Research of the Geodynamics and Geodesy Group is concerned with the processes that deform the Earth's crust and lithosphere as well as the planet as a whole. The broad objective is to seek an improved understanding of the physical processes acting on and within the planet through both numerical modelling and observational analysis. The Earth is a dynamic planet, constantly deforming in response to forces acting on and within it on time scales that range from seconds to millions of years. The emphasis in the group is on developing new physical models and numerical algorithms that facilitate the testing of the models against geomorphological, geological and geodetic data so as to permit improved estimates of the force and response functions.
The problems being addressed by the Geodynamics Group can be viewed as being at different ends of the time scale. At the longer end of the scale, research is focused on the response of the Earth to the transfer of mass between the oceans and continental ice sheets during the major glacial cycles the Earth is currently experiencing. Evidence for detailed sea level histories is being obtained in a variety of ways for several parts of the Earth including the coasts of Australia, Antarctica and northwestern Europe. The combination of numerical modelling with this examination of the geological record makes it possible to infer the material properties of the Earth's mantle, including its effective viscosity on a timescale of tens of thousands of years, as well as placing constraints on the extent and distribution of the ice sheets themselves. Such quantitative information is crucial to the more speculative exercise of estimating the future sea-level variations which can be expected in response to climate change.
New developments in geodesy and geology have drawn our attention to very recent or "neotectonic" problems because it has become possible to directly measure rates of deformation and crustal loading. Thus some of the research activities of the group are being directed to neotectonic problems along the margins of the Australian Plate in Indonesia and Papua New Guinea. Remote sensing of changes on Earth through the use of space-geodetic missions such as GRACE (space gravity), satellite altimetry and GPS are all used to study processes related to sea level rise, hydrological loading, mass balance change of polar regions and precise satellite orbit determination. Software development to process observations from these satellite missions provides state-of-the-art analysis capabilities within our group.
Many of the research activities are carried out in cooperation with other areas of the School, most notably Seismology, Isotope Geochemistry, and Environmental Geochemistry. The research also involves cooperation with scientists from other Universities and Institutions both in Australia and overseas.