To determine the magnitude of severe wind gust hazard due to thunderstorm downbursts using regional climate model output and analysis of observed data (including radar reflectivity and proximity soundings).

A multihazard (volcano, earthquake, tsunami) assessment for East New Britain Province, Papua New Guinea.

In 2009 Geoscience Australia (GA), Australia's national geoscience agency, initiated a project to update the National Earthquake Hazard Map for Australia. This talk will summarise the work done by the Earthquake Hazard Section to update the National Earthquake Hazard Maps and will also present the new maps themselves. The maps have mainly been designed to be used as a basis informing Australia's earthquake loading code. However they can also be used to help to improve Australia's ability to better prepare for earthquakes more generally. This talk will provide a brief overview of the work done for this project. Topics to be highlighted in this talk include how we put together a new catalogue of earthquakes for Australia and revised their magnitudes. Our new method for automatically classifying earthquakes as main shocks, foreshocks and aftershocks will also be discussed, as well the new set of earthquake source zones we have produced. In addition, the talk will also discuss new way we have tried to estimate the maximum expected magnitude for earthquakes in Australia from the results of GA's neotectonics program. The completely new set ground motion prediction equations for eastern Australia we have produced will also be presented. Finally, the talk will also show the revised and updated set of earthquake hazard maps based on the latest version of GA's EQRM (Earthquake Risk Model) code. The hazard and spectral curves for selected locations around Australia will be shown and the potential implications for earthquake risk will be briefly discussed. From the 9th International CO2 conference, Beijing 2013

Internal advice on tsunami, earthquake and severe wind hazards for the Kavieng Port region, derived from large-scale hazard assessments. This advice (refer TRIM D2021-55554) was provided to the Australia Pacific Climate Partnership (APCP) as part of Geoscience Australia's (GA's) contributions to the program. (In confidence report to APCP, not for distribution)

Internal advice on tsunami, earthquake and severe wind hazards for the Vanimo Port region, derived from large-scale hazard assessments. This advice (refer TRIM D2021-52746) was provided to the Australia Pacific Climate Partnership (APCP) as part of Geoscience Australia's (GA's) contributions to the program. (In confidence report to APCP, not for distribution)

ARR is a series of national guidelines and datasets fundamental to flood estimation. The work is being completed by Engineers Australia and funded by the Australian Government through the National Flood Risk Information Project at Geoscience Australia. This flyer is for promoting the revision of ARR at the Hydrology & Water Resources Symposium (HWRS 2015) in Hobart in December 2015.

In the last few years there have been several probabilistic seismic hazard assessments (PSHA) of Adelaide. The resulting 500 year PGA obtained are 0.059, 0.067, 0.109 and 0.141. The differences between the first three are readily accounted for by choice of GMPE, how faults are included and differences in recurrence estimation, with each of these having a similar level of importance. As no GMPEs exist for the Mt Lofty and Flingers Ranges the choices of GMPEs were all based on geological analogies. The choice of at what weighting to include low attenuation, that is a stable continental crust, GMPE was most important. At a return period of 500 year the inclusion of faults was not necessarily significant. The choice of whether the faults behaved with Characteristic or Gutenberg-Richter recurrence statistics had the highest impact on the hazard with the choice of slip rate the next most important. A low slip rate Characteristic fault, while increasing the hazard for longer return periods (i.e. ~2500 years), results in only a minor increase at 500 years. The magnitude frequency distribution b-value for the four studies were 1.043, 0.88, 0.915 and 0.724. For the same activity in the magnitude range of 3.0 to 3.5, the activity level at M 6.0 is an order of magnitude higher for a b-value of 0.724 compared to a b-value of 1.043. This increase in activity rate of larger earthquakes significantly increases the hazard. The average of the first three studies is 0.078±0.022 (0.056 -0.100) g. This range is reflecting the intrinsic uncertainty in calculating PSHAs where many of the inputs are poorly constrained. The results for the highest hazard level PSHA study (i.e. 0.141g) can be explained by their use of a low b-value (i.e. 0.724). M. Leonard1, R. Hoult2, P. Somerville3, G. Gibson2, D. Sandiford2, H. Goldsworthy2, E. Lumantarna2 and S Spiliopoulos1. 1Geoscience Australia, 2The University of Melbourne, 3 URS

As part of the 2018 National Seismic Hazard Assessment (NSHA), we compiled the geographic information system (GIS) dataset to enable end-users to view and interrogate the NSHA18 outputs on a spatially enabled platform. It is intended to ensure the NSHA18 outputs are openly available, discoverable and accessible to both internal and external users. This geospatial product is derived from the dataset generated through the development of the NSHA18 and contains uniform probability hazard maps for a 10% and 2% chance of exceedance in 50 years. These maps are calculated for peak ground acceleration (PGA) and a range of response spectral periods, Sa(T), for T = 0.1, 0.2, 0.3, 0.5, 1.0, 2.0 and 4.0 s. Additionally, hazard curves for each ground-motion intensity measure as well as uniform hazard spectra at the nominated exceedance probabilities are calculated for key localities.

Public concerns have been raised about the potential for induced seismicity as state and territory governments lift moratoriums on hydraulic stimulation activities for the exploration and extraction of unconventional hydrocarbons. The Scientific Inquiry into Hydraulic Fracturing in the Northern Territory articulated the need for a traffic-light system “to minimise the risk of occurrence of seismic events during hydraulic fracturing operations” within the Beetaloo Sub-basin. A temporary seismic network (Phase 1) was deployed in late 2019 to monitor baseline seismic activity in the basin. Based on the data analysed herein (November 2019 – April 2021), no seismic events were identified within the area of interest suggesting that the Beetaloo Sub-basin is largely aseismic. Observations to date indicate that there is potential to identify events smaller than ML=1.5 within the basin. The recent installation of ten semi-permanent stations for continuous real-time monitoring will contribute to ongoing baseline monitoring efforts and support the implementation of an induced seismicity traffic-light system. The outcome of this study will be used to build knowledge about potential human-induced seismic activity in the region that may be associated with unconventional hydrocarbon recovery. This paper was presented at the Australian Earthquake Engineering Society 2021 Virtual Conference, Nov 25 – 26.

You may not realise it but, on average, Australia is rattled every few days by an earthquake of magnitude 3 or above. We don’t feel every small tremor that happens, but the larger earthquakes are powerful enough to cause serious damage to buildings and infrastructure, putting our community’s safety at risk.