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The first site - Geonet has an image of all earthquakes of magnitude 3 or greater, split into three sequences separated by three main events. The first is Sept. 4th 2010 to 22nd February 2011, the second sequence through to 13th June 2011 and the final set until December 4th (the point at which the image was compiled).
This image very clearly shows that each of the three major earthquakes (on the dates separating the three time periods) marks an obvious change in the primary location of the earthquake swarms. Each swarm is located further east than the previous one. And in fact the earthquakes of the past 36 hours have generally been centred to the east of the city itself, marking a new centre of activity further east from the previous centre.
The other website of interest - Christchurch Quake Map allows the visitor to replay the sequence of all earthquakes between September 4th and the present day. Of interest is that this presentation uses a colour coding to indicate the depth of each event. We suggest users limit the display to magnitude 3 or greater events in order to get a clear, uncluttered view.
These two charts show a number of interesting trends.
