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Images, UC QuakeStudies

An image from the All Right? 'Compliments' campaign, for the CDHB website. The image reads, "Your aroha really helps. Let's remember it's often the simple things that bring the most joy." The image also includes the web address of the All Right? Facebook page.

Images, UC QuakeStudies

An image from the All Right? 'Compliments' campaign, for the CDHB website. The image reads, "Thanks for never giving up. Let's remember it's often the simple things that bring the most joy." The image also includes the web address of the All Right? Facebook page.

Images, UC QuakeStudies

An image from the All Right? 'Compliments' campaign, for the CDHB website. The image reads, "Your smile is life changing. Let's remember it's often the simple things that bring the most joy." The image also includes the web address of the All Right? Facebook page.

Images, UC QuakeStudies

A photograph of the Carlton Hotel on the corner of Papanui Road and Bealey Avenue. The top storey of the building's walls have crumbled, the bricks spilling onto the street below. Steel bracing has been placed against the building to the left.

Articles, UC QuakeStudies

A PDF copy of a billboard design from the All Right? 'Compliments' campaign. The billboard reads, "You make the tough times better. Let's remember it's often the simple things that bring the most joy." The design also includes the web address of the All Right? Facebook page.

Images, UC QuakeStudies

Members of the public view the damaged tower of Christ Church Cathedral. Bracing has been placed on the front wall to the right to limit further damage. In the centre of the crowd stands a wire cage filled with stones. After the earthquake, love notes to Christchurch were written on the stones.

Images, UC QuakeStudies

A photograph of a room in the Diabetes Centre. The furniture in the centre of the room has been covered with a tarpaulin. In the background, the panelling has been removed from one of the walls, exposing the wooden frame, wires, and pipes underneath.

Images, UC QuakeStudies

A dairy on the corner of Gloucester and Woodham Streets. The top wall of the building has crumbled onto the street. A tarpaulin has been placed over the hole to prevent weather damage inside the building. Fencing and road cones cordon off the building along the street.

Articles, UC QuakeStudies

A PDF copy of a billboard design from the All Right? 'Compliments' campaign. The billboard reads, "People love the little things you do. Let's remember it's often the simple things that bring the most joy." The design also includes the web address of the All Right? Facebook page.

Images, UC QuakeStudies

A view down Victoria Street from the corner of Victoria Street and Bealey Avenue. On the left is the damaged Knox Church, where the brick has crumbled but the wooden roof frame is still intact. Behind is the the BDO building and on the left is an empty demolition site.

Research papers, University of Canterbury Library

The previously unknown Greendale Fault was buried beneath the Canterbury Plains and ruptured in the September 4th 2010 moment magnitude (Mw) 7.1 Darfield Earthquake. The Darfield Earthquake and subsequent Mw 6 or greater events that caused damage to Christchurch highlight the importance of unmapped faults near urban areas. This thesis examines the morphology, age and origin of the Canterbury Plains together with the paleoseismology and surface-rupture displacement distributions of the Greendale Fault. It offers new insights into the surface-rupture characteristics, paleoseismology and recurrence interval of the Greendale Fault and related structures involved in the 2010 Darfield Earthquake. To help constrain the timing of the penultimate event on the Greendale Fault the origin and age of the faulted glacial outwash deposits have been examined using sedimentological analysis of gravels and optically stimulated luminescence (OSL) dating combined with analysis of GPS and LiDAR survey data. OSL ages from this and other studies, and the analysis of surface paleochannel morphology and subsurface gravel deposits indicate distinct episodes of glacial outwash activity across the Canterbury Plains, at ~20 to 24 and ~28 to 33 kyr separated by a hiatus in sedimentation possibly indicating an interstadial period. These data suggest multiple glacial periods between ~18 and 35 kyr which may have occurred throughout the Canterbury region and wider New Zealand. A new model for the Waimakariri Fan is proposed where aggradation is mainly achieved during episodic sheet flooding with the primary river channel location remaining approximately fixed. The timing, recurrence interval and displacements of the penultimate surface-rupturing earthquake on the Greendale Fault have been constrained by trenching the scarp produced in 2010 at two locations. These excavations reveal a doubling of the magnitude of surface displacement at depths of 2-4 m. Aided by OSL ages of sand lenses in the gravel deposits, this factor-of-two increase is interpreted to indicate that in the central section of the Greendale Fault the penultimate surface-rupturing event occurred between ca. 20 and 30 kyr ago. The Greendale Fault remained undetected prior to the Darfield earthquake because the penultimate fault scarp was eroded and buried during Late Pleistocene alluvial activity. The Darfield earthquake rupture terminated against the Hororata Anticline Fault (HAF) in the west and resulted in up to 400 mm of uplift on the Hororata Anticline immediately above the HAF. Folding in 2010 is compared to Quaternary and younger deformation across the anticline recorded by a seismic reflection line, GPS-measured topographic profiles along fluvial surfaces, and river channel sinuosity and morphology. It is concluded that the HAF can rupture during earthquakes dissimilar to the 2010 event that may not be triggered by slip on the Greendale Fault. Like the Greendale Fault geomorphic analyses provide no evidence for rupture of the HAF in the last 18 kyr, with the average recurrence interval for the late Quaternary inferred to be at least ~10 kyr. Surface rupture of the Greendale Fault during the Darfield Earthquake produced one of the most accessible and best documented active fault displacement and geometry datasets in the world. Surface rupture fracture patterns and displacements along the fault were measured with high precision using real time kinematic (RTK) GPS, tape and compass, airborne light detection and ranging (LiDAR), and aerial photos. This allowed for detailed analysis of the cumulative strike-slip displacement across the fault zone, displacement gradient (ground shear strain) and the type of displacement (i.e. faulting or folding). These strain profiles confirm that the rupture zone is generally wide (~30 to ~300 metres) with >50% of displacement (often 70-80%) accommodated by ground flexure rather than discrete fault slip and ground cracking. The greatest fault-zone widths and highest proportions of folding are observed at fault stepovers.

Images, UC QuakeStudies

The damaged Knox Church on Bealey Avenue. The brick walls have collapsed, exposing the wooden structure beneath. The photographer comments, "Bealey Avenue is open to traffic, as are many of the side streets, and the damage to buildings along this street is quite impressive and perhaps just a small taste of the damage that lies beyond the cordon ... At the Hagley Park end of Bealey Avenue lies the Knox Church. This church suffered in the first earthquake and featured in the news a fair bit at the time. It's crazy to think that all that appeared to be damaged then were some bricks that had fallen from near the roof. Now, Knox Church is all but a wooden frame holding up a roof. It's eerie to drive past this large church and be able to look straight through it to trees on the other side".

Research papers, University of Canterbury Library

Geosynthetic reinforced soil (GRS) walls involve the use of geosynthetic reinforcement (polymer material) within the retained backfill, forming a reinforced soil block where transmission of overturning and sliding forces on the wall to the backfill occurs. Key advantages of GRS systems include the reduced need for large foundations, cost reduction (up to 50%), lower environmental costs, faster construction and significantly improved seismic performance as observed in previous earthquakes. Design methods in New Zealand have not been well established and as a result, GRS structures do not have a uniform level of seismic and static resistance; hence involve different risks of failure. Further research is required to better understand the seismic behaviour of GRS structures to advance design practices. The experimental study of this research involved a series of twelve 1-g shake table tests on reduced-scale (1:5) GRS wall models using the University of Canterbury shake-table. The seismic excitation of the models was unidirectional sinusoidal input motion with a predominant frequency of 5Hz and 10s duration. Seismic excitation of the model commenced at an acceleration amplitude level of 0.1g and was incrementally increased by 0.1g in subsequent excitation levels up to failure (excessive displacement of the wall panel). The wall models were 900mm high with a full-height rigid facing panel and five layers of Microgird reinforcement (reinforcement spacing of 150mm). The wall panel toe was founded on a rigid foundation and was free to slide. The backfill deposit was constructed from dry Albany sand to a backfill relative density, Dr = 85% or 50% through model vibration. The influence of GRS wall parameters such as reinforcement length and layout, backfill density and application of a 3kPa surcharge on the backfill surface was investigated in the testing sequence. Through extensive instrumentation of the wall models, the wall facing displacements, backfill accelerations, earth pressures and reinforcement loads were recorded at the varying levels of model excitation. Additionally, backfill deformation was also measured through high-speed imaging and Geotechnical Particle Image Velocimetry (GeoPIV) analysis. The GeoPIV analysis enabled the identification of the evolution of shear strains and volumetric strains within the backfill at low strain levels before failure of the wall thus allowing interpretations to be made regarding the strain development and shear band progression within the retained backfill. Rotation about the wall toe was the predominant failure mechanism in all excitation level with sliding only significant in the last two excitation levels, resulting in a bi-linear displacement acceleration curve. An increase in acceleration amplification with increasing excitation was observed with amplification factors of up to 1.5 recorded. Maximum seismic and static horizontal earth pressures were recorded at failure and were recorded at the wall toe. The highest reinforcement load was recorded at the lowest (deepest in the backfill) reinforcement layer with a decrease in peak load observed at failure, possibly due to pullout failure of the reinforcement layer. Conversely, peak reinforcement load was recorded at failure for the top reinforcement layer. The staggered reinforcement models exhibited greater wall stability than the uniform reinforcement models of L/H=0.75. However, similar critical accelerations were determined for the two wall models due to the coarseness of excitation level increments of 0.1g. The extended top reinforcements were found to restrict the rotational component of displacement and prevented the development of a preliminary shear band at the middle reinforcement layer, contributing positively to wall stability. Lower acceleration amplification factors were determined for the longer uniform reinforcement length models due to reduced model deformation. A greater distribution of reinforcement load towards the top two extended reinforcement layers was also observed in the staggered wall models. An increase in model backfill density was observed to result in greater wall stability than an increase in uniform reinforcement length. Greater acceleration amplification was observed in looser backfill models due to their lower model stiffness. Due to greater confinement of the reinforcement layers, greater reinforcement loads were developed in higher density wall models with less wall movement required to engage the reinforcement layers and mobilise their resistance. The application of surcharge on the backfill was observed to initially increase the wall stability due to greater normal stresses within the backfill but at greater excitation levels, the surcharge contribution to wall destabilising inertial forces outweighs its contribution to wall stability. As a result, no clear influence of surcharge on the critical acceleration of the wall models was observed. Lower acceleration amplification factors were observed for the surcharged models as the surcharge acts as a damper during excitation. The application of the surcharge also increases the magnitude of reinforcement load developed due to greater confinement and increased wall destabilising forces. The rotation of the wall panel resulted in the progressive development of shears surface with depth that extended from the backfill surface to the ends of the reinforcement (edge of the reinforced soil block). The resultant failure plane would have extended from the backfill surface to the lowest reinforcement layer before developing at the toe of the wall, forming a two-wedge failure mechanism. This is confirmed by development of failure planes at the lowest reinforcement layer (deepest with the backfill) and at the wall toe observed at the critical acceleration level. Key observations of the effect of different wall parameters from the GeoPIV results are found to be in good agreement with conclusions developed from the other forms of instrumentation. Further research is required to achieve the goal of developing seismic guidelines for GRS walls in geotechnical structures in New Zealand. This includes developing and testing wall models with a different facing type (segmental or wrap-around facing), load cell instrumentation of all reinforcement layers, dynamic loading on the wall panel and the use of local soils as the backfill material. Lastly, the limitations of the experimental procedure and wall models should be understood.

Research papers, University of Canterbury Library

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.

Research papers, University of Canterbury Library

This article presents a quantitative case study on the site amplification effect observed at Heathcote Valley, New Zealand, during the 2010-2011 Canterbury earthquake sequence for 10 events that produced notable ground acceleration amplitudes up to 1.4g and 2.2g in the horizontal and vertical directions, respectively. We performed finite element analyses of the dynamic response of the valley, accounting for the realistic basin geometry and the soil non-linear response. The site-specific simulations performed significantly better than both empirical ground motion models and physics based regional-scale ground motion simulations (which empirically accounts for the site effects), reducing the spectral acceleration prediction bias by a factor of two in short vibration periods. However, our validation exercise demonstrated that it was necessary to quantify the level of uncertainty in the estimated bedrock motion using multiple recorded events, to understand how much the simplistic model can over- or under-estimate the ground motion intensities. Inferences from the analyses suggest that the Rayleigh waves generated near the basin edge contributed significantly to the observed high frequency (f>3Hz) amplification, in addition to the amplification caused by the strong soil-rock impedance contrast at the site fundamental frequency. Models with and without considering soil non-linear response illustrate, as expected, that the linear elastic assumption severely overestimates ground motions in high frequencies for strong earthquakes, especially when the contribution of basin edge-generated Rayleigh waves becomes significant. Our analyses also demonstrate that the effect of pressure-dependent soil velocities on the high frequency ground motions is as significant as the amplification caused by the basin edge-generated Rayleigh waves.

Images, UC QuakeStudies

The damaged Cranmer Courts on the corner of Kilmore and Montreal Streets. The corner of the building has crumbled onto the street, which is now littered with broken masonry. Wire fencing placed around the building after the 4 September 2010 earthquake has managed to keep the debris away from the road.

Images, UC QuakeStudies

Damage to the Visitors Centre in Kaiapoi, after the September 4th earthquake. The foundations have lifted at the back of the building, giving it a forward lean. Cables have been attached to the balcony over the walkway and braced to posts cemented into the ground. This is to stop the building from slumping further.

Images, UC QuakeStudies

Damage to the Visitors Centre in Kaiapoi, after the September 4th earthquake. The foundations have lifted at the back of the building, giving it a forward lean. Cables have been attached to the balcony over the walkway and braced to posts cemented into the ground. This is to stop the building from slumping further.

Images, UC QuakeStudies

A damaged building on Cashel Street near Oxford Terrace. The top of the facade has fallen off the building into the street below, taking the awning with it. Bricks from the building still lie on the footpath where they fell. Above, the windows have been braced with plywood. Wire fencing has been placed around the building as a cordon.

Images, UC QuakeStudies

A photograph of the Observatory tower at the Christchurch Arts Centre. There are cracks in the masonry of the tower near where the two storeys join. The cracks formed as a result of the 4 September 2010 earthquake. Wire fencing has been placed at the entrance to the courtyard in front as a cordon.

Images, UC QuakeStudies

A photograph of the earthquake damage to Charlie B's Backpackers on Madras Street. The front of the building has collapsed, the bricks and other rubble spilling onto the road and footpath in front. Many of the walls inside the top storey of the building are now hanging loose from the ceiling.

Images, UC QuakeStudies

Police and army personnel at a cordon checkpoint near the Casino. An armoured vechicle is parked beside the cordon. The photographer comments, "The army are doing a fine job manning the cordon around the city centre. It must be pretty dull work and the weather isn't that flash at the moment. It's still surreal to see armed vehicles guarding entrances to the city though".