Geoscience Australia is the Australian Government advisor on the geology and geography of Australia, and develops the National Seismic Hazard Assessment (NSHA). The NSHA defines the level of earthquake ground shaking across Australia that has a likelihood of being exceeded in a given time period. Knowing how the ground-shaking hazard varies across Australia allows high hazard areas to be identified for the development of mitigation strategies so communities can be more resilient to earthquake events. The NSHA provides key information to the Australian Government Building Codes Board, so buildings and infrastructure design standards can be updated to ensure they can withstand earthquake events in Australia. Using the NSHA, decision makers can better consider: • What this could mean for communities in those areas and whether any further action is required • Where to prioritise further efforts • What this could mean for insurance and reinsurance premiums • Identify high and low hazard areas to plan for growth or investment in infrastructure

Earthquake hazard was not fully recognised in Australian building design until the mid-1990's. This oversight has resulted in a legacy of vulnerable buildings that can be readily damaged in moderate to severe Australian earthquakes. In particular, older unreinforced masonry buildings are particularly vulnerable and very common in the centres of our large cities and towns with significant heritage value. What can be done to cost-effectively address the risk they represent to people in the community and to protect these valued assets from future damaging earthquakes? With a focus on the Heritage town of York and the state capital of Melbourne, strategies have been examined as to effectiveness which have included a virtual retrofit to progressively reduce damage, injury, economic losses and emergency management logistics. Communication products derived from this work are described and initiatives to apply them in other Australian communities highlighted.

The National Seismic Hazard Assessment (NSHA) is a flagship Geoscience Australia product, used to support the decisions of the Australian Building Codes Board Standards Subcommittee BD-006-11, to ensure buildings and infrastructure are built to withstand seismic events in Australia. The NSHA has been updated in 2018 and includes significant advances on previous assessments including: inclusion of epistemic uncertainty using third-party source models contributed by the Australian seismology community, use of modern ground-motion models, and more. As a consequence of these advances, estimates of seismic hazard have decreased significantly across most Australian localities at the return period (of earthquake ground shaking) currently used by the Australian Standard. The objective of this document is to outline the significant changes to the NSHA18 from the 2012 version, and the science behind these changes. The responses were developed through feedback and consultation with experts in the seismic and engineering industry. If you have additional questions, please contact the project team at hazards@ga.gov.au.

When multiple earthquakes occur within a short period of time, damage may accumulate in a building, affecting its ability to withstand future ground shaking. This study aims to quantify the post-earthquake capacity of a nonductile 4-story concrete building in New Zealand through incremental dynamic analysis of a nonlinear multipledegree-of-freedom simulation model. Analysis results are used to compute fragility curves for the intact and damaged buildings, showing that extensive damage reduces the structure’s capacity to resist seismic collapse by almost 30% percent. The damage experienced by the building in mainshock, can be compared with the ATC-20 building tagging criteria for post-earthquake inspections, the purpose of which is to ensure public safety. Extensively damaged buildings, which are likely be red tagged, pose a significant safety hazard due to decreased strength in future earthquakes. The effect of mainshock damage is also compared for multiple and simplified single-degree-of-freedom models of the same building.

<b> This service will be decommissioned on 10/10/2024. The replacement service (with changes) is located at https://services.ga.gov.au/gis/rest/services/NEXIS_Residential_Dwelling_Density_v15/MapServer/</b> NEXIS (National Exposure Information System) Residential Dwelling Density web service is a set of four raster layers representing the density of residential dwellings across Australia at different scales and resolutions.

NEXIS (National Exposure Information System) Residential Dwelling Density is a set of four raster layers representing the density of residential dwellings across Australia at different scales and resolutions. Resolutions include 2km, 1km, 500m and 100m. The Australian Bureau of Statistics (ABS) defines dwelling units as self-contained suites of rooms including cooking and bathing facilities and intended for long-term residential use. Such dwelling units include houses-detached buildings used for long-term residential purposes-and other dwellings including flats. This product is based on NEXIS version 13 (2022) data.

Papua New Guinea (PNG) lies in a belt of intense tectonic activity that experiences high levels of seismicity. Although this seismicity poses significant risks to society, the Building Code of PNG and its underpinning seismic loading requirements have not been revised since 1982. This study aims to partially address this gap by updating the seismic zoning map on which the earthquake loading component of the building code is based. We performed a new probabilistic seismic hazard assessment for PNG using the OpenQuake software developed by the Global Earthquake Model Foundation (Pagani et al. 2014). Among other enhancements, for the first time together with background sources, individual fault sources are implemented to represent active major and microplate boundaries in the region to better constrain the earthquake-rate and seismic-source models. The seismic-source model also models intraslab, Wadati–Benioff zone seismicity in a more realistic way using a continuous slab volume to constrain the finite ruptures of such events. The results suggest a high level of hazard in the coastal areas of the Huon Peninsula and the New Britain – Bougainville region, and a relatively low level of hazard in the southwestern part of mainland PNG. In comparison with the seismic zonation map in the current design standard, it can be noted that the spatial distribution of seismic hazard used for building design does not match the bedrock hazard distribution of this study. In particular, the high seismic hazard of the Huon Peninsula in the revised assessment is not captured in the current building code of PNG. <b>Citation:</b> Ghasemi, H., Cummins, P., Weatherill, G. <i>et al.</i> Seismotectonic model and probabilistic seismic hazard assessment for Papua New Guinea. <i>Bull Earthquake Eng, </i><b>18</b>, 6571–6605 (2020). https://doi.org/10.1007/s10518-020-00966-1

This paper presents a methodology for post-earthquake probabilistic risk (of damage) assessment that we propose in order to develop a computational tool for automatic or semi-automatic assessment. The methodology utilizes the same so-called risk integral which can be used for pre-earthquake probabilistic assessment. The risk integral couples (i) ground motion hazard information for the location of a structure of interest with (ii) knowledge of the fragility of the structure with respect to potential ground motion intensities. In the proposed post-mainshock methodology, the ground motion hazard component of the risk integral is adapted to account for aftershocks which are deliberately excluded from typical pre-earthquake hazard assessments and which decrease in frequency with the time elapsed since the mainshock. Correspondingly, the structural fragility component is adapted to account for any damage caused by the mainshock, as well as any uncertainty in the extent of this damage. The result of the adapted risk integral is a fully-probabilistic quantification of post-mainshock seismic risk that can inform emergency response mobilization, inspection prioritization, and reoccupancy decisions.

Report is result of a rapid geological reconnaissance of the Federal Territory made primarily to locate deposits of limestone and shale, suitable for the manufacture of Portland cement, and other materials likely to be of value in the building of the Federal City.

This web service shows areas or locations occupied by an existing high-density urban development or known individual building structures in peri-urban and remote locations. Data used in this service is of varying levels of coverage and quality since it is aggregated from a variety of sources. The intended purpose of the service is to provide preliminary, first-pass information about urban environment, building structures and their distribution in landscape, as one of constraints on future development. Users should carry out further and more detailed investigations because this information is not meant to be a definitive source or support engineering phase planning. The service has layer scale dependencies.