The flooded and silt-laden Avon River seen from River Road in Richmond. The photographer comments, "Avon at high tide, River Rd".
The Avon River in Avonside, seen before the earthquakes. The photographer comments, "Avon River and Avonside Drive, near Robson Ave. Taken approx 317 River Road".
Aftermath of September 4th Earthquake in Canterbury (area covers Christchurch City), NZ. Cracks alongside Avon river.
The flooded and silt-laden Avon River seen from River Road in Richmond. The photographer comments, "Avon at high tide, River Rd, looking towards the Medway St Bridge".
Silt-laden water flows into the Avon River. The photographer comments, "Corner River Rd, Banks Ave, Dallington Tce. Dirty water from Dudley Creek meets the Avon".
Trees alongside the Avon River in Richmond. The river level is high, and the water is grey with silt. One of the trees is leaning towards the river. The photographer comments, "High river levels because of liquefaction in the Avon. Near 373 River Rd, Richmond".
The Avon River in Richmond. The river level is very high, and the water is grey with silt. The photographer comments, "By the corner of Medway St and River Rd. The Avon seems to be very full, with grey silt laden water".
Silt build-up in the Avon River. The photographer comments, "River Rd, Richmond, near Swanns Rd bridge".
The flooded and silt-laden Avon River seen from River Road in Richmond. The photographer comments, "View from River Rd towards the Medway St corner".
The flooded and silt-laden Avon River seen from River Road in Richmond. Across the river, Avonside Drive is lined with portaloos and road cones.
Aftermath of September 4th Earthquake in Christchurch, NZ. Footbridge over Avon river
Flooding on River Road in Richmond. The photographer comments, "Dudley Creek flowing through properties on River Rd, then into the Avon".
Aftermath of September 4th Earthquake in Canterbury, NZ. Footbridge over Avon river, Christchurch
A pathway through trees on the University of Canterbury campus, beside the Avon River. The photographer comments, "Path by the river, University Drive".
The twisted and broken Medway Street bridge, over a flooded and silt-laden Avon River.
Water and liquefaction flows into the Avon River in Richmond. The water level is very high, and the water is cloudy with silt. The photographer comments, "Water from Dudley Creek took a shortcut across the road into the Avon. It doesn't have much of a drop from the road to the river".
Aftermath of September 4th Earthquake in Canterbury, NZ. Damage to road alongside Avon River, Christchurch.
Aftermath of September 4th Earthquake in Canterbury, NZ. Damage to roads alongside Avon river, Christchurch.
Aftermath of September 4th Earthquake in Canterbury, NZ. Damage to roads alongside Avon river, Christchurch City.
A document describing Downer's planned approach for neutralising the high pH of any potential bentonite or grout discharge into the Avon river.
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".
A bicycle stands with its front wheel wedged in a road crack. The photographer comments, "Cracks in the road can be useful - a free bike stand. Corner of North Avon Rd and River Rd".
A warning sign posted on River Road beside the Avon River reads "Health warning, contaminated water. Due to sewage overflows this water is unsafe for human contact and activity and is a public health risk. Please keep all people and pets out of contact with the water and do not cosume and seafood or shellfish collected from this area." The photographer comments, "A bike ride around the CBD. River Rd subsidence".
A damaged wooden footbridge across the Avon River beside University Drive is blocked off with sheets of plywood and danger signs. The photographer comments, "The University restarts its teaching, and the techies in e-learning move out of NZi3. The bridge to the Rec Centre".
Liquefaction-induced lateral spreading during earthquakes poses a significant hazard to the built environment, as observed in Christchurch during the 2010 to 2011 Canterbury Earthquake Sequence (CES). It is critical that geotechnical earthquake engineers are able to adequately predict both the spatial extent of lateral spreads and magnitudes of associated ground movements for design purposes. Published empirical and semi-empirical models for predicting lateral spread displacements have been shown to vary by a factor of <0.5 to >2 from those measured in parts of Christchurch during CES. Comprehensive post- CES lateral spreading studies have clearly indicated that the spatial distribution of the horizontal displacements and extent of lateral spreading along the Avon River in eastern Christchurch were strongly influenced by geologic, stratigraphic and topographic features.
The Canterbury Earthquake Sequence 2010-2011 (CES) induced widespread liquefaction in many parts of Christchurch city. Liquefaction was more commonly observed in the eastern suburbs and along the Avon River where the soils were characterised by thick sandy deposits with a shallow water table. On the other hand, suburbs to the north, west and south of the CBD (e.g. Riccarton, Papanui) exhibited less severe to no liquefaction. These soils were more commonly characterised by inter-layered liquefiable and non-liquefiable deposits. As part of a related large-scale study of the performance of Christchurch soils during the CES, detailed borehole data including CPT, Vs and Vp have been collected for 55 sites in Christchurch. For this subset of Christchurch sites, predictions of liquefaction triggering using the simplified method (Boulanger & Idriss, 2014) indicated that liquefaction was over-predicted for 94% of sites that did not manifest liquefaction during the CES, and under-predicted for 50% of sites that did manifest liquefaction. The focus of this study was to investigate these discrepancies between prediction and observation. To assess if these discrepancies were due to soil-layer interaction and to determine the effect that soil stratification has on the develop-ment of liquefaction and the system response of soil deposits.
Liquefaction-induced lateral spreading during the 2011 Christchurch earthquake in New Zealand was severe and extensive, and data regarding the displacements associated with the lateral spreading provides an excellent opportunity to better understand the factors that influence these movements. Horizontal displacements measured from optical satellite imagery and subsurface data from the New Zealand Geotechnical Database (NZGD) were used to investigate four distinct lateral spread areas along the Avon River in Christchurch. These areas experienced displacements between 0.5 and 2 m, with the inland extent of displacement ranging from 100 m to over 600 m. Existing empirical and semi-empirical displacement models tend to under estimate displacements at some sites and over estimate at others. The integrated datasets indicate that the areas with more severe and spatially extensive displacements are associated with thicker and more laterally continuous deposits of liquefiable soil. In some areas, the inland extent of displacements is constrained by geologic boundaries and geomorphic features, as expressed by distinct topographic breaks. In other areas the extent of displacement is influenced by the continuity of liquefiable strata or by the presence of layers that may act as vertical seepage barriers. These observations demonstrate the need to integrate geologic/geomorphic analyses with geotechnical analyses when assessing the potential for lateral spreading movements.