the Lincoln research team was already involved in, including interviews with Māori first responders and managers operating in the CBD on the day of the February event. Some limited data is also available from younger members of affected whānau. Māori in Ōtautahi/Christchurch City have exhibited their own culturally-attuned collective responses to the disaster. However, it is difficult to ascertain Māori demographic changes due to a lack of robust statistical frameworks but Māori outward migration from the city is estimated to range between 560 and 1,100 people. The mobility displayed by Māori demonstrates an important but unquantified response by whānau to this disaster, with emigration to Australia presenting an attractive option for young Māori, an entrenched phenomenon that correlates to cyclical downturns and the long-term decline of the New Zealand economy. It is estimated that at least 315 Māori have emigrated from the Canterbury region to Australia post-quake, although the disaster itself may be only one of a series of events that has prompted such a decision. Māori children made up more than one in four of the net loss of children aged 6 to 15 years enrolled in schools in Greater Christchurch over the year to June 2011. Research literature identifies depression affecting a small but significant number of children one to two years post-disaster and points to increasing clinical and organisational demands for Māori and other residents of the city. For those residents in the eastern or coastal suburbs – home to many of the city’s Māori population - severe damage to housing, schools, shops, infrastructure, and streets has meant disruption to their lives, children’s schooling, employment, and community functioning. Ongoing abandonment of homes by many has meant a growing sense of unease and loss of security, exacerbated by arson, burglaries, increased drinking, a stalled local and national economy, and general confusion about the city’s future. Māori cultural resilience has enabled a considerable network of people, institutions, and resources being available to Māori , most noticeably through marae and their integral roles of housing, as a coordinating hub, and their arguing for the wider affected communities of Christchurch. Relevant disaster responses need to be discussed within whānau, kōhanga, kura, businesses, communities, and wider neighbourhoods. Comprehensive disaster management plans need to be drafted for all iwi in collaboration with central government, regional, and city or town councils. Overall, Māori are remarkably philosophical about the effects of the disaster, with many proudly relishing their roles in what is clearly a historic event of great significance to the city and country. Most believe that ‘being Māori’ has helped cope with the disaster, although for some this draws on a collective history of poverty and marginalisation, features that contribute to the vulnerability of Māori to such events. While the recovery and rebuild phases offer considerable options for Māori and iwi, with Ngāi Tahu set to play an important stakeholder in infrastructural, residential, and commercial developments, some risk and considerable unknowns are evident. Considerable numbers of Māori may migrate into the Canterbury region for employment in the rebuild, and trades training strategies have already been established. With many iwi now increasingly investing in property, the risks from significant earthquakes are now more transparent, not least to insurers and the reinsurance sector. Iwi authorities need to be appraised of insurance issues and ensure sufficient coverage exists and investments and developments are undertaken with a clear understanding of the risks from natural hazards and exposure to future disasters.
