The earthquake occurred at 9:22 pm, [+1200 UTC] Wednesday, 15 July 2009 and the epicentre was located in Dusky Sound at the south-west corner of the South Island. Its magnitude of 7.8 makes its size comparable with the Buller (or Murchison) earthquake of 1929 and the damaging Hawke's Bay earthquake of 1931. It is also the largest earthquake of 2009 anywhere in the world (so far).
The deformation caused by the Dusky Sound earthquake resulted in the movement of the south-west of the South Island [ a foot] towards the west-south-west (in a direction somewhat to the south of Australia).
Large earthquake occurrence in New Zealand has shown clustering in time (mid-1800s and late 1920s to early 1940s). Therefore, in general, the probability of an event is higher after a large earthquake than before. ~ read more