An interesting video of a deliberate rockfall in the Sumner area near to Christchurch has been posted on this website.  Unfortunately I cannot embed it, but this screenshot provides a general idea of what it is like:

This was the result of a block being detached by work crews seeking to remove loose material generated by the earthquake sequence earlier this year.

Rockfalls during clearance works at the same site are also shown in this video:

The best section occurs between about 50 seconds and 1 minute 10 seconds.