Geotechnical characterization and seismic slope stability of rock slopes in the Port Hills during the New Zealand 2011 Canterbury Earthquakes

Field information from four rock-slope sites was used to study the seismic response and amplification effects induced in the Port Hills of Christchurch, New Zealand, by the 2011 Canterbury Earthquakes. The dynamic response of each slope was characterised in terms of input free-field seismic acceleration A_FF, slope yield acceleration K_Y, maximum crest acceleration A_MAX and the maximum average acceleration K_MAX. The measured permanent slope displacements at each site were used in back analysing numerical models of the stability of each slope. The amounts of permanent co-seismic slope displacement at the cliff sites were found to result from a combination of lithology, amplification, degradation and preconditioning prior to each event, and were unique for each site.