Southland Otago Seismic Array

The Southland region of New Zealand lies at the peripheral edge of the Australian-Pacific plate boundary, and at the juxtaposition of multiple geologic terranes that were accreted onto the Gondwana margin during the Mesozoic. However, constraints on seismicity in this region, and the possible influence of its complex geologic history on modern day deformation processes, are limited by the sparse coverage of the permanent GeoNet network (station spacing ~100 km). To address this knowledge gap, we deployed 19x short period seismometers between October 2022-2023 as part of the Southland Otago Seismic Array (SOSA). Supplemented by GeoNet stations and a temporary deployment in neighbouring Fiordland (Fiord22), the reduced SOSA station spacing (10-30 km) has provided the first opportunity to study and characterise microseismicity in this region. This work is funded by Natural Hazard Commission Toka Tū Ake University Research Program project RCP023 `Understanding and Managing Seismic Risk in Low Seismic Zones.'