Regional horizontal deformation associated with the 1987 Edgecumbe earthquake, Bay of Plenty, New Zealand — An introduction

The regional horizontal deformation associated with the 1987 March 2 Edgecumbe earthquake is estimated by comparing measurements made to 15 survey stations before and after the event The stations are located up to 25 km from the epicentre in the Rangitaiki Plains. The main feature of the deformation is an extension of 0. 8 (0. 1) m between the northwestern and southeastern edges of the plains. However, there is a complex pattern of deformation on the plains, with apparent ground strains of up to 300 ppm extension in regions which have been faulted, and up to 70 (30) ppm contraction in the centre of the plains between the main fault traces.