So, What's The Big Picture In Christchurch?

I let the processor go at this Web Site, which maps out earthquake epicenters. I chose "All" quakes since September 4, 2010 larger than magnitude 3.0 (which takes hours to plot).

As I've blogged about previously, the entire region of the North Canterbury Plains seems to be in a process of trying to rotate counterclockwise, to accomodate differential continental drift. The earthquakes seem to be occurring on faults that permit this movement.

In addition to the east-west faulting represented by the Greendale and Port Hills faults, there appear to be an underlying series of north-south faults in the region, visible here at Darfield, Lake Ellesmere, and Akaroa. Notice how the easternmost north-south line of epicenters lances right through the center of Akaroa? I bet Akaroa is on that fault! North-south faults have been mentioned by others as well.

I'm intrigued by the shallow earthquakes (labeled in orange and red), where brittle crust is simply shattered by tectonic stress, and seems to lead the progression of fault movement.

The progressive shift of earthquakes to the east may have stopped. It wouldn't be that surprising if fault movement just offshore starts propagating northwards, parallel to the coast on a north-south fault, and perhaps eventually crosses the coast again north of Christchurch.