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Images, UC QuakeStudies

A photograph of members of the Wellington Emergency Management Office Emergency Response Team in the hanger of a Royal New Zealand Air Force Hercules. The ERT members are travelling to Christchurch to help out in the emergency response to the 22 February 2011 earthquake. Blankets, tent poles, and other supplies have been stacked in the centre of the hanger.

Audio, Radio New Zealand

Christchurch Mayor Bob Parker, New standards for earthquake prone buildings in Christchurch, Some schools reopen, while others face permanent closure, PM says Defence Force's role to check CV, Plans to burn the Koran on hold not cancelled, Chances of magnitude aftershock hitting rapidly decreasing.

Research papers, University of Canterbury Library

Earthquakes cause significant damage to buildings due to strong vibration of the ground. Levitating houses using magnets and electromagnets would provide a complete isolation of ground motion for protecting buildings from seismic damage. Two types of initial configuration for the electromagnet system were proposed with the same air gap (10mm) between the electromagnet and reluctance plate. Both active and passive controller are modelled to investigate the feasibility of using a vibration control system for stabilizing the magnetic system within the designed air gap (10mm) in the vertical direction. A nonlinear model for the magnetic system is derived to implement numerical simulation of structural response under the earthquake record in Christchurch Botanic Gardens on 21 February 2011. The performance of the uncontrolled and the controlled systems are compared and the optimal combination of control gains are determined for the PID active controller. Simulation results show both active PID controller with constant and nonlinear attracting force are able to provide an effective displacement control within the required air gap (+/-5mm). The maximum control force demand for the PID controller in the presence of nonlinear attracting force is 4.1kN, while the attracting force in equilibrium position is 10kN provided by the electromagnet. These results show the feasibility of levitating a house using the current electromagnet and PID controller. Finally, initial results of passive control using two permanent magnets or dampers show the structural responses can be effectively reduced and centralized to +/-1mm using a nonlinear centring barrier function.

Images, eqnz.chch.2010

Laura Young and I tying down tarps over the hole in the roof. We did what we could to tie it down with tension and weigh it down with bricks tied to the tarps. Why? Because gale-force winds are predicted for tomorrow (Sunday) and rain on Tuesday.

Images, UC QuakeStudies

The Williams Street Bridge in Kaiapoi. This part of the footpath was damaged when the concrete abutment rose during the earthquake, forcing its way through the pavement and into the open. Fencing has been placed around this section of the bridge until work can be done to make it safe to walk on.