Here we present 3D and 2D resistivity models of the lithosphere beneath an area of southeast Australia, derived from Australian Lithospheric Architecture Magnetotelluric Project (AusLAMP) data and a subsequent infill broadband MT transect collected in October 2020. The Flinders Ranges, South Australia, is a zone that has been weakened by multiple Precambrian rift cycles related to the breakup of Rodinia, which may have led to the utilisation of this lithosphere for the focussing of fluid alteration causing high conductivities at crust and upper mantle depths in this region, as imaged in the AusLAMP 3D resistivity models. The northwestern end of a 100 km MT transect traverses this region and its 1.5 km MT site spacing resolves high conductivity pathways that broadly correlate with previously identified mineral prospects. These pathways straddle the resistive granodiorite rocks of the Anabama pluton, known to host porphyry-style mineralisation. To the southeast, the transect images the onlapping Mesozoic Murra Abstract presented at Australasian Exploration Geoscience Conference (AEGC), 15-17 September 2021, Brisbane, Australia

The Layered Geology of Australia web map service is a seamless national coverage of Australia’s surface and subsurface geology. Geology concealed under younger cover units are mapped by effectively removing the overlying stratigraphy (Liu et al., 2015). This dataset is a layered product and comprises five chronostratigraphic time slices: Cenozoic, Mesozoic, Paleozoic, Neoproterozoic, and Pre-Neoproterozoic. As an example, the Mesozoic time slice (or layer) shows Mesozoic age geology that would be present if all Cenozoic units were removed. The Pre-Neoproterozoic time slice shows what would be visible if all Neoproterozoic, Paleozoic, Mesozoic, and Cenozoic units were removed. The Cenozoic time slice layer for the national dataset was extracted from Raymond et al., 2012. Surface Geology of Australia, 1:1 000 000 scale, 2012 edition. Geoscience Australia, Canberra.

This web service delivers metadata for onshore active and passive seismic surveys conducted across the Australian continent by Geoscience Australia and its collaborative partners. For active seismic this metadata includes survey header data, line location and positional information, and the energy source type and parameters used to acquire the seismic line data. For passive seismic this metadata includes information about station name and location, start and end dates, operators and instruments. The metadata are maintained in Geoscience Australia's onshore active seismic and passive seismic database, which is being added to as new surveys are undertaken. Links to datasets, reports and other publications for the seismic surveys are provided in the metadata.

In the last decade, satellite derived standard land products have increasingly been produced for medium resolution satellites such as Landsat and (more recently) Sentinel-2. These mostly involve estimating surface reflectance and surface temperature. The products generally remove or standardise atmospheric effects with some also normalizing for surface bidirectional reflectance distribution function (BRDF) and terrain illumination effects to provide consistent time series and mosaics. The products have been used in various land surface applications, e.g., land cover, fractional cover and water identification, including flooding, crop monitoring and other time series analysis. However, the products are generally not immediately sufficient for applications over persistent water areas, such as estimating water quality, benthic cover, sediment transport, erosion and shallow water bathymetry. These need additional corrections with different physics that are not included in standard land products. In this paper, a method is proposed that treats persistent water areas separately within the standard product and includes corrections not generally applied to the land. The processing has been designed to be fully consistent between water and land in atmospheric correction and definition of reflectance factors so that they can be combined in the same time series and form mosaics. The first step in this process was acquisition of an effective and up to date classification to separate the persistent water and land. The water areas are then atmospherically corrected in the same way as the land but not treated for BRDF or shading effects as are the land areas. For the water areas, adjacency effects are more significant near water-land interfaces and water surface effects have different physics from land surfaces. The extra corrections currently include correction for adjacency effects as well as regional sun glint and sky radiation effects. The water mask and these corrections have been added to the current existing atmospheric, BRDF and terrain corrected surface reflectance product (standard product) from Geoscience Australia (GA). However, at the scale of the Landsat and higher resolution satellite images, residual local surface and bidirectional effects still occur and are discussed in this paper. In this paper, results from the new processing strategy have been compared with GA standard products in test images of Canberra and the North Queensland coast near Ingham and used as a basis to discuss the likely residuals of surface and atmospheric effects and options for the inclusion of methods to overcome them in a standard product. The results show that: • Both inland and sea water signatures behave as expected from other data and models. • Adjacency correction seems most useful where a water-Land interface is close to the water body. • Sky glint removal is sometimes too great in Canberra site when water is shielded by local terrain. • Sun and sky glint correction greatly improves the coast and deep sea water signatures. This Abstract was presented at the 22nd International Congress on Modelling and Simulation (MODSIM2017) Hobart Tasmania (https://www.mssanz.org.au/modsim2017/)

We present the first paleoseismic investigation of the Hyde Fault, one of a series of north-east striking reverse faults within the Otago range and basin province in southern New Zealand. Surface traces of the fault and associated geomorphology were mapped using a lidar digital elevation model and field investigations. Trenches were excavated at two sites across fault scarps on alluvial fan surfaces. The trenches revealed stratigraphic evidence for four surface-rupturing earthquakes. Optically stimulated luminescence dating constrains the timing of these events to around 47.2 ka (37.5–56.7 ka at 95% confidence), 34.6 ka (24.7–46.4 ka),23.5 ka (19.7–27.3 ka) and 10.5 ka (7.9–13.1 ka). We obtain a mean inter-event time of12.4 kyr (2.3–23.9 kyr at 95% confidence) and the slip rate is estimated to be 0.22 mm/yr (0.15–0.3 mm/yr). We do not find evidence to suggest that earthquake recurrence on the Hyde Fault is episodic, in contrast to other well-studied faults within Otago, suggesting diverse recurrence styles may co-exist in the same fault system. This poses challenges for characterising the seismic hazard potential of faults in the region, particularly when paleoearthquake records are limited to the most recent few events. <b>Citation:</b> Jonathan D. Griffin, Mark W. Stirling, David J.A. Barrell, Ella J. van den Berg, Erin K. Todd, Ross Nicolls & Ningsheng Wang (2022) Paleoseismology of the Hyde Fault, Otago, New Zealand, <i>New Zealand Journal of Geology and Geophysics</i>, 65:4, 613-637, DOI: 10.1080/00288306.2021.1995007

Abstract: Geomagnetic storms can cause power grid instabilities and blackouts due to excessive geomagnetically induced currents (GICs) flowing in electric transmission systems. In this study, we assess regional vulnerability to GICs by modeling the geoelectric fields induced by significant historic geomagnetic disturbance events in the presence of 3D subsurface geology using data from the Australian Lithospheric Architecture Magnetotelluric Project (AusLAMP) magnetotelluric array, Australia‐Wide Array of Geomagnetic Stations (AWAGS) magnetometer array, and Geoscience Australia geomagnetic observatory network. We analyze the vertical component of the magnetic field with respect to the horizontal magnetic‐field polarization for two magnetic storms and gain insight into the inductive effects associated with field polarization orientations in the 3D case. We also analyze the telluric field intensity and polarization for a unit geomagnetic field polarized in northerly and easterly directions at AusLAMP sites and find that in the presence of 3D geology the induced field has a very polarization‐sensitive anomaly. We model the geoelectric fields in southeastern Australia for the 1989 “Québec storm.” The induced ground electric fields are typically in the range 1,000–2,000 mV/km with a few sites within 2,000–5,000 mV/km on highly resistive regions and in coastal areas, and below 300 mV/km on inland sedimentary basins. The current study focuses on magnetic field variations with periods between 120 and ~20,000 s due to bandwidth limits in our magnetotelluric tensor data and the Nyquist limit for the 60 s sampling of our geomagnetic‐field data. Hence, our modeled maximum values should be considered lower estimates of potential real values. Plain Language Summary: We assess Australia's vulnerability to electric currents caused by geomagnetic storms. We use data from recent and historic geophysical studies to represent a range of possible geomagnetic‐field variations (including the extreme 1989 “Québec storm” event), and we use a three‐dimensional mathematical representation of the electrical conductivity of Australia's regional geology to represent the natural conductors in which electric currents can flow. Our analysis shows that the spatial variability of ground electric currents that can be caused by geomagnetic storms is closely associated with geologic structure. We find that ground electric currents are stronger in places where there are large differences between the conductivities of subsurface geologic structures. These include, for example, electrically resistive rocks near coastlines that are adjacent to deep and highly conductive oceans or, inland, where there are big contrasts between the electrical conductivities of different rock types. Away from such natural differences in electrical conductivity ground electric currents tend to be weaker. Every country on Earth has different types of rock that make up its geology, and many countries are bounded by an ocean. Vulnerability to electric currents caused by geomagnetic storms is an increasingly important issue, particularly in light of the mushrooming reliance of societies on high‐tech solutions to modern needs. The method we have developed for this research is readily extensible to other places to assess the risk posed by ground electric currents. <b>Citation:</b> Wang, L., Duan, J., Hitchman, A. P., Lewis, A. M., & Jones, W. V. (2020). Modeling geoelectric fields induced by geomagnetic disturbances in 3D subsurface geology, an example from Southeastern Australia. <i>Journal of Geophysical Research: Solid Earth</i>, 125, e2020JB019843. https://doi.org/10.1029/2020JB019843

Geoscience Australia’s geomagnetic observatory network covers one-eighth of the Earth. The first Australian geomagnetic observatory was established in 1840 in Hobart. This almost continuous 180-year period of magnetic-field monitoring provides an invaluable dataset for scientific research. Geomagnetic storms induce electric currents in the Earth, and feed into power lines through substation neutral earthing, causing instabilities and sometimes blackouts in electricity transmission systems. Power outages to business, financial and industrial centres cause major disruption and potentially billions of dollars of economic losses. The intensity of geomagnetically induced currents is closely associated with geological structure. Geomagnetic storm events across three decades have been analysed to develop a statistical model of geomagnetic storm activity in Australia and the model used to predict the intensity of geomagnetically induced currents in Australia's modern-day power grids. Modelling shows the induced electric fields in South Australia, Victoria and New South Wales caused by an intense magnetic storm that occurred in 1989. Real-time forecasting of geomagnetic hazards using Geoscience Australia’s geomagnetic observatory network and magnetotelluric data from the Australian Lithospheric Architecture Mapping Project helps develop national strategies and risk assessment procedures to mitigate space weather hazard. Abstract submitted to/ presented at 2021 Australasian Exploration Geoscience Conference -AEGC2021 (https://2021.aegc.com.au/).

Over the last decade there has been an exponential growth in MT data acquisition over the Australian Continent through collaboration between Geoscience Australia, state and territory governments and academics. This data is resulting in a step change in our understanding of the lithosphere and basin architecture. Abstract submitted/presented at 2017 Target Conference (https://www.aig.org.au/events/target-2017/)