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.
Commemorates 1 year after the Christchurch Earthquake. In the Press newspaper section of the Fairfax New Zealand Stuff.co.nz news site.
Damaged buildings and empty demolition sites. The building on the left has had tarpaulins placed on it to prevent weather damage to the inside of the building.
A cordon check point on Durham Street. The demolition site was a building that housed Laycock Collision Repairs. The Christchurch Casino can be seen in the background.
A photograph of three excavators clearing the rubble from the site of the demolished Wood's Mill grain silo on Wise Street.
A photograph of an excavator clearing the rubble from the site of the demolished Wood's Mill grain silo of Wise Street.
A photograph of an excavator clearing the rubble from the site of the demolished Wood's Mill grain silo of Wise Street.
Part of the Harvey Norman Centre, the one storey extension previously housing Vast Furniture and Freedom Interiors, has been demolished. Various excavators can be seen on site.
Detail of building rubble, road cones and bits of furniture that have been left in an empty site on the corner of Armagh and Durham Street.
Part of the Harvey Norman Centre, the one storey extension previously housing Vast Furniture and Freedom Interiors, has been demolished. Various excavators can be seen on site.
Part of the Harvey Norman Centre, the one storey extension previously housing Vast Furniture and Freedom Interiors, has been demolished. Various excavators can be seen on site.
Empty demolition sites on Tuam Street. The Alice in Videoland building can be seen on left with the Wespac building and Holiday Inn in the background.
Part of the Harvey Norman Centre, the one storey extension previously housing Vast Furniture and Freedom Interiors, has been demolished. Various excavators can be seen on site.
Intersection of Colombo and St Asaph Street, where road cones have been placed on the road to divert traffic from a demolition site in the background.
Demolition site of a building, where the wall on the adjoining building has been exposed. In the footpath in front is a road cone with a flower.
A demolition site with the words "No Go" spray painted on a fence that has been mostly demolished. Demolition rubble is still contained within the grounds.
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Page 5 of Section A of the Christchurch Press, published on Saturday 23 February 2013.
A photograph of volunteers standing beside a fence made from wooden pallets, at the site of the Poetica Urban Poetry wall.
A photograph of an excavator clearing rubble from the site of the partially-demolished City Council Civic Offices on Manchester Street.
A photograph of emergency tape cordoning off a wall on the edge of the site of the 'Words of Hope' event.
A photograph of an excavator clearing rubble from the site of the partially-demolished City Council Civic Offices on Manchester Street.
The repair of Christchurch's earthquake damaged arts centre has revealed details hidden from view for forty years including a badminton court and the site of an old swimming pool.
Site is managed on behalf of the Royal Commission of Inquiry into Building Failure Caused by the Canterbury Earthquakes by the Department of Internal Affairs.
Site of the National Party MP for Christchurch Central. Communicates her political activities and parliamentary speeches. Includes updates about Christchurch earthquake recovery and rebuild.
Site of a residents' group formed to advocate and protect the rights of red-zoned home owners in the aftermath of the Canterbury earthquakes.
A photograph of the site of a demolished building on Tuam Street. The NewstalkZB building on Worcester Street can be seen in the distance.
A photograph of an earthquake-damaged building, previously the site of Portobello Antiques on Tuam Street. The second storey wall has collapsed leaving the inside exposed.
Detail of a damaged house in an overgrown site. The windows have been boarded up and some words can be partially read, it says "We will try to...".
Steel reinforcement on the exterior wall, next to it is a vacant site left after the demolition of a building. Outside the fence is an aqua Ford Thunderbird car.