b'Education matters Theses in geophysics submitted to Australian universities in 2020PhD theses prevalent cratonic regions with criticallyI estimate a possible range of lower crust stressed lithosphere. The effectsviscosity in the San Andreas Fault system Hiwa Mohammadi, The Universityof varying source fault geometries(California), the Marlborough Fault Zone of Melbourne: Stress interactions inand kinematics on CFS fields and(New Zealand) and central Tibet (China). intraplate earthquakes subsequent seismicity are used to showSecond, using numerical modelling how progressive refinement of sourcemethods, I explore how lower crust fault models using emergent data canrheology contrast may affect the long-reduce epistemic uncertainties in theterm evolution of a major plate boundary role of CFS in earthquake triggering.fault. The case study is based on the San In some instances, increased sourceAndreas Fault, which is found to vary model complexity does not significantlydipping angles (~50-90) along strike. impact on CFS results and possibleThe moderately dipping strike-slip fault relationships to aftershocks relative tois not consistent with Anderson faulting simple source models. The thesis finallytheory. This inconsistency may be investigates the role lithospheric-scalereconciled if there are lateral variations flexural bending due to eustatic seain the lower crustal rheology across the level changes whether these impartfault plane that decrease fault dip with CFS perturbations on finite faults andtime. Third, in addition to strike-slip faults in regions of similar magnitude to thosein active tectonic settings, my study also Australia is a seismically active continentimparted by preceding earthquakes.includes reverse faults in stable cratonic with an intraplate compressive stressPreliminary age distributions of largeregions, especially for the cratonic areas field primarily driven by far-fieldpaleo-earthquakes on these reverseof western and southern Australia. I apply plate boundary interactions. Majorfaults are concurrent with CFS peaksstatistical methods to investigate the (magnitude5) surface-rupturingimparted by eustatic sea-level changes.co-seismic slip distribution of 11 surface-earthquakes are primarily sourced fromCFS of 0.1 to 1 bar on faults duringrupturing earthquakes in Australian reverse faults that perturb regional stressthe low-stand Marine Isotope (MIS)stable regions and provide a link fields and influence the spatiotemporalStage 2 to Stage 4 interval (ca. ~30 tobetween the shape and characteristics properties of subsequent earthquakes.~70 ka) provides tentative evidenceof co-seismic slip distributions and This thesis first contextualizes Australianthat earthquake clusters could bethe geophysical properties of the host earthquakes against global comparativesstimulated by sea-level lowstands.crust. Fourth, using a comprehensive by investigating 257 finite-fault ruptureThis thesis demonstrates the powergeophysical survey with the co-located models for 135 moment magnitudeand utility of CFS modelling to13GA-EG1 and 12GA-AF3 seismic (M w ) 4.1 to 8.1 continental earthquakesimprove understanding of intraplatereflection profiles and magnetotelluric worldwide. earthquakes. profiles and regional gravity and Haibin Yang, The University ofmagnetic maps in the Nullarbor Plain I find that: (i) Australian earthquakesMelbourne: The structure, rheology, and(Australia), I find that faults initiated are amongst the most kinematicallyrupture mechanics of seismogenic faultingback to the Proterozoic could still be and geometrically complex for theirin continental lithosphere reactivated in a Cenozoic convergent Mw, (ii) upper-bounds and variancesetting, especially for those major faults of the number of faults that rupturecutting to deep crust. Those deep-co-seismically increase with increasingpenetrating faults at terrane boundaries Mw, and (iii) multi-fault rupturecould be a potential channel for fluids to populations show no dependencypass through, and thus further weakened on strain rate or proximity to plateby the fluids, which is revealed by high-boundaries. The thesis then presents aconductivity anomaly in magnetotelluric suite of studies that model static andprofiles. The last research chapter of this visco-elastic coulomb stress changesthesis addresses a technical issue in the (CFS) imparted by major Australianparticle-in-cell finite element method, earthquakes on to receiver faultswhich is widely used in geodynamic and in the surrounding crust. I findnumerical modelling. As mixing materials that static CFS models provide anwith contrasting viscosity within one informative physical-statistical basis forelement results in stress fluctuations, characterising many post-mainshockI assess different smoothing methods seismic sequences in Australia, withThis thesis explores relationshipsto reduce the spurious stress in mixed-some exceptions. Aftershocks occurbetween the structure, rheology, andmaterial elements.predominantly within positive staticrupture properties of seismogenicMainak Mondal, Australian National stress lobes and close to the advancingfaulting in continental lithosphere fromUniversity: The role of convection on the viscoelastic positive stress lobes,four different perspectives. First, I derive abasal melting of Antarctic Ice shelvesespecially over the first few decadesscaling relationship that links the spacing after major earthquakes in thesebetween two nearly parallel strike-slipMelting of the Antarctic ice-shelves has regions. Earthquake triggering appearsfaults to the frictional strength, faulta large impact on ocean circulation, to occur under stress perturbations aswidth, and lower crust viscosity for strike- future sea level rise and the global small as ~ 0.001 to 0.01 bar, suggestingslip shear zones. Based on the scaling law,climate. Most of the ice-shelves in DECEMBER 2020 PREVIEW 30'