Major Faults in New Zealand
There are major fault lines running the length of New Zealand. Many of the larger faults are oblique strike slip faults, having a combination of sideways and vertical movement.
The North Island Fault System is a major plate boundary feature in the North Island, under constant stress from movement between the Pacific and Australian plates. Running in a continuous line from the Bay of Plenty southwards to the Wellington coast, this system has pushed up a line of mountain ranges including the Kawekas, Ruahines, Tararuas and Rimutakas.In the Wellington area several major faults are spread out parallel to each other, including the infamous Wellington Fault.
The Taupo Volcanic Zone also has many active faults associated with rifting and extension of the crust in the area.
In the South Island, the Marlborough Fault System is another series of major parallel faults.These join together further south to form the Alpine Fault which carries most of the total plate boundary strain. This is a very distinct feature along most of its length, and is clearly visible from space. It is considered to be at high risk of producing a major earthquake in the next 40 years. However, there are still many other relatively minor faults across the South Island, which rupture less frequently, such as those which have caused the Canterbury and Christchurch earthquakes.