Rate of Horizontal Fault Displacement in New Zealand

Abstract

ACCORDING to theories of plate tectonics1, a band of concentrated horizontal strain extends from a triple-point junction near 60° S 158° E through New Zealand to a triple-point junction near 2° S 128° E. The region of the band of strain within New Zealand is known as the Alpine Fault Zone2. From seafloor spreading rates and from the known horizontal strain directions on the Alpine Fault Zone, the rate of horizontal strain is estimated to be about 34 mm per year3,4. In the southern part of New Zealand, the fault zone is represented by the dextral Alpine Fault itself, and in the northern part by several sub-parallel dextral faults that branch off from the Alpine Fault (Fig. 1).