In 2016 research in the Geodesy and Geodynamics Group has included studies of a diverse range of geophysical processes including changes to sea level, the Antarctic Ice Sheet, crustal deformation in Indonesia and modelling of the Earth’s gravity field.
Several advances in glacial isostatic adjustment (GIA) modelling occurred during 2016. A critical assessment of the ICE6G_C model by Peltier et al. (2015) was published by Purcell et al. (2016), which has exposed some of the flaws in the modelling approach adopted by the former group. In particular, the GIA modelling in the Antarctic seas using ICE6G_C over-estimates the present-day uplift rates, meaning that present-day mass loss rates may be larger than previously thought. Lambeck et al. (2016) completed a very detailed assessment of relative sea level indicators to derive a new ice sheet model for North America.
Crustal deformation studies focused on Indonesia in 2016, with results of GPS fieldwork identifying the locations of active faults in East Indonesia (Koulali et al., 2016a). Perhaps the most significant finding was the active slip found on a fault in East Java, quantified to be slipping at ~6 mm/yr. The results highlighted a previously unidentified seismic threat for East Java, drawing attention to the pronounced seismic and tsunami threat to Bali, Lombok, Nusa Tenggara, and other coasts along the Flores Sea. A subsequent study (Koulali et al., 2016b) showed that onshore faults in West Java are accommodating convergence of several mm/yr, again highlighting the importance of considering crustal fault activity on Java in future seismic hazard assessments.
Fault slip rate components from the model of Koulali et al. (GJI, 2016) computed along the Java Trench subduction zone, with rates shown in blue. The fault-parallel component is shown in dots in the inset.
In a new initiative, Dr McClusky was funded by ANU’s Myanmar Centre, through the “Government Partners for Development” program between DFAT, ANU and the University of Yangon, to investigate the feasibility of a joint study of the earthquake hazard in Myanmar. He visited the university in Myanmar twice this year and has established the framework in which a GPS observing program can be undertaken in the coming years.
Several staffing changes occurred during 2016. Dr Sebastien Allgeyer joined the GRACE project in October 2015 and has worked on improving the ocean tide modelling in the orbit analysis software. In October 2016, Dr Julia Pfeffer commenced working on an ARC Discovery project, led by Drs Purcell and Tregoning, to extract sea level changes around the Australian coastline from available satellite altimetry, tide gauge and glacial isostatic adjustment models. Ms Bianca Kallenberg submitted her PhD thesis in June 2016, while Mr Janosch Hoffmann resubmitted his PhD thesis in December 2016. Dr Michael Moore graduated this year after 4 years as a PhD student and has returned to his position at Geoscience Australia.