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Images for Christchurch Earthquake 4 September 2010; more images...

Images, Alexander Turnbull Library

Two huge wrestlers, one representing 'Port Hills fault' and the other 'Greendale fault' struggle together over a broken Christchurch. Another wrestler, representing 'Other faults' appears in the distance yelling 'Is it my turn yet?' Context - Christchurch has now had three major earthquakes and thousands of aftershocks. It now appears likely that the Christchurch quakes resulted from activity on a fault extending directly eastward from the Alpine fault that remained unknown until last year, says Roger Musson, a seismologist at the British Geological Survey in Edinburgh. The new fault first came to light last September (4th) when a stronger but less calamitous quake shook Darfield, 40 kilometres west of Christchurch. Musson says the latest quake (Feb 22, 2011) probably resulted from an eastward continuation of activity on the same fault. "It has probably not moved for tens of thousands of years, so lots of strain built up," says Musson. The third major quake happened on 13th June 2011. (New Scientist - February 22, 2011) Quantity: 1 digital cartoon(s).

Images, Alexander Turnbull Library

Text across the top of the cartoon reads 'always design in context' There is a globe, small in the context, with a little message reading 'you are here' pointing, perhaps, to New Zealand or even more specifically, Christchurch; the globe is being threatened from all sides by forces of nature represented by the hand of god reaching out of clouds. Context - the Christchurch earthquakes of 4 September 2010 and 22 February 2011 and the idea that buildings must be designed in the context of their environment - NZ being earthquake-prone. Perhaps also the idea of 'design in context' in a broader sense. Quantity: 1 digital cartoon(s).

Images, Alexander Turnbull Library

At top left is text reading 'Christchurch pupils return to school...' The teacher has written the words 'Nosey', 'Bob', and 'Double' on the blackboard and says to the children 'Our first test today... Sort these into Parkers we love and Parkers we don't'... Context - the correct answers would be that we hate 'nosey parkers' and 'double parkers' but that we love 'Bob Parker'. Bob Parker is the Mayor of Christchurch and is generally considered to have done a remarkably good job of demonstrating calm and cheerfulness after the two earthquakes of 4 September 2010 and 22 February 2011, as well as having been able to chose fitting words to express grief and despair at so much loss. Quantity: 1 digital cartoon(s).

Images, Alexander Turnbull Library

A man, half shown, sits on a loo and says 'Dang! I'm busting again! as he reaches for the toilet paper which has a different 'quake claim' printed on each section. Context - Magnitude 6.0 and 5.5 earthquakes rocked Christchurch again at 1pm and 2.20pm on 13th June 2011. These quakes follow the first earthquake on September 4th 2010 and the second on February 22nd 2011. (www.stuff.co.nz, 13 June 2011) Each time there is a significant quake more damage is done and so people have to make further insurance claims. Quantity: 1 digital cartoon(s).

Research papers, University of Canterbury Library

At 4.35am on Saturday 4 September 2010, a magnitude 7.1 earthquake struck near the township of Darfield in Canterbury leading to widespread damage in Christchurch and the wider central Canterbury region. Though it was reported no lives were lost, that was not entirely correct. Over 3,000 animals perished as a result of the earthquake and 99% of these deaths would have been avoidable if appropriate mitigation measures had been in place. Deaths were predominantly due to zoological vulnerability of birds in captive production farms. Other problems included lack of provision of animal welfare at evacuation centres, issues associated with multiple lost and found pet services, evacuation failure due to pet separation and stress impact on dairy herds and associated milk production. The Canterbury Earthquake has highlighted concerns over a lack of animal emergency welfare planning and capacity in New Zealand, an issue that is being progressed by the National Animal Welfare Emergency Management Group. As animal emergency management becomes better understood by emergency management and veterinary professionals, it is more likely that both sectors will have greater demands placed upon them by national guidelines and community expectations to ensure provisions are made to afford protection of animals in times of disaster. A subsequent and more devastating earthquake struck the region on Monday 22 February 2011; this article however is primarily focused on the events pertaining to the September 4 event.

Images, Alexander Turnbull Library

Text at top left reads 'Don't forget rubbish day' The cartoon is a large wheelie bin stacked high with debris from 'old dunger buildings'. Someone in a damaged house nearby says 'Good riddance!' Context - Two earthquakes and hundreds of aftershocks have hit Christchurch, the first on 4 September 2010 and a second more devastating one on 22 February 2011. Earthquake Recovery Minister Gerry Brownlee may or may not have actually used the words 'old dungers' to describe some of Christchurch's heritage buildings that are not worth keeping but he might as well have done because many people believe that this is the way he thinks. Debate about which heritage buildings should be kept and which demolished has begun along with debate about how the city should be rebuilt. Quantity: 1 digital cartoon(s).

Images, Alexander Turnbull Library

A man representing 'EQC' (Earthquake Commission) talks to a couple outside their collapsed house. He says 'Unfortunately, this is a NORTH Canterbury collapse - so you'll only get your first $100,000 back.' Context: This refers both to the collapse of the South Canterbury Finance Company and to the problems that people are having with insurance companies in North Canterbury after the first Christchurch earthquake on September 4th 2010. Quantity: 1 digital cartoon(s).

Images, Alexander Turnbull Library

ACT leader Rodney Hide stands alone in the middle of a blasted plain that was once the 'Christchurch CBD' and says 'A level playing field, excellent. Now we can leave the rest to the market'. Context - Christchurch after the earthquakes of 4 September 2010 and 22 February 2011. ACT explicitly promotes a free market philosophy - a (literal) level playing field in the Christchurch CBD sounds like an excellent opportunity to test the powers of the free market. Quantity: 1 digital cartoon(s).

Images, Alexander Turnbull Library

As a man stands up to his knees in liquefaction as Christchurch rocks in another aftershock he reads a newspaper which has one headline reading 'More severe aftershocks in Christchurch' and a second headline that reads 'I have an unshakeable belief in New Zealanders says next Gov. Gen.'. Context - Two earthquakes and hundreds of aftershocks have hit Christchurch, the first on 4 September 2010 and a second more devastating one on 22 February 2011. The new Governor General is Lieutenant General Jerry Mateparae; he takes over the role from incumbent Sir Anand Satyanand in August 2011. Quantity: 1 digital cartoon(s).

Images, Alexander Turnbull Library

The cartoon consists of the words 'More quACHES' drawn with a stencil. Context - Two more earthquakes rocked Christchurch on 13th June, following those of 4 September 2010 and 22 February 2011. The first magnitude 5.5 quake struck at 1pm, 10 kilometres east of Christchurch at Taylor's Mistake beach, at a depth of 11 kilometres, and sent people scrambling for cover. It was followed at 2.20pm by a more powerful magnitude 6 quake, centred 10 kilometres southeast of the city and 9km underground. There is a wordplay on 'quakes' and 'aches'. Quantity: 1 digital cartoon(s).

Research papers, University of Canterbury Library

The 2010–2011 Canterbury earthquake sequence began with the 4 September 2010, Mw7.1 Darfield earthquake and includes up to ten events that induced liquefaction. Most notably, widespread liquefaction was induced by the Darfield and Mw6.2 Christchurch earthquakes. The combination of well-documented liquefaction response during multiple events, densely recorded ground motions for the events, and detailed subsurface characterization provides an unprecedented opportunity to add well-documented case histories to the liquefaction database. This paper presents and applies 50 high-quality cone penetration test (CPT) liquefaction case histories to evaluate three commonly used, deterministic, CPT-based simplified liquefaction evaluation procedures. While all the procedures predicted the majority of the cases correctly, the procedure proposed by Idriss and Boulanger (2008) results in the lowest error index for the case histories analyzed, thus indicating better predictions of the observed liquefaction response.

Images, Alexander Turnbull Library

The cartoon shows the Christchurch Anglican Cathedral tower in ruins and without its steeple. Above the drawing is the date '22.2.11'. A second version shows a huge magnitude 6.3 earthquake tremor on a seismic graph on top of which is the date '22.2.11'. Context - On 22 February 2011 at 12:51 pm (NZDT), Christchurch experienced a major magnitude 6.3 earthquake, which resulted in severe damage and many casualties. A National State of Emergency has been declared. The cathedral tower has collapsed and there has been devastating damage to the remaining structure. The Cathedral is one of around six sites of extreme concern around the city where many are believed to still be trapped. This earthquake followed on from an original magnitude 7.1 earthquake on 4 September 2010 which did far less damage and in which no-one died. Two versions of this cartoon are available Quantity: 2 digital cartoon(s).

Research papers, University of Canterbury Library

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).

Images, Alexander Turnbull Library

Text above reads 'Prince William comes to Christchurch...' A special royal portaloo has been arranged for the visit of Prince William to Christchurch; it is built to resemble a castle and has gold door fittings. On either side of the portaloo stands a sentry guard. The prince who is inside whispers 'I can't find the royal flush button' (wordplay on 'royal flush' and the 'flush' of a toilet) Context - Prince William visited the Civil Defence headquarters in Christchurch with Earthquake Recovery Minister Gerry Brownlee and Christchurch Mayor Bob Parker on the 17th March to see the damage caused by the earthquakes of the 4th September 2010 and the 22 February 2011. Quantity: 1 digital cartoon(s).

Images, Alexander Turnbull Library

In the first seven of eight frames astrologer Ken Moon predicts a 'black day ahead', a 'day of great shaking' and 'terror' and 'children crying' and 'people fleeing' and 'a day in May'. In the last frame people realize that he has seen, not an earthquake, but the budget. Context - After the two big earthquakes in Christchurch on 4 September 2010 and 22 February 2011, the so-called Moon Man, Ken Ring, backed away from his prediction that Christchurch would be whacked by a huge earthquake on the 20th of March 2011. His claims terrified Cantabrians and led to people fleeing Christchurch. The 2011 budget will be announced in May and predictions are that it will be a cost-cutting one because of New Zealand's debt, partially caused by the Christchurch earthquakes. Quantity: 1 digital cartoon(s).

Images, Alexander Turnbull Library

The arms of a woman who represents New Zealand reach out to a baby to whom she has just given birth. The baby represents '2011' and is a particularly hideous specimen. The doctor who holds the baby says 'He's cute now but wait 'til he gets older!' Outside the window is seen a cracked and damaged landscape and a storm rages; the headstone of a grave reads 'RIP 2010'. Context - Christchurch or maybe the South Island have had a bad year because of the Pike River Mine disaster and the earthquake of 4 September 2010. There is perhaps prescience in this cartoon because on 22 February 2011 a much worse earthquake hit Christchurch. Published in The Press Quantity: 1 digital cartoon(s).

Research papers, University of Canterbury Library

In the period between September 2010 and December 2011, Christchurch was shaken by a series of strong earthquakes including the MW7.1 4 September 2010, Mw 6.2 22 February 2011, MW6.2 13 June 2011 and MW6.0 23 December 2011 earthquakes. These earthquakes produced very strong ground motions throughout the city and surrounding areas that resulted in soil liquefaction and lateral spreading causing substantial damage to buildings, infrastructure and the community. The stopbank network along the Kaiapoi and Avon River suffered extensive damage with repairs projected to take several years to complete. This presented an opportunity to undertake a case-study on a regional scale of the effects of liquefaction on a stopbank system. Ultimately, this information can be used to determine simple performance-based concepts that can be applied in practice to improve the resilience of river protection works. The research presented in this thesis draws from data collected following the 4th September 2010 and 22nd February 2011 earthquakes. The stopbank damage is categorised into seven key deformation modes that were interpreted from aerial photographs, consultant reports, damage photographs and site visits. Each deformation mode provides an assessment of the observed mechanism of failure behind liquefaction-induced stopbank damage and the factors that influence a particular style of deformation. The deformation modes have been used to create a severity classification for the whole stopbank system, being ‘no or low damage’ and ‘major or severe damage’, in order to discriminate the indicators and factors that contribute to ‘major to severe damage’ from the factors that contribute to all levels of damage a number of calculated, land damage, stopbank damage and geomorphological parameters were analysed and compared at 178 locations along the Kaiapoi and Avon River stopbank systems. A critical liquefiable layer was present at every location with relatively consistent geotechnical parameters (cone resistance (qc), soil behaviour type (Ic) and Factor of Safety (FoS)) across the study site. In 95% of the cases the critical layer occurred within two times the Height of the Free Face (HFF,). A statistical analysis of the geotechnical factors relating to the critical layer was undertaken in order to find correlations between specific deformation modes and geotechnical factors. It was found that each individual deformation mode involves a complex interplay of factors that are difficult to represent through correlative analysis. There was, however, sufficient data to derive the key factors that have affected the severity of deformation. It was concluded that stopbank damage is directly related to the presence of liquefaction in the ground materials beneath the stopbanks, but is not critical in determining the type or severity of damage, instead it is merely the triggering mechanism. Once liquefaction is triggered it is the gravity-induced deformation that causes the damage rather than the shaking duration. Lateral spreading and specifically the depositional setting was found to be the key aspect in determining the severity and type of deformation along the stopbank system. The presence or absence of abandoned or old river channels and point bar deposits was found to significantly influence the severity and type of deformation. A review of digital elevation models and old maps along the Kaiapoi River found that all of the ‘major to severe’ damage observed occurred within or directly adjacent to an abandoned river channel. Whilst a review of the geomorphology along the Avon River showed that every location within a point bar deposit suffered some form of damage, due to the depositional environment creating a deposit highly susceptible to liquefaction.

Images, Alexander Turnbull Library

Text top left reads 'A tale of two quakes' In the first frame a man runs from 'radiation leaks' yelling 'The end of the world!' and in the second frame a man runs from the notion 'No World Cup?' yelling 'The end of the world!' Context - the terrible earthquake and tsunami in Japan 11 March 2011 that have led to the overheating of several nuclear power plants that are leaking radiation and threaten a nuclear catastrophe and the Christchurch earthquakes of 4 September 2010 and 22 February 2011 that have led to the decision that because of the amount of damage to the venue plus infrastructures and accommodation for visitors the Rugby World Cup will not be played in Christchurch. Quantity: 1 digital cartoon(s).

Images, Alexander Turnbull Library

The cartoon shows God sitting at his computer with an image of a devastated Christchurch on the screen. He is about to hit the 'smite' key. Text above reads 'God at his computer'. Context - Two more earthquakes rocked Christchurch on 13th June, following those of 4 September 2010 and 22 February 2011. The first magnitude 5.5 quake struck at 1pm, 10 kilometres east of Christchurch at Taylor's Mistake beach, at a depth of 11 kilometres, and sent people scrambling for cover. It was followed at 2.20pm by a more powerful magnitude 6 quake, centred 10 kilometres southeast of the city and 9km underground. Quantity: 1 digital cartoon(s).

Research papers, University of Canterbury Library

During 2010 and 2011, major earthquakes caused widespread damage and the deaths of 185 people in the city of Christchurch. Damaged school buildings resulted in state intervention which required amendment of the Education Act of 1989, and the development of ‘site sharing agreements’ in undamaged schools to cater for the needs of students whose schools had closed. An effective plan was also developed for student assessment through establishing an earthquake impaired derived grade process. Previous research into traditional explanations of educational inequalities in the United Kingdom, the United States of America, and New Zealand were reviewed through various processes within three educational inputs: the student, the school and the state. Research into the impacts of urban natural disasters on education and education inequalities found literature on post disaster education systems but nothing could be found that included performance data. The impacts of the Canterbury earthquakes on educational inequalities and achievement were analysed over 2009-2012. The baseline year was 2009, the year before the first earthquake, while 2012 is seen as the recovery year as no schools closed due to seismic events and there was no state intervention into the education of the region. National Certificate of Educational Achievement (NCEA) results levels 1-3 from thirty-four secondary schools in the greater Christchurch region were graphed and analysed. Regression analysis indicates; in 2009, educational inequalities existed with a strong positive relationship between a school’s decile rating and NCEA achievement. When schools were grouped into decile rankings (1-10) and their 2010 NCEA levels 1-3 results were compared with the previous year, the percentage of change indicates an overall lower NCEA achievement in 2010 across all deciles, but particularly in lower decile schools. By contrast, when 2011 NCEA results were compared with those of 2009, as a percentage of change, lower decile schools fared better. Non site sharing schools also achieved higher results than site sharing schools. State interventions, had however contributed towards student’s achieving national examinations and entry to university in 2011. When NCEA results for 2012 were compared to 2009 educational inequalities still exist, however in 2012 the positive relationship between decile rating and achievement is marginally weaker than in 2009. Human ethics approval was required to survey one Christchurch secondary school community of students (aged between 12 and 18), teachers and staff, parents and caregivers during October 2011. Participation was voluntary and without incentives, 154 completed questionnaires were received. The Canterbury earthquakes and aftershocks changed the lives of the research participants. This school community was displaced to another school due to the Christchurch earthquake on 22 February 2011. Research results are grouped under four geographical perspectives; spatial impacts, socio-economic impacts, displacement, and health and wellbeing. Further research possibilities include researching the lag effects from the Canterbury earthquakes on school age children.

Audio, Radio New Zealand

Questions to Ministers 1. Hon ANNETTE KING to the Minister for Social Development and Employment: How many working-age people are currently receiving a main benefit and how does this compare to July 2010? 2. AMY ADAMS to the Minister of Finance: What reports has he received on the cost of damage from the Canterbury earthquake? 3. Hon DAVID CUNLIFFE to the Minister of Finance: Will he agree to a full public and independent Commission of Inquiry into the collapse of South Canterbury Finance? 4. METIRIA TUREI to the Attorney-General: Does he stand by his statement that the Marine and Coastal Area (Takutai Moana) Bill "treats all New Zealanders including Māori without discrimination"? 5. Hon DARREN HUGHES to the Minister of Transport: Does he stand by his statement that "the Government is totally committed to the SuperGold Card"? 6. TIM MACINDOE to the Minister for Social Development and Employment: What is the Government doing to support the Canterbury community through the earthquake recovery? 7. Hon TREVOR MALLARD to the Minister of Education: Does she stand by all of her statements in answer to oral question No. 8 yesterday? 8. Dr PAUL HUTCHISON to the Minister of Health: What reports has he received on the Canterbury District Health Board's actions following the Canterbury earthquake? 9. Hon DAVID PARKER to the Attorney-General: Given his answer yesterday that he agreed with the Prime Minister's statement earlier this year, "in the end if we can't reach an agreement then the status quo will remain", what acknowledgement, if any, has he received from the Māori Party that the new legal framework for settling foreshore and seabed claims will be "durable"? 10. Dr JACKIE BLUE to the Minister of Transport: What updates has he received on transport in and around Canterbury following the earthquake and numerous aftershocks? 11. DARIEN FENTON to the Minister of Labour: Is she currently considering any changes to employment law that were not included in the changes announced at the National Party Conference; if so, what are they? 12. KATRINA SHANKS to the Minister of Housing: How is the Department of Building and Housing working to keep landlords and tenants informed of their rights and responsibilities following the Christchurch earthquake?

Images, Alexander Turnbull Library

It is the middle of the night and a man wearing his dressing-gown runs out of his house towards a portaloo clutching a toilet roll and saying 'Try me'. The neighbourhood is wrecked by earthquakes. On the ground is a newspaper with a headline that reads 'New Delhi athletes substandard accomodation facilities'. A second newspaper reads 'Given the choice many prefer to stay home'. Context: The first Christchurch earthquake shook the city on early morning of the 4th September 2010. The destruction of sewage infrastructure has meant portaloos and long-drops have become de rigeur as a consequence. There was a desperate rush to get the village ready for the influx of athletes before the opening of the Commonwealth Games on 3rd October 2010 and there was a fear that unsatisfactory sanitation systems might cause health and safety problems. Quantity: 1 digital cartoon(s).

Images, Alexander Turnbull Library

The text 'Rugby World Cup' runs across the top of the cartoon. Below is a poster depicting the shape of a rugby ball with a double koru design and the year '2011'. It is accompanied by the words 'Rugby New Zealand (well not quite all New Zealand)' Someone off screen kicks a rugby ball that represents 'Christrch' across the frame. Context - Christchurch has been told that they will not be able to host any Rugby World Cup games because of the damage to the city after the earthquakes 4 September 2010 and 22 February 2011. Quantity: 1 digital cartoon(s).

Images, Alexander Turnbull Library

A man sits in an armchair in the ruins of his house with his wife beside him. A man carrying a briefcase marked 'EQC' has come to make an insurance assessment and says 'Unfortunately, this is a North Canterbury collapse - so you'll only get your first $100,000 back'. Context; the Christchurch earthquake of 4th September and the collapse of the South Canterbury Finance Company. Quantity: 1 digital cartoon(s).

Images, Alexander Turnbull Library

A man representing the South Island stands under an umbrella representing 'hope' to shelter from a bucketload of water representing 'misfortune'. Context - in the last year apart from the usual droughts and floods the South Island has suffered the Pike River Mine disaster on 19 November 2010 in which 29 coal miners were killed, the 7.1 earthquake on 4 September 2010 in which there was a lot of damage but no deaths and now on 22 February 2011 a 6.3 magnitude earthquake which has probably killed more than 200 people (at this point the number is still not known) and caused more severe damage. The reason the apparently lesser magnitude quake caused more destruction is because it was very shallow, was in the middle of the day and struck very close to the centre of the city. Quantity: 1 digital cartoon(s).

Research papers, University of Canterbury Library

This manuscript provides a critical examination of the ground motions recorded in the near-source region resulting from the 22 February 2011 Christchurch earthquake. Particular attention is given to reconciling the observed spatial distribution of ground motions in terms of physical phenomena related to source, path and site effects. The large number of near-source observed strong ground motions show clear evidence of: forward-directivity, basin generated surface waves, liquefaction and other significant nonlinear site response. The pseudo-acceleration response spectra (SA) amplitudes and significant duration of strong motions agree well with empirical prediction models, except at long vibration periods where the influence of basin-generated surface waves and nonlinear site response are significant and not adequately accounted for in empirical SA models. Pseudo-acceleration response spectra are also compared with those observed in the 4 September 2010 Darfield earthquake and routine design response spectra used in order to emphasise the amplitude of ground shaking and elucidate the importance of local geotechnical characteristics on surface ground motions. The characteristics of the observed vertical component accelerations are shown to be strongly dependent on source-to-site distance and are comparable with those from the 4 September 2010 Darfield earthquake, implying the large amplitudes observed are simply a result of many observations at close distances rather than a peculiar source effect.

Research papers, University of Canterbury Library

The 22 February 2011, Mw6.2-6.3 Christchurch earthquake is the most costly earthquake to affect New Zealand, causing 181 fatalities and severely damaging thousands of residential and commercial buildings, and most of the city lifelines and infrastructure. This manuscript presents an overview of observed geotechnical aspects of this earthquake as well as some of the completed and on-going research investigations. A unique aspect, which is particularly emphasized, is the severity and spatial extent of liquefaction occurring in native soils. Overall, both the spatial extent and severity of liquefaction in the city was greater than in the preceding 4th September 2010 Darfield earthquake, including numerous areas that liquefied in both events. Liquefaction and lateral spreading, variable over both large and short spatial scales, affected commercial structures in the Central Business District (CBD) in a variety of ways including: total and differential settlements and tilting; punching settlements of structures with shallow foundations; differential movements of components of complex structures; and interaction of adjacent structures via common foundation soils. Liquefaction was most severe in residential areas located to the east of the CBD as a result of stronger ground shaking due to the proximity to the causative fault, a high water table approximately 1m from the surface, and soils with composition and states of high susceptibility and potential for liquefaction. Total and differential settlements, and lateral movements, due to liquefaction and lateral spreading is estimated to have severely compromised 15,000 residential structures, the majority of which otherwise sustained only minor to moderate damage directly due to inertial loading from ground shaking. Liquefaction also had a profound effect on lifelines and other infrastructure, particularly bridge structures, and underground services. Minor damage was also observed at flood stop banks to the north of the city, which were more severely impacted in the 4th September 2010 Darfield earthquake. Due to the large high-frequency ground motion in the Port hills numerous rock falls and landslides also occurred, resulting in several fatalities and rendering some residential areas uninhabitable.

Research papers, University of Canterbury Library

The Canterbury Earthquakes of 2010-2011, in particular the 4th September 2010 Darfield earthquake and the 22nd February 2011 Christchurch earthquake, produced severe and widespread liquefaction in Christchurch and surrounding areas. The scale of the liquefaction was unprecedented, and caused extensive damage to a variety of man-made structures, including residential houses. Around 20,000 residential houses suffered serious damage as a direct result of the effects of liquefaction, and this resulted in approximately 7000 houses in the worst-hit areas being abandoned. Despite the good performance of light timber-framed houses under the inertial loads of the earthquake, these structures could not withstand the large loads and deformations associated with liquefaction, resulting in significant damage. The key structural component of houses subjected to liquefaction effects was found to be their foundations, as these are in direct contact with the ground. The performance of house foundations directly influenced the performance of the structure as a whole. Because of this, and due to the lack of research in this area, it was decided to investigate the performance of houses and in particular their foundations when subjected to the effects of liquefaction. The data from the inspections of approximately 500 houses conducted by a University of Canterbury summer research team following the 4th September 2010 earthquake in the worst-hit areas of Christchurch were analysed to determine the general performance of residential houses when subjected to high liquefaction loads. This was followed by the detailed inspection of around 170 houses with four different foundation types common to Christchurch and New Zealand: Concrete perimeter with short piers constructed to NZS3604, concrete slab-on-grade also to NZS3604, RibRaft slabs designed by Firth Industries and driven pile foundations. With a focus on foundations, floor levels and slopes were measured, and the damage to all areas of the house and property were recorded. Seven invasive inspections were also conducted on houses being demolished, to examine in more detail the deformation modes and the causes of damage in severely affected houses. The simplified modelling of concrete perimeter sections subjected to a variety of liquefaction-related scenarios was also performed, to examine the comparative performance of foundations built in different periods, and the loads generated under various bearing loss and lateral spreading cases. It was found that the level of foundation damage is directly related to the level of liquefaction experienced, and that foundation damage and liquefaction severity in turn influence the performance of the superstructure. Concrete perimeter foundations were found to have performed most poorly, suffering high local floor slopes and being likely to require foundation repairs even when liquefaction was low enough that no surface ejecta was seen. This was due to their weak, flexible foundation structure, which cannot withstand liquefaction loads without deforming. The vulnerability of concrete perimeter foundations was confirmed through modelling. Slab-on-grade foundations performed better, and were unlikely to require repairs at low levels of liquefaction. Ribraft and piled foundations performed the best, with repairs unlikely up to moderate levels of liquefaction. However, all foundation types were susceptible to significant damage at higher levels of liquefaction, with maximum differential settlements of 474mm, 202mm, 182mm and 250mm found for concrete perimeter, slab-on-grade, ribraft and piled foundations respectively when subjected to significant lateral spreading, the most severe loading scenario caused by liquefaction. It was found through the analysis of the data that the type of exterior wall cladding, either heavy or light, and the number of storeys, did not affect the performance of foundations. This was also shown through modelling for concrete perimeter foundations, and is due to the increased foundation strengths provided for heavily cladded and two-storey houses. Heavy roof claddings were found to increase the demands on foundations, worsening their performance. Pre-1930 concrete perimeter foundations were also found to be very vulnerable to damage under liquefaction loads, due to their weak and brittle construction.

Research papers, University of Canterbury Library

The Canterbury Earthquake Sequence (CES), induced extensive damage in residential buildings and led to over NZ$40 billion in total economic losses. Due to the unique insurance setting in New Zealand, up to 80% of the financial losses were insured. Over the CES, the Earthquake Commission (EQC) received more than 412,000 insurance claims for residential buildings. The 4 September 2010 earthquake is the event for which most of the claims have been lodged with more than 138,000 residential claims for this event only. This research project uses EQC claim database to develop a seismic loss prediction model for residential buildings in Christchurch. It uses machine learning to create a procedure capable of highlighting critical features that affected the most buildings loss. A future study of those features enables the generation of insights that can be used by various stakeholders, for example, to better understand the influence of a structural system on the building loss or to select appropriate risk mitigation measures. Previous to the training of the machine learning model, the claim dataset was supplemented with additional data sourced from private and open access databases giving complementary information related to the building characteristics, seismic demand, liquefaction occurrence and soil conditions. This poster presents results of a machine learning model trained on a merged dataset using residential claims from the 4 September 2010.

Research papers, University of Canterbury Library

The objective of this study is to examine the influence of near-fault motions on liquefaction triggering in Christchurch and neighboring towns during the 2010-2011 Canterbury earthquake sequence (CES). The CES began with the 4 September 2010, Mw7.1 Darfield earthquake and included up to ten events that triggered liquefaction. However, most notably, widespread liquefaction was induced by the Darfield earthquake and the Mw6.2, 22 February 2011 Christchurch earthquake. Of particular relevance to this study is the forward directivity effects that were prevalent in the motions recorded during the Darfield earthquake, and to a much lesser extent, during the Christchurch earthquake. A 2D variant of the Richart-Newmark fatigue theory was used to compute the equivalent number of cycles (neq) for the ground motions, where volumetric strain was used as the damage metric. This study is unique because it considers the contribution and phasing of both the fault-normal and fault-parallel components of motion on neq and the magnitude scaling factor (MSF). It was found that when the fault-normal and fault-parallel motions were treated individually, the former yielded a lower neq than the latter. Additionally, when the combined effects of fault-normal and fault-parallel components were considered, it was found that the MSF were higher than those commonly used. This implies that motions containing near-fault effects are less demanding on the soil than motions that do not. This may be one of several factors that resulted in less severe liquefaction occurring during the Darfield earthquake than the Christchurch earthquake.