A snapshot of New Zealand's dynamic deformation field from Envisat InSAR
and GNSS observations between 2003 and 2011
Abstract
Measuring the deformation at the Earth’s surface over a range of spatial
and temporal scales is vital for understanding seismic hazard, detecting
volcanic unrest and assessing the effects of vertical land movements on
sea level rise. Here, we combine ~10 years of InSAR
observations from Envisat with interseismic campaign and continuous GNSS
velocities to build a high-resolution velocity field of New Zealand.
Exploiting the horizontal GNSS observations, we estimate the vertical
component of the deformation to provide the vertical land movement (VLM)
for the entire 15,000 km-long coastline. The estimated vertical rates
show large variability around the country as a result of volcanic,
tectonic and anthropogenic sources. Interseismic subsidence is observed
in Kaikoura region supporting models of at least partial locking of the
southern Hikurangi subduction interface. Despite data challenges in the
mountainous regions from landslides, sediment compaction and glaciers,
InSAR data shows localised uplift of the Southern Alps.