The following Four Corners video stream explains granite...

The following Four Corners video stream explains granite fractures in some detail, they inverview Dr Adrian Williams from Geodynamics http://www.abc.net.au/4corners/content/2007/20070416_energy/video.htm

My understanding of granite fractures are that the cracks are already in the granite and they pass high pressure water through the cracks, if I am incorrect please someone correct me.

I agree that GRK's web site doesn't really explain well.