The Quaternary Tectonic Framework of New Zealand and Relationship to Earthquake Hazard.

Abstract

New Zealand straddles the boundary between the Australian and Pacific crustal plates. There are three main elements to the Quaternay tectonic setting of New Zealand. They are; (i) The Kermadec-Hikurangi, west-dipping, subduction zone that extends along the east coast of New Zealand as far south as the Chatham Rise. (ii) In the southwest of the South Island, oceanic crust of the Australian plate is being subducted, at a steep angle, beneath continental crust of the Pacific plate at the Puysegur Trench. (iii) Between the two opposite-dipping subduction zones there is a transform fault system that accommodates relative plate motion between the plates. As a result of the complex tectonic setting there is a wide variety teceonic features, and variety in styles of deformation within New Zealand. The country can be divided into regions of similar tectonic style and rate, and this approach proves useful in identifying the principal components of the tectonic framework and in broadly assessing earthquake hazard.