How do tectonic plates lock together?
2009 - 2012
Funder: Marsden Fund, Royal Society of New Zealand
Contact:Martin Reyners
New Zealand owes its high level of geological deformation to the fact that the boundary between the Pacific and Australian plates straddles the country. But this deformation only arises because, rather than sliding passively past each other, the plates lock together along various segments of the plate boundary. Understanding how and where the plate interface locks up is important for hazard assessments at plate boundaries worldwide, as locked regions accumulate elastic strain which will eventually be released in large earthquakes.
We are investigating the physical parameters controlling locking at the plate boundary beneath the North Island using two techniques:
1. detailed three-dimensional seismic tomography near the plate interface (the earthquake-wave equivalent of a medical CAT scan), and
2. analysis of how the distribution of small earthquakes near a locked part of the plate interface changes in response to slip on an adjacent part of the interface.
We know from GPS measurements that some parts of this plate boundary are strongly locked and others mostly slip freely. Thus by comparing and contrasting physical parameters along the plate boundary we will obtain fundamental insights into the factors that control plate locking.
Associate Investigators:
| Dr Donna Eberhart-Phillips | University of California Davis, USA |
| Dr Stephen Bannister | GNS Science |
| Professor Akira Hasegawa | Tohoku University, Japan |