A pothole in a road surface, showing tyre marks where a vehicle has driven through the hole. The photographer comments, "After the earthquake in Christchurch in February 2011 burst underground pipes and liquefaction caused unseen hollows under the road surfaces. Occasionally after all the rest have been exposed by traffic someone would find 'discover' a new one".
Surface rupture of the previously unrecognised Greendale Fault extended west-east for ~30 km across alluvial plains west of Christchurch, New Zealand, during the Mw 7.1 Darfield (Canterbury) earthquake of September 2010. Surface rupture displacement was predominantly dextral strike-slip, averaging ~2.5 m, with maxima of ~5 m. Vertical displacement was generally less than 0.75 m. The surface rupture deformation zone ranged in width from ~30 to 300 m, and comprised discrete shears, localised bulges and, primarily, horizontal dextral flexure. About a dozen buildings, mainly single-storey houses and farm sheds, were affected by surface rupture, but none collapsed, largely because most of the buildings were relatively flexible and resilient timber-framed structures and also because deformation was distributed over a relatively wide zone. There were, however, notable differences in the respective performances of the buildings. Houses with only lightly-reinforced concrete slab foundations suffered moderate to severe structural and non-structural damage. Three other buildings performed more favourably: one had a robust concrete slab foundation, another had a shallow-seated pile foundation that isolated ground deformation from the superstructure, and the third had a structural system that enabled the house to tilt and rotate as a rigid body. Roads, power lines, underground pipes, and fences were also deformed by surface fault rupture and suffered damage commensurate with the type of feature, its orientation to the fault, and the amount, sense and width of surface rupture deformation.
A photograph of an access hole in the middle of a road in the Horseshoe Lake District which has raised above the surface of the road. White spray-paint and a road cone have been used to alert drivers of the uneven surface.
This paper provides a photographic tour of the ground-surface rupture features of the Greendale Fault, formed during the 4th September 2010 Darfield Earthquake. The fault, previously unknown, produced at least 29.5 km of strike-slip surface deformation of right-lateral (dextral) sense. Deformation, spread over a zone between 30 and 300 m wide, consisted mostly of horizontal flexure with subsidiary discrete shears, the latter only prominent where overall displacement across the zone exceeded about 1.5 m. A remarkable feature of this event was its location in an intensively farmed landscape, where a multitude of straight markers, such as fences, roads and ditches, allowed precise measurements of offsets, and permitted well-defined limits to be placed on the length and widths of the surface rupture deformation.
Spray paint on the footpath to mark out the uneven surface.
Damage to the asphalt surface of a car park in Kaiapoi.
A photograph of the undulating surface of Main Road in Mt Pleasant.
A photograph of cracks and liquefaction in the surface of Hagley Park.
A photograph of the undulating surface of Main Road in Mt Pleasant.
A photograph of cracks and liquefaction in the surface of Hagley Park.
A street sign and road cone near the Avon River saying "Uneven Surface".
Spray painted marks on the footpath outside the Casino indicating cracks and uneven surfaces.
A damaged house with cracks down the wall sits on an uneven surface.
The previously unknown Greendale Fault ruptured to the ground surface, causing up to 5 metres horizontal and 1 metre vertical permanent offset of the ground, during the September 2010 Darfield (Canterbury) earthquake. Environment Canterbury commissioned GNS Science, with help from the University of Canterbury, to define a fault avoidance zone and to estimate the fault recurrence interval. There is little evidence for past movement on the fault in the past 16,000 years. However, because of the uncertainties involved, a conservative approach was taken and the fault has been categorised as a Recurrence Interval Class IV fault (a recurrence interval of between 5,000 and 10,000 years). A PhD study by a University of Canterbury student will work towards refining the Recurrence Interval Class over the next three years. Taking a risk-based approach, the Ministry for the Environment Active Fault Guidelines recommend that normal residential development be allowed within the fault avoidance zone for faults of this Recurrence Interval Class, but recommends restrictions for larger community buildings or facilities with post-disaster functions. The report is assisting Selwyn District Council in granting consents for rebuilding houses on or near the Greendale Fault that were damaged by permanent distortion of the ground due to the fault rupture in the September 2010 earthquake. The report provides specific recommendations for building on or close to the Greendale Fault, which are being implemented by Selwyn District Council. See Object Overview for background and usage information.
Two road cones mark out an uneven surface on the road. The hole is filled with water.
Workers repairing power lines on Settlers Crescent in Ferrymead. Liquefaction silt can be seen on the road surface.
A view down the Avon River in the city centre. A street sign marks out an uneven surface further down the street.
A damaged footpath in the Christchurch Botanic Gardens. Two orange cones have been placed on the damaged concrete to warn people of the uneven surface.
Damage to the footpath on Hereford Street. Yellow zigzags have been spray painted on the round to warn people of the irregular surface.
A man walks across his cracked and liquefaction-covered lawn in Richmond. The photographer comments, "Andy Corbin checks liquefaction and surface water in his lawn".
Children play on the netball court at Lyttelton Main primary school. The surface of the court has been warped by the earthquakes.
A view over the Avon River towards Oxford Terrace where the road is badly cracked and slumping towards the river. Road cones mark the uneven surface.
A view down Robson Avenue in Avonside showing damage to the road surface and the footpath that has resulted from the 4 September 2010 earthquake.
A view down Robson Avenue in Avonside showing damage to the road surface and the footpath that has resulted from the 4 September 2010 earthquake.
A road roller parked on the side of Banks Avenue. The street is under repair and has a gravel surface. The photographer comments, "Road works in Banks Avenue".
A photograph captioned by BeckerFraserPhotos, "A view looking along Poplar Lane. Two weeks earlier the surface of the lane was clear".
Damage to River Road in Richmond. The road surface is badly cracked and slumped, and liquefaction silt covers part of the road. The photographer comments, "Lateral spreading cracks in River Rd".
A photograph captioned by BeckerFraserPhotos, "The road surface of the Colombo Street bridge over the River Avon, showing the effect of compression".
Damage to River Road in Richmond. The road surface is badly cracked and slumped, and liquefaction silt covers part of the road. The photographer comments, "Liquefaction in River Rd. This is minor compared to many streets in town".
A portaloo sits outside a house on River Road. The road is under repair, and the tarmac has been removed leaving a gravel surface. The photographer comments, "Our old house was given a portaloo; I'm not sure why".