Friday's quakes knocked out a further portion of the Western Wall of Christchurch Cathedral
[Photo Geoff Sloan]
Earthquake experts were surprised by the violence of the newest tremors beneath Christchurch, with reports showing ground acceleration far greater than expected for magnitude 5 and 6 quakes.
Four quakes of magnitude 5 or greater hit yesterday, the largest one a magnitude 6 which occurred 10km north of Lyttelton, and only 6km deep in Christchurch's hard basaltic rock.
The faultline of the largest quake was estimated to be 7km to 8km long, and its rupture caused the earth to slip about a metre.
Source and more: NZ Herald