At 4.35am households were woken up to a freight train noise that left thousands of homes rocking and rolling.
There were no fatalities -- but daylight revealed serious damage to Christchurch's commercial centre.
Buildings had collapsed and left cars flattened on the kerbside.
Closer to the Greendale fault line - near Darfield - roads and fence lines were shifted sideways by four metres.
The shallow quake lasted about 48 seconds as was felt as far as New Plymouth.