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Research papers, University of Canterbury Library

Results from a series of 1D seismic effective stress analyses of natural soil deposits from Christchurch are summarized. The analysed soil columns include sites whose performance during the 2010-2011 Canterbury earthquakes varied significantly, from no liquefaction manifestation at the ground surface to very severe liquefaction, in which case a large area of the site was covered by thick soil ejecta. Key soil profile characteristics and response mechanisms affecting the severity of surface liquefaction manifestation and subsequent damage are explored. The influence of shaking intensity on the triggering and contribution of these mechanisms is also discussed. Careful examination of the results highlights the importance of considering the deposit as a whole, i.e. a system of layers, including interactions between layers in the dynamic response and through pore water pressure redistribution and water flow.

Research papers, University of Canterbury Library

In 2010 and 2011 a series of earthquakes hit the central region of Canterbury, New Zealand, triggering widespread and damaging liquefaction in the area of Christchurch. Liquefaction occurred in natural clean sand deposits, but also in silty (fines-containing) sand deposits of fluvial origin. Comprehensive research efforts have been subsequently undertaken to identify key factors that influenced liquefaction triggering and severity of its manifestation. This research aims at evaluating the effects of fines content, fabric and layered structure on the cyclic undrained response of silty soils from Christchurch using Direct Simple Shear (DSS) tests. This poster outlines preliminary calibration and verification DSS tests performed on a clean sand to ensure reliability of testing procedures before these are applied to Christchurch soils.

Images, UC QuakeStudies

Wheelbarrows belonging to the Student Volunteer Army stacked up outside the UCSA's "Big Top". The tent was erected to provide support for students at the University of Canterbury in the aftermath of the 22 February 2011 earthquake.

Images, UC QuakeStudies

University of Canterbury Vice-Chancellor Rod Carr speaking with UCSA President Kohan McNab and former Chancellor Rex Williams, inside the UCSA's "Big Top" tent. The tent was erected in the UCSA car park to provide support for students in the aftermath of the 22 February 2011 earthquake. Around them students have gathered to watch a local musician play. The student have spent the day clearing liquefaction from Christchurch properties as part of the Student Volunteer Army.

Images, UC QuakeStudies

University of Canterbury Vice-Chancellor Rod Carr speaking with UCSA President Kohan McNab and former Chancellor Rex Williams, inside the UCSA's "Big Top" tent. The tent was erected in the UCSA car park to provide support for students in the aftermath of the 22 February 2011 earthquake. Around them students have gathered to watch a local musician play. The student have spent the day clearing liquefaction from Christchurch properties as part of the Student Volunteer Army.

Images, UC QuakeStudies

UCSA President Kohan McNab addressing students at the University of Canterbury inside the UCSA's "Big Top" tent. The tent was erected in the UCSA car park to provide support for students in the aftermath of the 22 February 2011 earthquake. The students have spent the day clearing liquefaction from Christchurch properties as part of the Student Volunteer Army. To the right of McNab, a local musician who has been entertaining the students can be seen.

Images, eqnz.chch.2010

Yes, it was a joke. The tours, that is, not the yard filled with earthquake-caused sand volcanos. They were very real. You can see one covering the driveway in this photo. The signs read as follows. "Tours run 1/2 hourly. $5.25 admission. Eftpos unavailable." "If you think this is bad... you should see the back!"

Images, UC QuakeStudies

Student leaders, including UCSA President Kohan McNab and Sam Johnston, head of the Student Volunteer Army, leading students from the University of Canterbury in a two minute silence to remember those who died in the 22 February 2011 earthquake. They have stood on top of the ENSOC fire engine to address the crowd, and the event has been filmed from that vantage point. The students have been enjoying a barbeque lunch break in Burwood Park after volunteering to dig up liquefaction as part of the Student Volunteer Army.

Images, UC QuakeStudies

A house on Avonside Drive showing damage from the 4 September 2010 earthquake. Numerous cracks in the masonry can be seen, and several sections of brick have fallen off the walls. The building's porch has also collapsed. A pile of dried liquefaction is visible in the driveway.

Images, UC QuakeStudies

Labour Party leader Phil Goff speaking to members of the Student Volunteer Army in the UCSA car park outside the UCSA's "Big Top" tent. The tent was erected to provide support for students at the University of Canterbury in the aftermath of the 22 February 2011 earthquake.

Images, UC QuakeStudies

A house on Avonside Drive showing damage from the 4 September 2010 earthquake. Numerous cracks in the masonry can be seen, and several sections of brick have fallen off the walls. The building's porch has also collapsed. A pile of dried liquefaction is visible in the driveway.

Images, UC QuakeStudies

A photograph of the earthquake damage to the entrance of a driveway on Glenarm Terrace. A large hole in the foreground has had a road cone placed inside it. Other large cracks and liquefaction can bee seen. A man in overalls has parked his van next to the damage.

Research papers, University of Canterbury Library

Liquefaction-induced lateral spreading during earthquakes poses a significant hazard to the built environment, as observed in Christchurch during the 2010 to 2011 Canterbury Earthquake Sequence (CES). It is critical that geotechnical earthquake engineers are able to adequately predict both the spatial extent of lateral spreads and magnitudes of associated ground movements for design purposes. Published empirical and semi-empirical models for predicting lateral spread displacements have been shown to vary by a factor of <0.5 to >2 from those measured in parts of Christchurch during CES. Comprehensive post- CES lateral spreading studies have clearly indicated that the spatial distribution of the horizontal displacements and extent of lateral spreading along the Avon River in eastern Christchurch were strongly influenced by geologic, stratigraphic and topographic features.

Images, UC QuakeStudies

A collection of shovels from the Student Volunteer Army in the car park of the USCA. The shovels have been returned by students after a day of clearing liquefaction from Christchurch properties. Behind them the UCSA's "Big Top" tent can be seen, which was erected to provide support for students at the University of Canterbury in the aftermath of the 22 February 2011 earthquake.

Images, UC QuakeStudies

A collection of wheelbarrows from the Student Volunteer Army in the car park of the USCA. The wheelbarrows have been returned by students after a day of clearing liquefaction from Christchurch properties. Behind them the UCSA's "Big Top" tent can be seen, which was erected to provide support for students at the University of Canterbury in the aftermath of the 22 February 2011 earthquake.

Research papers, The University of Auckland Library

This thesis presents the application of data science techniques, especially machine learning, for the development of seismic damage and loss prediction models for residential buildings. Current post-earthquake building damage evaluation forms are developed for a particular country in mind. The lack of consistency hinders the comparison of building damage between different regions. A new paper form has been developed to address the need for a global universal methodology for post-earthquake building damage assessment. The form was successfully trialled in the street ‘La Morena’ in Mexico City following the 2017 Puebla earthquake. Aside from developing a framework for better input data for performance based earthquake engineering, this project also extended current techniques to derive insights from post-earthquake observations. Machine learning (ML) was applied to seismic damage data of residential buildings in Mexico City following the 2017 Puebla earthquake and in Christchurch following the 2010-2011 Canterbury earthquake sequence (CES). The experience showcased that it is readily possible to develop empirical data only driven models that can successfully identify key damage drivers and hidden underlying correlations without prior engineering knowledge. With adequate maintenance, such models have the potential to be rapidly and easily updated to allow improved damage and loss prediction accuracy and greater ability for models to be generalised. For ML models developed for the key events of the CES, the model trained using data from the 22 February 2011 event generalised the best for loss prediction. This is thought to be because of the large number of instances available for this event and the relatively limited class imbalance between the categories of the target attribute. For the CES, ML highlighted the importance of peak ground acceleration (PGA), building age, building size, liquefaction occurrence, and soil conditions as main factors which affected the losses in residential buildings in Christchurch. ML also highlighted the influence of liquefaction on the buildings losses related to the 22 February 2011 event. Further to the ML model development, the application of post-hoc methodologies was shown to be an effective way to derive insights for ML algorithms that are not intrinsically interpretable. Overall, these provide a basis for the development of ‘greybox’ ML models.

Research Papers, Lincoln University

The September and February earthquakes were terrifying and devastating. In February, 185 people were killed (this number excludes post earthquake related deaths) and several thousand injured. Damage to infrastructure above and below ground in and around Christchurch was widespread and it will take many years and billions of dollars to rebuild. The ongoing effects of the big quakes and aftershocks are numerous, with the deepest impact being on those who lost family and friends, their livelihoods and homes. What did Cantabrians do during the days, weeks and months of uncertainty and how have we responded? Many grieved, some left, some stayed, some arrived, many shovelled (liquefaction left thousands of tons of silt to be removed from homes and streets), and some used their expertise or knowledge to help in the recovery. This book highlights just some of the projects staff and students from The Faculty of Environment, Society and Design have been involved in from September 2010 to October 2012. The work is ongoing and the plan is to publish another book to document progress and new projects.

Research papers, The University of Auckland Library

This thesis presents an assessment of historic seismic performance of the New Zealand stopbank network from the 1968 Inangahua earthquake through to the 2016 Kaikōura earthquake. An overview of the types of stopbanks and the main aspects of the design and construction of earthen stopbanks was presented. Stopbanks are structures that are widely used on the banks of rivers and other water bodies to protect against the impact of flood events. Earthen stopbanks are found to be the most used for such protection measures. Different stopbank damage or failure modes that may occur due to flooding or earthquake excitation were assessed with a focus on past earthquakes internationally, and examples of these damage and failure modes were presented. Stopbank damage and assessment reports were collated from available reconnaissance literature to develop the first geospatial database of stopbank damage observed in past earthquakes in New Zealand. Damage was observed in four earthquakes over the past 50 years, with a number of earthquakes resulting in no stopbank damage. The damage database therefore focussed on the Edgecumbe, Darfield, Christchurch and Kaikōura earthquakes. Cracking of the crest and liquefaction-induced settlement were the most common forms of damage observed. To understand the seismic demand on the stopbank network in past earthquakes, geospatial analyses were undertaken to approximate the peak ground acceleration (PGA) across the stopbank network for ten large earthquakes that have occurred in New Zealand over the past 50 years. The relationship between the demand, represented by the peak ground acceleration (PGA) and damage is discussed and key trends identified. Comparison of the seismic demand and the distribution of damage suggested that the seismic performance of the New Zealand stopbank network has been generally good across all events considered. Although a significant length of the stopbank networks were exposed to high levels of shaking in past events, the overall damage length was a small percentage of this. The key aspect controlling performance was the performance of the underlying foundation soils and the effect of this on the stopbank structure and stability.

Research papers, Victoria University of Wellington

©2019. American Geophysical Union. All Rights Reserved. Earthquakes have been inferred to induce hydrological changes in aquifers on the basis of either changes to well water-levels or tidal behavior, but the relationship between these changes remains unclear. Here, changes in tidal behavior and water-levels are quantified using a hydrological network monitoring gravel aquifers in Canterbury, New Zealand, in response to nine earthquakes (of magnitudes M w 5.4 to 7.8) that occurred between 2008 and 2015. Of the 161 wells analyzed, only 35 contain water-level fluctuations associated with “Earth + Ocean” (7) or “Ocean” (28) tides. Permeability reduction manifest as changes in tidal behavior and increased water-levels in the near field of the Canterbury earthquake sequence of 2010–2011 support the hypothesis of shear-induced consolidation. However, tidal behavior and water-level changes rarely occurred simultaneously (~2%). Water-level changes that occurred with no change in tidal behavior reequilibrated at a new postseismic level more quickly (on timescales of ~50 min) than when a change in tidal behavior occurred (~240 min to 10 days). Water-level changes were more than likely to occur above a peak dynamic stress of ~50 kPa and were more than likely to not occur below ~10 kPa. The minimum peak dynamic stress required for a tidal behavior change to occur was ~0.2 to 100 kPa.

Research papers, University of Canterbury Library

1. INTRODUCTION. Earthquakes and geohazards, such as liquefaction, landslides and rock falls, constitute a major risk for New Zealand communities and can have devastating impacts as the Canterbury 2010/2011 experience shows. Development patterns expose communities to an array of natural hazards, including tsunamis, floods, droughts, and sea level rise amongst others. Fostering community resilience is therefore vitally important. As the rhetoric of resilience is mainstreamed into the statutory framework, a major challenge emerges: how can New Zealand operationalize this complex and sometimes contested concept and build ‘community capitals’? This research seeks to provide insights to this question by critically evaluating how community capitals are conceptualized and how they can contribute to community resilience in the context of the Waimakariri District earthquake recovery and regeneration process.

Images, UC QuakeStudies

A car on Rowses Road has its entire front half embedded in liquefaction after falling into a sink hole. The photographer comments, "Perhaps the most impressively stuck car was this small silver hatchback that went head first into a large hole in a street just off Shortland Street (between Shortland and Breezes Road) in Aranui. The rear hatch was open when we came across it. Apparently there had been one person and a dog inside but they managed to escape. The silt has now settled around and inside the car, making the vehicle an intimidating monument to the earthquake".

Images, UC QuakeStudies

A car on Rowses Road has its entire front half embedded in liquefaction after falling into a sink hole. The photographer comments, "Perhaps the most impressively stuck car was this small silver hatchback that went head first into a large hole in a street just off Shortland Street (between Shortland and Breezes Road) in Aranui. The rear hatch was open when we came across it. Apparently there had been one person and a dog inside but they managed to escape. The silt has now settled around and inside the car, making the vehicle an intimidating monument to the earthquake".

Images, UC QuakeStudies

A car on Rowses Road has its entire front half embedded in liquefaction after falling into a sink hole. The photographer comments, "Perhaps the most impressively stuck car was this small silver hatchback that went head first into a large hole in a street just off Shortland Street (between Shortland and Breezes Road) in Aranui. The rear hatch was open when we came across it. Apparently there had been one person and a dog inside but they managed to escape. The silt has now settled around and inside the car, making the vehicle an intimidating monument to the earthquake".

Images, UC QuakeStudies

A car on Rowses Road has its entire front half embedded in liquefaction after falling into a sink hole. Two other cars have their wheels stuck in the silt. The photographer comments, "Perhaps the most impressively stuck car was this small silver hatchback that went head first into a large hole in a street just off Shortland Street (between Shortland and Breezes Road) in Aranui. The rear hatch was open when we came across it. Apparently there had been one person and a dog inside but they managed to escape. The silt has now settled around and inside the car, making the vehicle an intimidating monument to the earthquake".

Images, UC QuakeStudies

A car on Rowses Road has its entire front half embedded in liquefaction after falling into a sink hole. Behind it, another car has its wheels stuck in the silt. The photographer comments, "Perhaps the most impressively stuck car was this small silver hatchback that went head first into a large hole in a street just off Shortland Street (between Shortland and Breezes Road) in Aranui. The rear hatch was open when we came across it. Apparently there had been one person and a dog inside but they managed to escape. The silt has now settled around and inside the car, making the vehicle an intimidating monument to the earthquake".

Images, UC QuakeStudies

A car on Rowses Road has its entire front half embedded in liquefaction after falling into a sink hole. Two other cars have their wheels stuck in the silt. The photographer comments, "Perhaps the most impressively stuck car was this small silver hatchback that went head first into a large hole in a street just off Shortland Street (between Shortland and Breezes Road) in Aranui. The rear hatch was open when we came across it. Apparently there had been one person and a dog inside but they managed to escape. The silt has now settled around and inside the car, making the vehicle an intimidating monument to the earthquake".

Images, UC QuakeStudies

A car on Rowses Road has its entire front half embedded in liquefaction after falling into a sink hole. Behind it, another car has its wheels stuck in the silt. The photographer comments, "Perhaps the most impressively stuck car was this small silver hatchback that went head first into a large hole in a street just off Shortland Street (between Shortland and Breezes Road) in Aranui. The rear hatch was open when we came across it. Apparently there had been one person and a dog inside but they managed to escape. The silt has now settled around and inside the car, making the vehicle an intimidating monument to the earthquake".