The New Zealand Sub-Crustal Rift

Abstract

The region (If deep-focus earthquake activity beneath New Zealand is described with the aid of epicentre maps and vertical cross sections. This region has been called the New Zealand Sub-Crustal Rift. Arguments based principally upon gravity observations suggest that the mean density of the material within the Rift is about 1 per cent less than that of adjacent parts of the mantle. The similarity of the pattern of New Zealand seismicity to that found in other parts of the world is briefly discussed.