Earthquakes at shallow and intermediate depths in Fiordland, New Zealand

Accurate determination of earthquake hypocenters during a period of nearly two years has enabled the configuration of New Zealand's Fiordland seismic region to be examined in some detail. Crustal activity is largely confined to a strip 70 km wide, parallel to and including the coastline, whereas activity of intermediate depth defines a localized zone no more than 150 km long and 20–25 km thick, dipping steeply to the southeast and extending to a depth of 160 km. Positive gravity anomalies and Quaternary andesitic volcanism are also present, but these features are displaced from one another and from the intermediate-depth earthquakes by a distance comparable with the length of the seismic zone.