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Summary Previous theoretical studies have shown that tank uplift, that is, separation of the tank base from the foundation, generally reduces the base shear and the base moment. However, there is a paucity of experimental investigations concerning the effect of uplift on the tank wall stresses, which is the principal parameter that controls the seismic design of liquid‐storage tanks. This paper reports a series of shake table experiments on a polyvinyl chloride model tank containing water. A comparison of the seismic behaviour of the tank with and without anchorage is described. Stochastically generated ground motions, based on a Japanese design spectrum, and three tank aspect ratios (liquid‐height/radius) are considered. Measurements were made of the stresses at the outer shell of the tank, the tank wall acceleration and the horizontal displacement at the top of the tank. While the top displacement and the tank shell acceleration increased when uplift was allowed, axial compressive stresses decreased by between 35% and 64% with tank uplift. The effect of uplift on the hoop stresses was variable depending on the aspect ratio. A comparison of experimental values with a numerical model is provided. Copyright © 2015 John Wiley & Sons, Ltd.

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The 2010 Canterbury earthquake sequence generated a large number of near-source earthquake recordings, with the vast majority of large events occurring within 30 km of Christchurch, New Zealand's second largest city. We utilize the dataset to estimate the site attenuation parameter, κ 0 , at seven rock and stiff-soil stations in New Zealand's GeoNet seismic network. As part of this study, an orientationindependent definition of κ is proposed to minimize the influence of observed highfrequency 2D site effects. Minimum magnitude limits for the traditional high-frequency fitting method are proposed, based on the effect of the source corner frequency. A dependence of κ 0 on ground-shaking level is also observed, in which events with large peak ground accelerations (PGAs) have lower κ 0 values than events with small PGAs. This observation is not fully understood, but if such a trend holds in future investigations, it may influence how κ 0 is used in hazard assessments for critical facilities. κ 0 values calculated from Fourier amplitude spectra of acceleration (κ 0;AS ) are compared with the native κ 0 of local, empirical, ground-motion prediction equations (GMPEs), calculated using the inverse random vibration theory method (κ 0;IRVT ). κ 0;IRVT is found to be independent of magnitude and distance and agrees with the average κ 0;AS for the region. κ 0;IRVT does not scale strongly with V S30 , indicating that current GMPEs may be capturing the average kappa effect through the V S30 scaling. The results from this study are of particular interest for site-specific ground-motion prediction studies as well as for GMPE adjustments between different regions or rock types.

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This report describes the observations and assessments of the team members on the effects of the earthquake on the ground, buildings and other structures, lifelines and the local community. Comment is made on the response to the earthquake and lessons are drawn for the New Zealand situation.

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