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Images, UC QuakeStudies

Children at the River of Flowers memorial event. The photographer comments, "One year on, Riverside residents gather for a 2 minute silence and to cast flowers in the river. Riverside residents met at the Medway St bridge to commemorate the anniversary of the 22/2/11 quake".

Images, UC QuakeStudies

Flowers float down the Avon River during the River of Flowers memorial event. The photographer comments, "One year on, Riverside residents gather for a 2 minute silence and to cast flowers in the river. Riverside residents met at the Medway St bridge to commemorate the anniversary of the 22/2/11 quake".

Images, UC QuakeStudies

A man with a megaphone talks to gathered residents at the River of Flowers memorial event. The photographer comments, "One year on, Riverside residents gather for a 2 minute silence and to cast flowers in the river. Riverside residents met at the Medway St bridge to commemorate the anniversary of the 22/2/11 quake".

Images, UC QuakeStudies

A minister uses a megaphone to talk to gathered residents at the River of Flowers memorial event. The photographer comments, "One year on, Riverside residents gather for a 2 minute silence and to cast flowers in the river. Riverside residents met at the Medway St bridge to commemorate the anniversary of the 22/2/11 quake".

Images, UC QuakeStudies

Workers on the opposite side of the river stop for the River of Flowers memorial event. The photographer comments, "One year on, Riverside residents gather for a 2 minute silence and to cast flowers in the river. Riverside residents met at the Medway St bridge to commemorate the anniversary of the 22/2/11 quake".

Images, UC QuakeStudies

A minister uses a megaphone to talk to gathered residents at the River of Flowers memorial event. The photographer comments, "One year on, Riverside residents gather for a 2 minute silence and to cast flowers in the river. Riverside residents met at the Medway St bridge to commemorate the anniversary of the 22/2/11 quake".

Images, UC QuakeStudies

Residents and workers observe a two-minute silence at the River of Flowers memorial event. The photographer comments, "One year on, Riverside residents gather for a 2 minute silence and to cast flowers in the river. Riverside residents met at the Medway St bridge to commemorate the anniversary of the 22/2/11 quake".

Images, UC QuakeStudies

A man with a megaphone talks to gathered residents at the River of Flowers memorial event. The photographer comments, "One year on, Riverside residents gather for a 2 minute silence and to cast flowers in the river. Riverside residents met at the Medway St bridge to commemorate the anniversary of the 22/2/11 quake".

Images, UC QuakeStudies

A minister uses a megaphone to talk to gathered residents at the River of Flowers memorial event. The photographer comments, "One year on, Riverside residents gather for a 2 minute silence and to cast flowers in the river. Riverside residents met at the Medway St bridge to commemorate the anniversary of the 22/2/11 quake".

Images, UC QuakeStudies

Workers on the opposite side of the river stop for the River of Flowers memorial event. The photographer comments, "One year on, Riverside residents gather for a 2 minute silence and to cast flowers in the river. Riverside residents met at the Medway St bridge to commemorate the anniversary of the 22/2/11 quake".

Images, UC QuakeStudies

Flowers float under the twisted Medway Street Bridge during the River of Flowers memorial event. The photographer comments, "One year on, Riverside residents gather for a 2 minute silence and to cast flowers in the river. Riverside residents met at the Medway St bridge to commemorate the anniversary of the 22/2/11 quake".

Images, UC QuakeStudies

Flowers float down the Avon River during the River of Flowers memorial event. In the background, residents and workers look on. The photographer comments, "One year on, Riverside residents gather for a 2 minute silence and to cast flowers in the river. Riverside residents met at the Medway St bridge to commemorate the anniversary of the 22/2/11 quake".

Images, UC QuakeStudies

A dragon boat is rowed along the river during the River of Flowers memorial event. In the background, workers look on. The photographer comments, "One year on, Riverside residents gather for a 2 minute silence and to cast flowers in the river. Riverside residents met at the Medway St bridge to commemorate the anniversary of the 22/2/11 quake".

Images, UC QuakeStudies

Flowers float down the Avon River during the River of Flowers memorial event. In the background, residents and workers look on. The photographer comments, "One year on, Riverside residents gather for a 2 minute silence and to cast flowers in the river. Riverside residents met at the Medway St bridge to commemorate the anniversary of the 22/2/11 quake".

Images, UC QuakeStudies

Flowers float down the Avon River during the River of Flowers memorial event. In the background, residents and workers look on. The photographer comments, "One year on, Riverside residents gather for a 2 minute silence and to cast flowers in the river. Riverside residents met at the Medway St bridge to commemorate the anniversary of the 22/2/11 quake".

Images, UC QuakeStudies

A digitally manipulated image of light sculptures on Gloucester Street during the LuxCity event. The photographer comments, "This was part of the LuxCity event in Christchurch, New Zealand. It was a way of creating a city of lights on the sites of demolished buildings in the earthquake devastated red zone. 350 architecture and design students from all around New Zealand created and constructed 16 pop up spaces".

Images, UC QuakeStudies

A woman with a megaphone speaks to gathered residents at the River of Flowers memorial event. In the background, workers look on. The photographer comments, "One year on, Riverside residents gather for a 2 minute silence and to cast flowers in the river. Riverside residents met at the Medway St bridge to commemorate the anniversary of the 22/2/11 quake".

Images, UC QuakeStudies

Residents gathered for the River of Flowers memorial event watch a dragon boat being rowed along the river. In the background, workers look on. The photographer comments, "One year on, Riverside residents gather for a 2 minute silence and to cast flowers in the river. Riverside residents met at the Medway St bridge to commemorate the anniversary of the 22/2/11 quake".

Images, UC QuakeStudies

A woman with a megaphone speaks to gathered residents at the River of Flowers memorial event. In the background, workers look on. The photographer comments, "One year on, Riverside residents gather for a 2 minute silence and to cast flowers in the river. Riverside residents met at the Medway St bridge to commemorate the anniversary of the 22/2/11 quake".

Images, UC QuakeStudies

A piper stands beside the twisted Medway Street Bridge during the River of Flowers memorial event. A concrete barrier blocking off the bridge is adorned with flowers. The photographer comments, "One year on, Riverside residents gather for a 2 minute silence and to cast flowers in the river. Riverside residents met at the Medway St bridge to commemorate the anniversary of the 22/2/11 quake".

Images, UC QuakeStudies

Flowers float under the twisted Medway Street Bridge during the River of Flowers memorial event. A colourful cross has been attached to the centre of the bridge. The photographer comments, "One year on, Riverside residents gather for a 2 minute silence and to cast flowers in the river. Riverside residents met at the Medway St bridge to commemorate the anniversary of the 22/2/11 quake".

Research papers, University of Canterbury Library

The November 2016 MW 7.8 Kaikōura Earthquake initiated beneath the North Culverden basin on The Humps fault and propagated north-eastwards, rupturing at least 17 faults along a cumulative length of ~180 km. The geomorphic expression of The Humps Fault across the Emu Plains, along the NW margin of Culverden basin, comprises a series of near-parallel strands separated by up to 3 km across strike. The various strands strike east to east-northeast and have been projected to mainly dip steeply to the south in seismic data (~80°). In this area, the fault predominantly accommodates right-lateral slip, with uplift and subsidence confined to releasing and restraining bends and step-overs at a range of scales. The Kaikōura event ruptured pre-existing fault scarps along the Emu Plains, which had been partly identified prior to the earthquake. Geomorphology and faulting expression of The Humps Fault on The Emu Plains was mapped, along with faulting related structures which did not rupture in the 2016 earthquake. Fault ruptures strands are combined into sections and the kinematic deformation of sections analysed to provide a moment tensor fault plane solution. This fault plane solution is consistent with the regional principal horizontal shortening direction (PHS) of ~115°, similar to seismic focal mechanism solutions of some of the nearby aftershocks of the Kaikōura earthquake, and similar to the adjacent Hope Fault. To constrain the timing of paleoseismic events, a trench was excavated across the fault where it crossed a late Quaternary alluvial fan. Mapping of stratigraphy exposed in the trench walls, and dating of variably deformed strata, constrains the pre-historic earthquake event history at the trench site. The available data provides evidence for at least three paleo-earthquakes within the last 15.1 ka, with a possible fourth (penultimate) event. These events are estimated to have occurred at 7.7-10.3 ka, 10.3-14.8 ka, and one or more events that are older than ~15.1 ka. Some evidence suggests an additional penultimate event between 1850 C.E and 7.7 ka. Time-integrated slip-rates at three locations on the fault are measured using paleo-channels as piercing points. These sites give horizontal slip rates of 0.57 ± 0.1 mm/year, 0.49 ± 0.1 mm/year and one site constrains a minimum of between 0.1 - 0.4 mm/year. Two vertical slip-rates are calculated to be constrained to a maximum of 0.2 ± 0.02 mm/year at one site and between 0.02 and 0.1 mm/year at another site. Prior to this study, The Humps fault had only been partially documented in reconnaissance level mapping in the district, and no previous paleoseismic or slip rate data had been reported. This project has provided a detailed fault zone tectonic geomorphic map and established new slip-rate and paleoseismic data. The results highlight that The Humps fault plays an important role in regional seismicity and in accommodating plate boundary deformation across the North Canterbury region.

Articles, UC QuakeStudies

This report was the first report in the district series, and has a different format to later reports. It includes all natural hazards, not only earthquake hazards. It describes earthquake, flooding, meteorological, landslide and coastal hazards within Hurunui district and gives details of historic events. It includes district-scale (1:250,000) active fault and flood hazard maps. The report describes an earthquake scenario for a magnitude 6.9 earthquake near Cheviot, as well as flooding, meteorological, landslide, coastal erosion, storm surge, and tsunami scenarios. See Object Overview for background and usage information.

Research papers, University of Canterbury Library

Oblique-convergent plate collision between the Pacific and Australian plates across the South Island has resulted in shallow, upper crustal earthquake activity and ground surface deformation. In particular the Porters Pass - Amberley Fault Zone displays a complex hybrid zone of anastomosing dextral strike-slip and thrust/reverse faulting which includes the thrust/reverse Lees Valley Fault Zone and associated basin deformation. There is a knowledge gap with respect to the paleoseismicity of many of the faults in this region including the Lees Valley Fault Zone. This study aimed to investigate the earthquake history of the fault at a selected location and the structural and geomorphic development of the Lees Valley Fault Zone and eastern rangefront. This was investigated through extensive structural and geomorphic mapping, GPS field surveying, vertical aerial photo interpretation, analysis of Digital Elevation Models, paleoseismic trenching and optically stimulated luminescence dating. This thesis used a published model for tectonic geomorphology development of mountain rangefronts to understand the development of Lees Valley. Rangefront geomorphology is investigated through analysis of features such as rangefront sinuosity and faceted spurs and indicates the recently active and episodic nature of the uplifted rangefront. Analysis of fault discontinuity, fault splays, distribution of displacement, fault deformation zone and limited exposure of bedrock provided insight into the complex structure of the fault zone. These observations revealed preserved, earlier rangefronts, abandoned and uplifted within the eastern ranges, indicating a basinward shift in focus of faulting and an imbricate thrust wedge development propagating into the footwall of the fault zone and along the eastern ranges of Lees Valley. Fault scarp deformation analysis indicated multiple events have produced the deformation present preserved by the active fault trace in the northern valley. Vertical deformation along this scarp varied with a maximum of 11.5 m and an average of 5 m. Field mapping revealed fan surfaces of various ages have been offset and deformed, likely during the Holocene, based on expected relative surface ages. Geomorphic and structural mapping highlighted the effect of cross-cutting and inherited structures on the Lees Valley Fault, resulting in a step-over development in the centre of the eastern range-bounding trace. Paleoseismic trenching provided evidence of at least two earthquakes, which were constrained to post 21.6 ± 2.3 ka by optically stimulated luminescence dating. Single event displacements (1.48 ± 0.08 m), surface rupture earthquake magnitudes (Mw 6.7 ± 0.1, with potential to produce ≥ 7.0), and a minimum recurrence interval (3.6 ± 0.3 ka) indicated the Lees Valley Fault is an active structure capable of producing significant earthquake events. Results from this study indicate that the Lees Valley Fault Zone accommodates an important component of the Porters Pass - Amberley Fault Zone deformation and confirms the fault as a source of potentially damaging, peak ground accelerations in the Canterbury region. Remnants of previous rangefronts indicate a thrust wedge development of the Lees Valley Fault Zone and associated ranges that can potentially be used as a model of development for other thrust-fault bounded basins.

Images, UC QuakeStudies

A faded yellow sticker stuck to the window of a house on Avonside Drive. It has been issued by the Christchurch City Council and reads, "Restricted Use. No entry except on essential business. Warning: This building has been damaged and its structural safety is questionable. Enter only at own risk. Subsequent aftershocks or other events may result in increased damage and danger, changing this assessment. Re-inspection may be required. The damage observed from external inspection is as described below." It goes on to set out the conditions for entry to the building and information about the inspector. The sign is so faded that the handwritten information is almost illegible.

Research Papers, Lincoln University

The timing of large Holocene prehistoric earthquakes is determined by dated surface ruptures and landslides at the edge of the Australia-Pacific plate boundary zone in North Canterbury, New Zealand. Collectively, these data indicate two large (M > 7) earthquakes during the last circa 2500 years, within a newly formed zone of hybrid strike-slip and thrust faulting herein described as the Porter's Pass-to-Amberley Fault Zone (PPAFZ). Two earlier events during the Holocene are also recognized, but the data prior to 2500 years are presumed to be incomplete. A return period of 1300–2000 years between large earthquakes in the PPAFZ is consistent with a late Holocene slip rate of 3–4 mm/yr if each displacement is in the range 4–8 m. Historical seismicity in the PPAFZ is characterized by frequent small and moderate magnitude earthquakes and a seismicity rate that is identical to a region surrounding the structurally mature Hope fault of the Marlborough Fault System farther north. This is despite an order-of-magnitude difference in slip rate between the respective fault zones and considerable differences in the recurrence rate of large earthquakes. The magnitude-frequency distribution in the Hope fault region is in accord with the characteristic earthquake model, whereas the rate of large earthquakes in the PPAFZ is approximated (but over predicted) by the Gutenberg-Richter model. The comparison of these two fault zones demonstrates the importance of the structural maturity of the fault zone in relation to seismicity rates inferred from recent, historical, and paleoseismic data.

Research papers, University of Canterbury Library

The Porter's Pass-Amberley Fault Zone (PPAFZ) is a complex zone of anastomosing faults and folds bounding the south-eastern edge of the transition from subducting Pacific Plate to continental collision on the Australia Plate boundary. This study combines mapping of a 2000 km2 zone from the Southern Alps northeast to the coast near Amberley, 40 km north of metropolitan Christchurch, with an analysis of seismicity and a revision of regional seismic hazard. Three structural styles: 1) a western strike-slip, and 2) a more easterly thrust and reverse domain, pass into 3) a northwest verging fold belt on the northern Canterbury Plains, reflecting the structural levels exposed and the evolving west to east propagation. Basal remnants of a Late Cretaceous-Cenozoic, largely marine sedimentary cover sequence are preserved as outliers that unconformably overlie Mesozoic basement (greywacke and argillite of the Torlesse terrain) in the mountains of the PPAFZ and are underlain by a deeply leached zone which is widely preserved. Structure contouring of the unconformity surface indicates maximum, differential uplift of c.2600 m in the southwest, decreasing to c.1200 m in the coastal fold belt to the northeast. Much lower rates (or reversal) of uplift are evident a few kilometres southeast of the PPAFZ range-front escarpment. The youngest elements of the cover sequence are basement-derived conglomerates of Plio-Pleistocene age preserved on the SE margin. The source is more distant than the intervening mountains of the PPAFZ, probably from the Southern Alps, to the west and northwest. The absence of another regional unconformity on Mesozoic basement, older than Pleistocene, indicates that this uplift is post-Pliocene. Late Pleistocene(<100 kyr) differential uplift rates of c.0.5-2.7 m/kyr from uplifted marine terraces at the east coast, and rates of 2.5-3.3 m/kyr for tectonically-induced river-down cutting further west, suggest that uplift commenced locally during the last 1 Ma, and possibly within the last 0.5 Ma, if average rates are assumed to be uniform over time. Analysis of seismicity, recorded during a 10 week regional survey of micro earthquakes in 1990, identified two seismic zones beneath North Canterbury: 1) a sub-horizontal zone of activity restricted to the upper crust (≤12 km); and 2) a seismic zone in the lower crust (below a ceiling of ≤17 km), that broadens vertically to the north and northwest to a depth of c.40 km, with a bottom edge which dips 10°N and 15°NW, respectively. No events were recorded at depths between 12 km and 17 km, which is interpreted as a relatively aseismic, mid-crustal ductile layer. Marked differences (up to 60°) in the trend of strain axes for events above and below the inferred ductile layer are observed only north of the PPAFZ. A fundamental, north-to-south increase in the Wave-length of major geological structures occurs across the PPAFZ, and is interpreted as evidence that the upper crust beneath the Canterbury Plains is coupled to the lower crust, whereas the upper crust further north is not. Most of the recorded micro earthquakes <12 km deep beneath the PPAFZ have strike-slip mechanisms. It is probable that faults splay upward into the thrusts and folds at the surface as an evolving transpression zone in response to deep shear in basement. There have been no historic surface ruptures of the PPAFZ, but the zone has been characterised historically by frequent small earthquakes. Paleoseismic data (dated landslides and surface ruptures) compiled in this study, indicate a return period of 1500-1900 years between the last two M>7-7.5 earthquakes, and 500-700 years have elapsed since the last. The magnitudes of these events are estimated at c.M7.5, which represents a probable maximum magnitude for the PPAFZ. There are insufficient data to determine whether or not the frequency of large earthquakes conforms to a recognised model of behaviour, but comparison of the paleoseismic data with the historic record of smaller earthquakes, suggests that the magnitudes of the largest earthquakes in this zone are not exponentially distributed. A seismicity model for the PPAFZ (Elder et al., 1991) is reviewed, and a b-value of 1.0 is found to be consistent with the newly acquired paleoseismic data. This b-value reduces the predicted frequency of large earthquakes (M≥7.0) in this zone by a factor of 3.5, while retaining a conservative margin that allows for temporal variations in the frequency of large events and the possibility that the geological database is incomplete, suggesting grounds for revising the hazard model for Christchurch.

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.