Photograph captioned by BeckerFraserPhotos, "Slumping near the Avon River on Avonside Drive".
Photograph captioned by BeckerFraserPhotos, "Extensive slumping and cracking near where Horseshoe Lake joins up with the Avon River".
A gap between the house and the foundations along Avonside drive caused when the house was lifted during the 4 September earthquake.
Large cracks on Fitzgerald Avenue, closing one side of the road. Road cones have been used to indicate two lanes on the other side.
A house on Avonside Drive showing large cracks in its foundations and siding. A crack is also visible in the earth of the front lawn.
An abandoned house on Avonside Drive. A red sign taped to the window states that the house is "Unsafe" to enter.
Photograph captioned by BeckerFraserPhotos, "Extensive slumping and cracking near where Horseshoe Lake joins up with the Avon River".
A photograph of the earthquake damage to the curb of a street in Christchurch. The curb has cracked in two places and slumped, exposing the earth beneath the grass turf.
Photograph captioned by BeckerFraserPhotos, "The Avon River is at this point on Avonside Drive 10 km from the estuary. At high tide the river now overflows its banks showing that the ground has sunk by about 40 cm".
A photograph captioned by BeckerFraserPhotos, "A section of Avonside Drive shows how the infrastructure is no longer maintained to the same level, with regard to roading, sewage and water services. The houses behind show the crazy angles that the earth movement has left them at".
A photograph of road works on a residential street in Christchurch. Two workers in high-visibility vests can be seen, one setting up road cones. A digger is sitting on a pile of dug up gravel and earth. Cordon fences have been placed around the site. In the distance, a dump truck can be seen.
This paper presents on-going challenges in the present paradigm shift of earthquakeinduced ground motion prediction from empirical to physics-based simulation methods. The 2010-2011 Canterbury and 2016 Kaikoura earthquakes are used to illustrate the predictive potential of the different methods. On-going efforts on simulation validation and theoretical developments are then presented, as well as the demands associated with the need for explicit consideration of modelling uncertainties. Finally, discussion is also given to the tools and databases needed for the efficient utilization of simulated ground motions both in specific engineering projects as well as for near-real-time impact assessment.
An aerial photograph captioned by BeckerFraserPhotos, "Victoria Square is at the centre of this picture with its green lawns and trees. The bare patch of earth in front s the demolition sites of the Allan McLean building, the Oxford on Avon, and Plunket House. The contract to demolish the Crowne Plaza Hotel has been let, while the fate of the Town Hall is still undecided. The Convention Centre is coming down. On the very bottom, slightly to the right is the Medlab building which is also to be demolished. In the bottom left corner is the PWC building which is also to be demolished".
Hybrid broadband simulation methods typically compute high-frequency portion of ground-motions using a simplified-physics approach (commonly known as “stochastic method”) using the same 1D velocity profile, anelastic attenuation profile and site-attenuation (κ0) value for all sites. However, these parameters relating to Earth structure are known to vary spatially. In this study we modify this conventional approach for high-frequency ground-shaking by using site-specific input parameters (referred to as “site-specific”) and analyze improvements over using same parameters for all sites (referred to as “generic”). First, we theoretically understand how different 1D velocity profiles, anelastic attenuation profiles and site-attenuation (κ0) values affects the Fourier Acceleration Spectrum (FAS). Then, we apply site-specific method to simulate 10 events from the 2010-2011 Canterbury earthquake sequence to assess performance against the generic approach in predicting recorded ground-motions. Our initial results suggest that the site-specific method yields a lower simulation standard deviation than generic case.
A tribute taped to a window of a house on Tasman Place. The tribute reads, "Our red zoned house. When we bought you years ago, you looked a bit tired and sad, but overall you weren't too bad. We spruced you up with paint and love and asked for a blessing from above. The years went by, family and friends celebrations under your roof, your 'veggie' garden gave us kai. We felt safe within your wall, then one dreadful September night, the shaking earth made you fall. You tried with all your groaning might to keep us from harm. Because you were strongly built we held onto the door, while a wave of terror buckled the floor and outside the garden flooded with silt. Now you are near the end, sunken walls and windows bend. We say goodbye today and let you go, Our spirit and heart feels low. You are more than just mortar and brick. For us you were a gift, a safe haven where we once lived".
We examined the stratigraphy of alluvial fans formed at the steep range front of the Southern Alps at Te Taho, on the north bank of the Whataroa River in central West Coast, South Island, New Zealand. The range front coincides with the Alpine Fault, an Australian-Pacific plate boundary fault, which produces regular earthquakes. Our study of range front fans revealed aggradation at 100- to 300-year intervals. Radiocarbon ages and soil residence times (SRTs) estimated by a quantitative profile development index allowed us to elucidate the characteristics of four episodes of aggradation since 1000 CE. We postulate a repeating mode of fan behaviour (fan response cycle [FRC]) linked to earthquake cycles via earthquake-triggered landslides. FRCs are characterised by short response time (aggradation followed by incision) and a long phase when channels are entrenched and fan surfaces are stable (persistence time). Currently, the Te Taho and Whataroa River fans are in the latter phase. The four episodes of fan building we determined from an OxCal sequence model correlate to Alpine Fault earthquakes (or other subsidiary events) and support prior landscape evolution studies indicating ≥M7.5 earthquakes as the main driver of episodic sedimentation. Our findings are consistent with other historic non-earthquake events on the West Coast but indicate faster responses than other earthquake sites in New Zealand and elsewhere where rainfall and stream gradients (the basis for stream power) are lower. Judging from the thickness of fan deposits and the short response times, we conclude that pastoral farming (current land-use) on the fans and probably across much of the Whataroa River fan would be impossible for several decades after a major earthquake. The sustainability of regional tourism and agriculture is at risk, more so because of the vulnerability of the single through road in the region (State Highway 6).