Excerpt: (read here in full)
Scientists believe they have unearthed the trigger for the Canterbury earthquake.
Their potential breakthrough involves a second previously unknown fault under the Canterbury Plains.
Until now, the recently revealed Greendale Fault has been blamed for unleashing the magnitude-7.1 quake on September 4.
GNS Science seismologists working fulltime on the data recorded since then think the second fault may be responsible and provide the missing piece of the puzzle.