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Research papers, University of Canterbury Library

Geomorphic, structural and chronological data are used to establish the late Quaternary paleoseismicity of the active dextral-oblique Northern Esk Fault in North Canterbury, New Zealand. Detailed field mapping of the preserved c. 35 km of surface traces between the Hurunui River and Ashley Head reveals variations in strike ranging from 005° to 057°. Along with kinematic data collected from fault plane striae and offset geomorphic markers along the length of the fault these variations are used to distinguish six structural subsections of the main trace, four dextral-reverse and two dextral-normal. Displacements of geomorphic markers such as minor streams and ridges are measured using differential GPS and rangefinder equipment to reveal lateral offsets ranging from 3.4 to 23.7 m and vertical offsets ranging from < 1 to 13.5 m. Characteristic single event displacements of c. 5 m and c. 2 m have been calculated for strike-slip and reverse sections respectively. The use of fault scaling relationships reveals an anomalously high displacement to surface rupture length ratio when compared to global data sets. Fault scaling relationships based on width limited ruptures and magnitude probabilities from point measurements of displacement imply earthquake magnitudes of Mw 7.0 to 7.5. Optically Stimulated Luminescence (OSL) ages from displaced Holocene alluvial terraces at the northern extent of the active trace along with OSL and radiocarbon samples of the central sections constrain the timing of the last two surface rupturing events (11.15 ±1.65 and 3.5 ± 2.8 ka) and suggest a recurrence interval of c. 5612 ± 445 years and late Quaternary reverse and dextral slip rates of c. 0.31 mm/yr and 0.82 mm/yr respectively. The results of this study show that the Northern Esk Fault accommodates an important component of the c. 0.7 – 2 mm/yr of unresolved strain across the plate boundary within the North Canterbury region and affirm the Esk Fault as a source of potentially damaging ground shaking in the Canterbury region.

Research papers, University of Canterbury Library

Surface rupture and slip from the Mw 7.8 2016 Kaikōura Earthquake have been mapped in the region between the Leader and Charwell rivers using field mapping and LiDAR data. The eastern Humps, north Leader and Conway-Charwell faults ruptured the ground surface in the study area. The E-NE striking ‘The Humps’ Fault runs along the base of the Mt Stewart range front, appears to dip steeply NW and intersects the NNW-NNE Leader Fault which itself terminates northwards at the NE striking Conway-Charwell Fault. The eastern Humps Fault is up to the NW and accommodates oblique slip with reverse and right lateral displacement. Net slip on ‘The Humps’ Fault is ≤4 m and produced ≤4 m uplift of the Mt Stewart range during the earthquake. The Leader Fault strikes NNW-NNE with dips ranging from ~10° west to 80° east and accommodated ≤4 m net slip comprising left-lateral and up-to-the-west vertical displacement. Like the Humps west of the study area, surface-rupture of the Leader Fault occurred on multiple strands. The complexity of rupture on the Leader Fault is in part due to the occurrence of bedding-parallel slip within the Cretaceous-Cenozoic sequence. Although the Mt Stewart range front is bounded by ‘The Humps’ Fault, in the study area neither this fault nor the Leader Fault were known to have been active before the earthquake. Fieldwork and trenching investigations are ongoing to characterise the geometry, kinematics and paleoseismic history of the mapped active faults.

Research papers, University of Canterbury Library

The Mw 7.8 Kaikōura earthquake ruptured ~200 km at the ground surface across the New Zealand plate boundary zone in the northern South Island. This study was conducted in an area of ~600 km2 in the epicentral region where the faults comprise two main non-coplanar sets that strike E-NE and NNE-NW with mainly steep dips (60о-80°). Analysis of the surface rupture using field and LiDAR data provides new information on the dimensions, geometries and kinematics of these faults which was not previously available from pre-earthquake active faults or bedrock structure. The more northerly striking fault set are sub-parallel to basement bedding and accommodated predominantly left-lateral reverse slip with net slips of ~1 and ~5 m for the Stone Jug and Leader faults, respectively. The E-NE striking Conway-Charwell and The Humps faults accrued right-lateral to oblique reverse with net slips of ~2 and ~3 m, respectively. The faults form a hard-linked system dominated by kinematics consistent with the ~260° trend of the relative plate motion vector and the transpressional structures recorded across the plate boundary in the NE South Island. Interaction and intersection of the main fault sets facilitated propagation of the earthquake and transfer of slip northwards across the plate boundary zone.

Images, Alexander Turnbull Library

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

Images, UC QuakeStudies

Dried liquefaction silt in North New Brighton. The photographer comments, "Here you can see the very fine surface layer of liquefaction starting to shrink, crack and then curl up on itself".

Images, eqnz.chch.2010

One of many disabled carparks outside what used to be one of the great sporting complexes in New Zealand. The Queen Elizabeth II Park complex in north-east Christchurch was built initially for the 1974 Commonwealth Games and was used for track and field and the adjoining pool complex had swimming and diving. It was built on an area that was used...

Images, eqnz.chch.2010

A month after the 1st anniversary of the deadly Christchurch earthquake (22/02/11) a road cone lies on New Brighton Road, alongside the Avon River. Part of the earthquake 1st anniversary remembrance was for people to place flowers in road cones (and there are hundreds of thousands in the city). Many had flowers in them, as this one did. Photo ...

Audio, Radio New Zealand

As Auckland and Northland brace for more atrocious weather, city leaders are calling for funding to repair the city's broken infrastructure to be along the lines of the help given to Christchurch after the quakes. Auckland deputy mayor Desley Simpson says that the damage so far is equivalent to the biggest non earthquake event the country has ever had and should be treated accordingly. The Opportunities Party says the "alliance" model established after the earthquakes, was effective and would work for Auckland's rebuild, because it provides a structure that the Central Government can fund directly. ToP leader Raf Manji was a Christchurch councillor after the quakes and closely involved in the rebuild. He tells Kathryn Ryan it is vital to ensure water and transport infrastructure is repaired quickly and efficiently, especially with a view to future extreme weather events - and there is much to learn from the post-quake rebuild.

Images, UC QuakeStudies

Damage to TJ's Kazbah in New Brighton. The east and north walls and part of the upper floor have collapsed, tipping rubble and the contents of the rooms out onto the street. The photographer comments, "The occupants of the business and rooms all managed to escape alive. A digger was used to make the building safe and then used to sift through the rubble for any surviving belongings. It was a very emotional time for the ex-occupants".

Audio, Radio New Zealand

Nearly two-thirds of MPs have voted in support of a bill that would legalise euthanasia. The Government says it will consider moves to rein in rapidly rising salaries for top public servants. It's been far from smooth sailing for the new government in its first eight weeks in office, but it appears to be largely on track to deliver its hundred day plan. More than a year after North Canterbury's 7.8 magnitude earthquake forced its closure, State Highway 1 north of Kaikoura will re-open to the public on Friday. 

Images, UC QuakeStudies

The north side of the cathedral with its boarded-up windows. Shipping containers have been placed next to the cathedral to protect the street from falling rubble. The Citizens' Memorial stands to the right.