The Earth Dynamics group is a newly formed amalgamation of the Geodynamics, Rock Physics and Structural Geology and Tectonics groups at RSES. Research in the Earth Dynamics group involves the integration of data and concepts from several fields to better understand Earth Dynamics on a wide range of temporal and spatial scales. We are interested in how earthquakes nucleate and propagate, how (and how fast) fluids and magmas move through deforming rock, why, when and where large ore deposits form, and how the planet surface responds to the waxing and waning of ice sheets. Through the integration of these many different disciplines we address the over-arching goal of understanding our planet so that we may benefit from the natural resources it produces, better guard ourselves against the natural hazards it poses and to understand how Earth is responding to our changing climate.
Highlights in 2017 include new results of crustal deformation in Java (Koulali et al., 2017a), earthquakes and slow-slip events on the Hikurangi subduction zone in New Zealand (Koulali et al., 2017b), separating different components of vertical land motion at tide gauges (Pfeffer et al., 2017) and a new ice sheet model for the North American continent (Lambeck et al., 2017). Several PhD student papers were published, covering topics of mass balance in Antarctica (Kallenberg et al., 2017), the theory and application of estimating biases in geocentre motion (Zannat and Tregoning, 2017a,b), modelling of tropospheric gradients using GPS data (Massoumi et al., 2017) and new outputs of hydrological models after the assimilation of total water storage and soil moisture information from the GRACE and SMOS satellite missions (Tian et al, 2017). New results of temporal gravity field estimates from GRACE data using our software were presented at the GRACE Science Team Meeting in Austin, Texas, in October.
Laboratory studies in rock deformation continued to focus on using high P, T experiments to develop understanding of wear processes and evolution of friction in the first milliseconds of earthquake slip. The new laser interferometry technique was used to record slip velocities on microsecond timescales during fast slip events was supported by microstructural analysis using electron microscopy. The results are applied to understanding (1) the dynamics of ore formation in active faults, and (2) factors controlling where highest fluid fluxes occur in faults. The 50th anniversary of the commissioning of Rig 1 in the Rock Deformation laboratory was celebrated at RSES in November with a 1-day colloquium during which many alumni of the rock deformation laboratory gave scientific presentations.
Bianca Kallenberg and Sareh Rajabi submitted their PhD theses, which were subsequently accepted. Salim Masoumi submitted his PhD thesis and currently making corrections necessary for completion.
Siru Zheng commenced her PhD in the Earth Dynamics group. Her work will focus on using a Kalman filter to analyse global and regional sea level change, assimilating tide gauge observations with satellite altimetry measurements of sea surface heights.
Emeritus, Honorary staff and Visitors
Anne Kockmeyer visited the group as an intern as part of her Masters degree at the University of Bonne, Germany. Anne worked on developing models for extracting steric sea level signals from tide gauge records. We also hosted two undergraduates, Ben Schiffer and Erin Gray, for 8 weeks as part of the Princeton International Internship Program. Erin worked on improving the modelling of GRACE satellite orbits using our in-house software while Ben worked on estimating geocentre motion on Earth from global GPS data.
Extended travel and outcomes
As part of her PhD research, Ms K Hayward had extended collaborative visits to labs at the University of Manchester, Ecole Normale Superieur (Paris) and INGV (Rome) to conduct experiments and learn techniques for measuring rapid elastic unloading of rock samples during fast shear failure events.
Outreach activities & Service roles external to ANU
Prof S F Cox provided a 2-day course on "Deformation processes and structural analysis on fracture-controlled hydrothermal ore systems" as part of the Society of Economic Geologists Annual Conference (SEG2017) at the China University of Geosciences, Beijing. He also presented a 1-day course at the University of Tasmania as part of the CODES Masters program. Cox also provided an evening lecture and demonstration of the deformation sandbox to a Canberra Rotary group.
Dr Paul Tregoning gave a presentation to Year 11 and 12 students at Narrabundah College on 21 February to highlight the need and usage of mathematics and computer programming in climate science studies.