Resilience and community spirit have shone through in North Canterbury in the aftermath of the earthquake. With no active civil defence post in operation in Cheviot in the days after the 7.8 quake, a group of locals mobilised a task force to support those in need. Further north at Mendip Hills Station farm manager Simon Lee has been repairing broken water pipes and clearing slips in time for weaning, while on Ben Lissington's dairy farm near Waiau, milk tankers are having to go off the beaten track to get to the rotary shed after a six metre section of the road was destroyed.
A photograph from the All Right? Start With a Smile campaign. Start With A Smile was led by Canterbury Employers' Chamber of Commerce and supported by All Right?. The project encouraged Cantabrians to engage with the thousands of migrants who have moved to Canterbury since the earthquakes.
A photograph from the All Right? Start with A Smile campaign. Start with A Smile was led by Canterbury Employers' Chamber of Commerce and supported by All Right?. The project encouraged Cantabrians to engage with the thousands of migrants who have moved to Canterbury since the earthquakes.
A photograph from the All Right? Start with A Smile campaign. Start with A Smile was led by Canterbury Employers' Chamber of Commerce and supported by All Right?. The project encouraged Cantabrians to engage with the thousands of migrants who have moved to Canterbury since the earthquakes.
A photograph from the All Right? Start with A Smile campaign. Start with A Smile was led by Canterbury Employers' Chamber of Commerce and supported by All Right?. The project encouraged Cantabrians to engage with the thousands of migrants who have moved to Canterbury since the earthquakes.
NUK KORAKO to the Minister of Finance: How does New Zealand’s growing economy and the Government’s commitment to responsible fiscal management mean New Zealand is well-placed to respond to the Kaikōura earthquake? ANDREW LITTLE to the Prime Minister: Has he spoken to relevant Ministers about the lessons learned from the Canterbury earthquakes to ensure people affected by the recent earthquakes have an easier and faster recovery? STUART SMITH to the Minister of Civil Defence: What update can he provide about the Government’s response to the Kaikōura earthquake? RON MARK to the Prime Minister: Can he update the House on the situation in quake-affected areas in the South Island? JAMES SHAW to the Prime Minister: Is he committed to all his Government’s policies? Hon ANNETTE KING to the Minister of Health: Does he stand by his statement that following the Valentine’s Day earthquake this year in Canterbury, “it was timely to review whether any additional mental health and wellbeing support was needed”; if so, will he consider reviewing whether any additional support is needed for Canterbury and Nelson-Marlborough district health boards as a result of the recent earthquakes? JACQUI DEAN to the Minister of Transport: What updates has he received on damage to transport infrastructure following the Kaikōura earthquake? JAN LOGIE to the Minister for Workplace Relations and Safety: What is his response to yesterday’s call from members of the Joint Working Group on Pay Equity Principles for the Government to “immediately right this historic wrong and implement the JWG principles”? JACINDA ARDERN to the Minister for Economic Development: When is he likely to announce a recovery or support package for small businesses in earthquake-affected areas? KANWALJIT SINGH BAKSHI to the Minister of Police: What are New Zealand Police doing to support the Kaikōura community? CHRIS HIPKINS to the Minister of Education: When did she first discuss the potential impact of Monday’s 7.5 earthquake on NCEA and Scholarship exams with the New Zealand Qualifications Authority? IAN McKELVIE to the Minister for Primary Industries: What recent reports has he received on the impact of the recent earthquakes on the primary sector?
Liquefaction features and the geologic environment in which they formed were carefully studied at two sites near Lincoln in southwest Christchurch. We undertook geomorphic mapping, excavated trenches, and obtained hand cores in areas with surficial evidence for liquefaction and areas where no surficial evidence for liquefaction was present at two sites (Hardwick and Marchand). The liquefaction features identified include (1) sand blows (singular and aligned along linear fissures), (2) blisters or injections of subhorizontal dikes into the topsoil, (3) dikes related to the blows and blisters, and (4) a collapse structure. The spatial distribution of these surface liquefaction features correlates strongly with the ridges of scroll bars in meander settings. In addition, we discovered paleoliquefaction features, including several dikes and a sand blow, in excavations at the sites of modern liquefaction. The paleoliquefaction event at the Hardwick site is dated at A.D. 908-1336, and the one at the Marchand site is dated at A.D. 1017-1840 (95% confidence intervals of probability density functions obtained by Bayesian analysis). If both events are the same, given proximity of the sites, the time of the event is A.D. 1019-1337. If they are not, the one at the Marchand site could have been much younger. Taking into account a preliminary liquefaction-triggering threshold of equivalent peak ground acceleration for an Mw 7.5 event (PGA7:5) of 0:07g, existing magnitude-bounded relations for paleoliquefaction, and the timing of the paleoearthquakes and the potential PGA7:5 estimated for regional faults, we propose that the Porters Pass fault, Alpine fault, or the subduction zone faults are the most likely sources that could have triggered liquefaction at the study sites. There are other nearby regional faults that may have been the source, but there is no paleoseismic data with which to make the temporal link.
Shares in the insurance company, Tower, have plunged close to 20 percent today after it said its profits will likely fall more than 16-million dollars because of Canterbury earthquake claims.
A pdf copy of a PowerPoint presentation made for the Water Services Association of Australia conference, about SCIRT's approach to asset investigation after the Canterbury earthquakes of 2010 and 2011.
In this paper Paul Millar outlines the development of the University of Canterbury Quakebox project, a collaborative venture between the UC CEISMIC Canterbury Earthquakes Digital Archive and the New Zealand Institute of Language Brain and Behaviour to preserve people’s earthquake stories for the purposes of research, teaching and commemoration. The project collected over 700 stories on high definition video, and Millar is now looking at using the corpus to underpin a longitudinal study of post-quake experience.
A study of employees affected by the Canterbury earthquakes has found they're more likely to have jobs - and get better pay - than people in similar roles in other parts of the country.
This report provides an initial overview and gap analysis of the multi-hazards interactions that might affect fluvial and pluvial flooding (FPF) hazard in the Ōpāwaho Heathcote catchment. As per the terms of reference, this report focuses on a one-way analysis of the potential effects of multi-hazards on FPF hazard, as opposed to a more complex multi-way analysis of interactions between all hazards. We examined the relationship between FPF hazard and hazards associated with the phenomena of tsunamis; coastal erosion; coastal inundation; groundwater; earthquakes; and mass movements. Tsunamis: Modelling research indicates the worst-case tsunami scenarios potentially affecting the Ōpāwaho Heathcote catchment are far field. Under low probability, high impact tsunami scenarios waves could travel into Pegasus Bay and the Avon-Heathcote Estuary Ihutai, reaching the mouth and lower reaches of the Heathcote catchment and river, potentially inundating and eroding shorelines in sub-catchments 1 to 5, and temporarily blocking fluvial drainage more extensively. Any flooding infrastructure or management actions implemented in the area of tsunami inundation would ideally be resilient to tsunami-induced inundation and erosion. Model results currently available are a first estimate of potential tsunami inundation under contemporary sea and land level conditions. In terms of future large tsunami events, these models likely underestimate effects in riverside sub-catchments, as well as effects under future sea level, shoreline and other conditions. Also of significance when considering different FPF management structures, it is important to be mindful that certain types of flood structures can ‘trap’ inundating water coming from ocean directions, leading to longer flood durations and salinization issues. Coastal erosion: Model predictions indicate that sub-catchments 1 to 3 could potentially be affected by coastal erosion by the timescale of 2065, with sub-catchments 1-6 predicted to be potentially affected by coastal erosion by the time scale of 2115. In addition, the predicted open coast effects of this hazard should not be ignored since any significant changes in the New Brighton Spit open coast would affect erosion rates and exposure of the landward estuary margins, including the shorelines of the Ōpāwaho Heathcote catchment. Any FPF flooding infrastructure or management activities planned for the potentially affected sub-catchments needs to recognise the possibility of coastal erosion, and to have a planned response to the predicted potential shoreline translation. Coastal inundation: Model predictions indicate coastal inundation hazards could potentially affect sub-catchments 1 to 8 by 2065, with a greater area and depth of inundation possible for these same sub-catchments by 2115. Low-lying areas of the Ōpāwaho Heathcote catchment and river channel that discharge into the estuary are highly vulnerable to coastal inundation since elevated ocean and estuary water levels can block the drainage of inland systems, compounding FPF hazards. Coastal inundation can overwhelm stormwater and other drainage network components, and render river dredging options ineffective at best, flood enhancing at worst. A distinction can be made between coastal inundation and coastal erosion in terms of the potential impacts on affected land and assets, including flood infrastructure, and the implications for acceptance, adaptation, mitigation, and/or modification options. That is, responding to inundation could include structural and/or building elevation solutions, since unlike erosion, inundation does not necessarily mean the loss of land. Groundwater: Groundwater levels are of significant but variable concern when examining flooding hazards and management options in the Ōpāwaho Heathcote catchment due to variability in soils, topographies, elevations and proximities to riverine and estuarine surface waterbodies. Much of the Canterbury Plains part of the Ōpāwaho Heathcote catchment has a water table that is at a median depth of <1m from the surface (with actual depth below surface varying seasonally, inter-annually and during extreme meteorological events), though the water table depth rapidly shifts to >6m below the surface in the upper Plains part of the catchment (sub-catchments 13 to 15). Parts of Waltham/Linwood (sub-catchments 5 & 6) and Spreydon (sub-catchment 10) have extensive areas with a particularly high water table, as do sub-catchments 18, 19 and 20 south of the river. In all of the sub-catchments where groundwater depth below surface is shallow, it is necessary to be mindful of cascading effects on liquefaction hazard during earthquake events, including earthquake-induced drainage network and stormwater infrastructure damage. In turn, subsidence induced by liquefaction and other earthquake processes during the CES directly affected groundwater depth below surface across large parts of the central Ōpāwaho Heathcote catchment. The estuary margin of the catchment also faces increasing future challenges with sea level rise, which has the potential to elevate groundwater levels in these areas, compounding existing liquefaction and other earthquake associated multi-hazards. Any increases in subsurface runoff due to drainage system, development or climate changes are also of concern for the loess covered hill slopes due to the potential to enhance mass movement hazards. Earthquakes: Earthquake associated vertical ground displacement and liquefaction have historically affected, or are in future predicted to affect, all Ōpāwaho Heathcote sub-catchments. During the CES, these phenomena induced a significant cascades of changes in the city’s drainage systems, including: extensive vertical displacement and liquefaction induced damage to stormwater ‘greyware’, reducing functionality of the stormwater system; damage to the wastewater system which temporarily lowered groundwater levels and increased stormwater drainage via the wastewater network on the one hand, creating a pollution multi-hazard for FPF on the other hand; liquefaction and vertical displacement induced river channel changes affected drainage capacities; subsidence induced losses in soakage and infiltration capacities; changes occurred in topographic drainage conductivity; estuary subsidence (mainly around the Ōtākaro Avon rivermouth) increased both FPF and coastal inundation hazards; estuary bed uplift (severe around the Ōpāwaho Heathcote margins), reduced tidal prisms and increased bed friction, producing an overall reduction the waterbody’s capacity to efficiently flush catchment floodwaters to sea; and changes in estuarine and riverine ecosystems. All such possible effects need to be considered when evaluating present and future capacities of the Ōpāwaho Heathcote catchment FPF management systems. These phenomena are particularly of concern in the Ōpāwaho Heathcote catchment since stormwater networks must deal with constraints imposed by stream and river channels (past and present), estuarine shorelines and complex hill topography. Mass movements: Mass movements are primarily a risk in the Port Hills areas of the Ōpāwaho Heathcote catchment (sub-catchments 1, 2, 7, 9, 11, 16, 21), though there are one or two small but susceptible areas on the banks of the Ōpāwaho Heathcote River. Mass movements in the form of rockfalls and debris flows occurred on the Port Hills during the CES, resulting in building damage, fatalities and evacuations. Evidence has also been found of earthquake-triggered tunnel gully collapsesin all Port Hill Valleys. Follow-on effects of these mass movements are likely to occur in major future FPF and other hazard events. Of note, elevated groundwater levels, coastal inundation, earthquakes (including liquefaction and other effects), and mass movement exhibit the most extensive levels of multi-hazard interaction with FPF hazard. Further, all of the analysed multi-hazard interactions except earthquakes were found to consistently produce increases in the FPF hazard. The implications of these analyses are that multihazard interactions generally enhance the FPF hazard in the Ōpāwaho Heathcote catchment. Hence, management plans which exclude adjustments for multi-hazard interactions are likely to underestimate the FPF hazard in numerous different ways. In conclusion, although only a one-way analysis of the potential effects of selected multi-hazards on FPF hazard, this review highlights that the Ōpāwaho Heathcote catchment is an inherently multi- hazard prone environment. The implications of the interactions and process linkages revealed in this report are that several significant multi-hazard influences and process interactions must be taken into account in order to design a resilient FPF hazard management strategy.
This report provides an understanding of the nature of Canterbury subcontracting businesses operating in the space of earthquake reconstruction in Christchurch. It offers an in-depth look at the factors that influence the development of their capacity and capability to withstand the impact of volatile economic cycles, including the 2008 global financial crisis and the subsequent 2010/11 Canterbury earthquakes. There have been significant changes to the business models of the 13 subcontracting businesses studied since the earthquakes. These changes can be seen in the ways the case study subcontractors have adapted to cope with the changing demands that the rebuild posed. Apart from the magnitude of reconstruction works and new developments that directly affect the capacity of subcontracting businesses in Canterbury, case studies found that subcontractors’ capacity and capability to meet the demand varies and is influenced by the: subcontractors’ own unique characteristics, which are often shaped by changing circumstances in a dynamic and uncertain recovery process; and internal factors in relation to the company’s goal and employees’ needs
Despite their good performance in terms of their design objectives, many modern code-prescriptive buildings built in Christchurch, New Zealand had to be razed after the 2010-2011 Canterbury earthquakes because repairs were deemed too costly due to widespread sacrificial damage. Clearly a more effective design paradigm is needed to create more resilient structures. Rocking, post-tensioned connections with supplemental energy dissipation can contribute to a damage avoidance designs (DAD). However, few have achieved all three key design objectives of damage-resistant rocking, inherent recentering ability, and repeatable, damage-free energy dissipation for all cycles, which together offer a response which is independent of loading history. Results of experimental tests are presented for a near full-scale rocking beam-column sub-assemblage. A matrix of test results is presented for the system under varying levels of posttensioning, with and without supplemental dampers. Importantly, this parametric study delineates each contribution to response. Practical limitations on posttensioning are identified: a minimum to ensure static structural re-centering, and a maximum to ensure deformability without threadbar yielding. Good agreement between a mechanistic model and experimental results over all parameters and inputs indicates the model is robust and accurate for design. The overall results indicate that it is possible to create a DAD connection where the non-linear force-deformation response is loading history independent and repeatable over numerous loading cycles, without damage, creating the opportunity for the design and implementation of highly resilient structures.
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.
The purpose of this assessment is to compare records of known inanga spawning sites in the waterways of Ōtautahi Christchurch from before and after the Canterbury earthquakes, with particular emphasis on information used in the design of planning methods for spawning site protection.
An UnReinforced clay brick Masonry (URM) chimney is composed of a cantilever URM appendage above a roofline and is considered one of the most earthquake prone non-structural compo¬nents within vintage URM and timber-framed buildings. Observations from past earthquakes including the 1992 Big Bear City earthquake, 1994 Northridge earthquake, 2001 Nisqually earthquake, 2010/2011 Canterbury earthquakes, 2012 Northern Italy earthquakes, and 2014 South Napa earthquake served repeatedly as a reminder of the hazard induced by URM chimneys. The observed failure types included several cases where the adopted retrofit techniques were not adequate to effectively secure chimneys dur¬ing the earthquake. Data collected during the 2010/2011 post-earthquake building assessments in Christchurch and insur¬ance claims are reported herein. Five full-scale solid clay brick URM chimneys which replicated the most encountered geometrical and construction characteristics were subjected to shake table testing. Two chim¬ney samples were representative of the as-built conditions, while three samples were retrofitted using two different configurations of Near-Surface-Mounted (NSM) Carbon-Fibre-Reinforced-Polymer (CFRP) strips and post-tensioning techniques. The adopted securing techniques allowed an increase in seismic acceleration capacity of more than five times for chimneys constructed with ultra-weak mortar and more than twice for chimneys built with weak mortar. http://www.16ibmac.com/
The 2010-2011 Canterbury earthquake sequence, and the resulting extensive data sets on damaged buildings that have been collected, provide a unique opportunity to exercise and evaluate previously published seismic performance assessment procedures. This poster provides an overview of the authors’ methodology to perform evaluations with two such assessment procedures, namely the P-58 guidelines and the REDi Rating System. P-58, produced by the Federal Emergency Management Agency (FEMA) in the United States, aims to facilitate risk assessment and decision-making by quantifying earthquake ground shaking, structural demands, component damage and resulting consequences in a logical framework. The REDi framework, developed by the engineering firm ARUP, aids stakeholders in implementing resilience-based earthquake design. Preliminary results from the evaluations are presented. These have the potential to provide insights on the ability of the assessment procedures to predict impacts using “real-world” data. However, further work remains to critically analyse these results and to broaden the scope of buildings studied and of impacts predicted.
As a result of the Canterbury earthquakes, over 60% of the concrete buildings in the Christchurch Central Business District have been demolished. This experience has highlighted the need to provide guidance on the residual capacity and repairability of earthquake-damaged concrete buildings. Experience from 2010 Chile indicates that it is possible to repair severely damaged concrete elements (see photo at right), although limited testing has been performed on such repaired components. The first phase of this project is focused on the performance of two lightly-reinforced concrete walls that are being repaired and re-tested after damage sustained during previous testing.
This poster presents preliminary results of ongoing experimental campaigns at the Universities of Auckland and Canterbury, aiming at investigating the seismic residual capacity of damaged reinforced concrete plastic hinges, as well as the effectiveness of epoxy injection techniques for restoring their stiffness, energy dissipation, and deformation capacity characteristics. This work is part of wider research project which started in 2012 at the University of Canterbury entitled “Residual Capacity and Repairing Options for Reinforced Concrete Buildings”, funded by the Natural Hazards Research Platform (NHRP). This research project aims at gaining a better understanding and providing the main end-users and stakeholders (practitioner engineers, owners, local and government authorities, insurers, and regulatory agencies) with comprehensive evidence-based information and practical guidelines to assess the residual capacity of damaged reinforced concrete buildings, as well as to evaluate the feasibility of repairing and thus support their delicate decision-making process of repair vs. demolition or replacement.
The Canterbury earthquakes resulted in numerous changes to the waterways of Ōtautahi Christchurch. These included bank destabilisation, liquefaction effects, changes in bed levels, and associated effects on flow regimes and inundation levels. This study set out to determine if these effects had altered the location and pattern of sites utilised by īnanga (Galaxias maculatus) for spawning, which are typically restricted to very specific locations in upper estuarine areas. Extensive surveys were carried out in the Heathcote/Ōpāwaho and Avon/Ōtākaro catchments over the four peak months of the 2015 spawning season. New spawning sites were found in both rivers and analysis against pre-earthquake records identified that other significant changes have occurred. Major changes include the finding of many new spawning sites in the Heathcote/Ōpāwaho catchment. Sites now occur up to 1.5km further downstream than the previously reported limit and include the first records of spawning below the Woolston Cut. Spawning sites in the Avon/Ōtākaro catchment also occur in new locations. In the mainstem, sites now occur both upstream and downstream of all previously reported locations. A concentrated area of spawning was identified in Lake Kate Sheppard at a distinctly different location versus pre-quake records, and no spawning was found on the western shores. Spawning was also recorded for the first time in Anzac Creek, a nearby waterway connected to Lake Kate Sheppard via a series of culverts.
We present ground motion simulations of the Porters Pass (PP) fault in the Canterbury region of New Zealand; a major active source near Christchurch city. The active segment of the PP fault has an inferred length of 82 km and a mostly strike-slip sense of movement. The PP fault slip makes up approximately 10% of the total 37 mm/yr margin-parallel plate motion and also comprises a significant proportion of the total strain budget in regional tectonics. Given that the closest segment of the fault is less than 45 km from Christchurch city, the PP fault is crucial for accurate earthquake hazard assessment for this major population centre. We have employed the hybrid simulation methodology of Graves and Pitarka (2010, 2015), which combines low (f<1 Hz) and high (f>1 Hz) frequencies into a broadband spectrum. We have used validations from three moderate magnitude events (𝑀𝑤4.6 Sept 04, 2010; 𝑀𝑤4.6 Nov 06, 2010; 𝑀𝑤4.9 Apr 29, 2011) to build confidence for the 𝑀𝑤 > 7 PP simulations. Thus far, our simulations include multiple rupture scenarios which test the impacts of hypocentre location and the finite-fault stochastic rupture representation of the source itself. In particular, we have identified the need to use location-specific 1D 𝑉𝑠/𝑉𝑝 models for the high frequency part of the simulations to better match observations.
Recycling is often employed as part of a disaster waste management system. However, the feasibility, method and effectiveness of recycling varies between disaster events. This qualitative study is based on literature reviews, expert interviews and active participatory research of five international disaster events in developed countries (2009 Victorian Bushfires, Australia; 2009 L’Aquila earthquake, Italy; 2005 Hurricane Katrina, United States; 2010 and 2011 Canterbury earthquakes, New Zealand; 2011 Great East Japan earthquake) to answer three questions: What are the main factors that affect the feasibility of recycling post-disaster? When is on-site or off-site separation more effective? What management approaches improve recycling effectiveness? Seven disaster-specific factors need to be assessed to determine the feasibility of disaster waste recycling programmes: volume of waste; degree of mixing of waste; human and environmental health hazards; areal extent of the waste; community priorities; funding mechanisms; and existing and disaster-specific regulations. The appropriateness of on or off-site waste separation depends on four factors: time constraints; resource availability; degree of mixing of waste and human and public health hazards. Successful recycling programmes require good management including clear and well enforced policies (through good contracts or regulations) and pre-event planning. Further research into post-disaster recycling markets, funding mechanisms and recycling in developing countries is recommended.
A video of Hon. Nicky Wagner, Associate Minister for Canterbury Earthquake Recovery, Hon. Lianne Dalziel, Mayor of Christchurch, and Peter Townsend, CEO of the Canterbury Employers' Chamber of Commerce, responding to questions from the floor during a panel at the 2016 Seismics in the City Conference. The panel has three themes:A City on the Move: Collaboration and Regeneration: "'Christchurch is now moving rapidly from the recovery phase into a regeneration stage with Central and Local Government working with the wider community, including the business community to ensure we get optimal outcomes for greater Christchurch' (CECC)."Looking Back: Remembering and Learning: "What are the milestones? What are the millstones? What have we learnt? What have we applied?"Looking Forward: Visioning and Building: "What do we aspire to? What are the roadblocks? What is the way forward?"
Five years on from the Canterbury Earthquakes there is concern over a group of so-called forgotten victims - adolescent boys. Anti violence group Aviva say they have seen a rise in violent behaviour from this group. Elaine Lacey from Aviva joins me
Following the 22nd February 2011, Mw 6.2 earthquake located along a previously unknown fault beneath the Port Hills of Christchurch, surface cracking was identified in contour parallel locations within fill material at Quarry Road on the lower slopes of Mount Pleasant. GNS Science, in the role of advisor to the Christchurch City Council, concluded that these cracks were a part of a potential rotational mass movement (named zone 11A) within the fill and airfall loess material present. However, a lack of field evidence for slope instability and an absence of laboratory geotechnical data on which slope stability analysis was based, suggested this conclusion is potentially incorrect. It was hypothesised that ground cracking was in fact due to earthquake shaking, and not mass movement within the slope, thus forming the basis of this study. Three soil units were identified during surface and subsurface investigations at Quarry Road: fill derived from quarry operations in the adjacent St. Andrews Quarry (between 1893 and 1913), a buried topsoil, and underlying in-situ airfall loess. The fill material was identified by the presence of organic-rich topsoil “clods” that were irregular in both size (∼10 – 200 mm) and shape, with variable thicknesses of 1 – 10 m. Maximum thickness, as indicated by drill holes and geophysical survey lines, was identified below 6 Quarry Road and 7 The Brae where it is thought to infill a pre-existing gully formed in the underlying airfall loess. Bearing strength of the fill consistently exceeded 300 kPa ultimate below ∼500 mm depth. The buried topsoil was 200 – 300 mm thick, and normally displayed a lower bearing strength when encountered, but not below 300 kPa ultimate (3 – 11 blows per 100mm or ≥100 kPa allowable). In-situ airfall loess stood vertically in outcrop due to its characteristic high dry strength and also showed Scala penetrometer values of 6 – 20+ blows per 100 mm (450 – ≥1000 kPa ultimate). All soils were described as being moist to dry during subsurface investigations, with no groundwater table identified during any investigation into volcanic bedrock. In-situ moisture contents were established using bulk disturbed samples from hand augers and test pitting. Average moisture contents were low at 9% within the fill, 11 % within the buried topsoil, and 8% within the airfall loess: all were below the associated average plastic limit of 17, 15, and 16, respectively, determined during Atterberg limit analysis. Particle size distributions, identified using the sieve and pipette method, were similar between the three soil units with 11 – 20 % clay, 62 – 78 % silt, and 11 – 20 % fine sand. Using these results and the NZGS soil classification, the loess derived fill and in-situ airfall loess are termed SILT with some clay and sand, and the buried topsoil is SILT with minor clay and sand. Dispersivity of the units was found using the Emerson crumb test, which established that the fill can be non- to completely dispersive (score 0 – 4). The buried topsoil was always non-dispersive (score 0), and airfall loess completely dispersive (score 4). Values for cohesion (c) and internal friction angle (φ) of the three soil units were established using the direct shear box at field moisture contents. Results showed all soil units had high shear strengths at the moisture contents tested (c = 18 – 24 kPa and φ = 42 – 50°), with samples behaving in a brittle fashion. Moisture content was artificially increased to 16% within the buried topsoil, which reduced the shear strength (c = 10 kPa, φ = 18°) and allowed it to behave plastically. Observational information indicating stability at Quarry Road included: shallow, discontinuous, cracks that do not display vertical offset; no scarp features or compressional zones typical of landsliding; no tilted or deformed structures; no movement in inclinometers; no basal shear zone identified in logged core to 20 m depth; low field moisture contents; no groundwater table; and high soil strength using Scala penetrometers. Limit equilibrium analysis of the slope was conducted using Rocscience software Slide 5.0 to verify the slope stability identified by observational methods. Friction, cohesion, and density values determined during laboratory were input into the two slope models investigated. Results gave minimum static factor of safety values for translational (along buried topsoil) and rotational (in the fill) slides of 2.4 – 4.2. Sensitivity of the slope to reduced shear strength parameters was analysed using c = 10 kPa and φ = 18° for the translational buried topsoil plane, and a cohesion of 0 kPa within the fill for the rotational plane. The only situation that gave a factor of safety <1.0 was in nonengineered fill at 0.5 m depth. Pseudostatic analysis based on previous peak ground acceleration (PGA) values for the Canterbury Earthquake Sequence, and predicted PGAs for future Alpine Fault and Hope Fault earthquakes established minimum factor of safety values between 1.2 and 3.3. Yield acceleration PGAs were computed to be between 0.8g and 1.6g. Based on all information gathered, the cracking at Quarry Road is considered to be shallow deformation in response to earthquake shaking, and not due to deep-seated landsliding. It is recommended that the currently bare site be managed by smoothing the land, installing contour drainage, and bioremediation of the surface soils to reduce surface water infiltration and runoff. Extensive earthworks, including removal of the fill, are considered unnecessary. Any future replacement of housing would be subject to site-specific investigations, and careful foundation design based on those results.
A section of retaining wall that tilted in the Christchurch 2011 earthquake. At the Edmunds Band Rotunda sight. Still not repaired,
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The 2015 New Zealand strong-motion database provides a wealth of new strong motion data for engineering applications. An important component of this database is the compilation of new site metadata, describing the soil conditions and site response at GeoNet strong motion stations. We have assessed and compiled four key site parameters for the ~460 GeoNet stations that recorded significant historical ground motions. Parameters include: site classification (NZS1170.5), Vs30, fundamental site period (Tsite) and depth to bedrock (Z1.0, i.e. depth to material with Vs > 1000 m/s). In addition, we have assigned a quality estimate (Quality 1 – 3) to these parameters to provide a qualitative estimate of the uncertainty. New highquality Tsite estimates have largely been obtained from newly available HVSR amplification curves and spectral ratios from inversion of regional strong motion data that has been reconciled with available geological information. Good quality Vs30 estimates, typically in urban centres, have also been incorporated following recent studies. Where site-specific measurements of Vs30 are not available, Vs30 is estimated based on surface geology following national Vs30 maps. New Z1.0 values have been provided from 3D subsurface models for Canterbury and Wellington. This database will be used in efforts to guide development and testing of new and existing ground motion prediction models in New Zealand. In particular, it will allow reexamination of the most important site parameters that control and predict site response in a New Zealand setting. Furthermore, it can be used to provide information about suitable rock reference sites for seismological research, and as a guide to site-specific references in the literature. We discuss compilation of the database, preliminary insights so far, and future directions.
A video of a presentation by Hon. Nicky Wagner, Associate Minister for Canterbury Earthquake Recovery, during a panel at the 2016 Seismics in the City Conference. The panel has three themes:A City on the Move: Collaboration and Regeneration: "'Christchurch is now moving rapidly from the recovery phase into a regeneration stage with Central and Local Government working with the wider community, including the business community to ensure we get optimal outcomes for greater Christchurch' (CECC)."Looking Back: Remembering and Learning: "What are the milestones? What are the millstones? What have we learnt? What have we applied?"Looking Forward: Visioning and Building: "What do we aspire to? What are the roadblocks? What is the way forward?"