National Deformation Objective
Objective Leader: Dr. John Beavan
New Zealand is astride the boundary of the Pacific and Australian plates. In this objective we synthesise local measurements with global constraints to build up a national picture of the effects of plate boundary deformation. Vertical and horizontal deformation of the ground surface accumulates slowly across the width of the country every year, and occurs very rapidly during earthquakes. Geological structures record the accumulated deformation over much longer time intervals. We measure the present-day deformation and the results are used by Land Information New Zealand to define the national survey datum. The data is an important new input that may improve estimate of the national distribution of seismic hazard. The combined effects of vertical land movement and sea level rise will soon be determined sufficiently accurately in this objective for them to be useful in planning coastal development and sustainability. Finally, the stresses that are related to this deformation affect any type of deep drilling activity or fluid flow in the crust. This is particularly significant for petroleum exploration and exploitation.
We currently have five tasks within the objective:
1 GPS deformation map (leader, Dr. John Beavan): GPS measurements are compiled and combined to build an accurate picture of how surface deformation has occurred over the last decade.
2 Permanent deformation map (leader: Russ VanDissen): Active fault data are compiled and analysed to determine the long-term pattern of tectonic deformation. This includes vertical and horizntal motion of the land surface.
3 Remote sensing NZ deformation (leader Dr. Nicki Stevens): Remote data, such as satellite or airborne radar, are integrated with GPS data and used to better define the spatial pattern of deformation.
4 True sea level rise (leader Dr. John Beavan): Continuous GPS is used to measure land uplift or subsidence near tide gauges at key points around the country in order to correct the rate of sea level change measured by the tide gauges.
5 Stress state of the crust (leader Dr. David Darby): Petroleum industry data and geophysical observations and models are used to evaluate and predict the state of stress in the crust.
Selected publications
Beavan, J., Haines, J., 2001. Contemporary horizontal velocity and strain-rate fields of the Pacific-Australian plate boundary through New Zealand, J. Geophys. Res., 106:B1, 741-770.
Hannah, J. 2004: An updated analysis of long-term sea level change in New Zealand. Geophysical research letters 31.
Follow the links above to individual research project pages.