LATEST: GNS Science has upgraded the strength of yesterday’s earthquakes.
The largest earthquake has been upgraded to magnitude 6.3, with a shallower depth of 6km.
The 2.20pm quake was originally analysed as 6.0 in magnitude at a depth of 9km.
The 1.01pm tremor has also been upgraded to 5.7, and was at a depth of 10km - not 11km - new GNS figures show.
The quakes collapsed buildings, leaving homes without power and water, and caused widespread liquefaction.