<p>Geoscience Australia has recently released its 2018 National Seismic Hazard Assessment (NSHA18). Results from the NSHA18 indicate significantly lower seismic hazard across almost all Australian localities at the 1/500 annual exceedance probability level relative to the factors adopted for the current Australian Standard AS1170.4–2007 (R2018). These new hazard estimates, coupled with larger kp factors, have challenged notions of seismic hazard in Australia in terms of the recurrence of damaging ground motions. As a consequence, the new hazard estimates have raised questions over the appropriateness of the prescribed probability level used in the AS1170.4 to determine appropriate seismic demands for the design of ordinary-use structures. Therefore, it is suggested that the ground-motion exceedance probability used in the current AS1170.4 be reviewed in light of the recent hazard assessment and the expected performance of modern buildings for rarer ground motions. <p>Whilst adjusting the AS1170.4 exceedance probability level would be a major departure from previous earthquake loading standards, it would bring it into line with other international building codes in similar tectonic environments. Additionally, it would offer opportunities to further modernise how seismic demands are considered in Australian building design. In particular, the authors highlight the following additional opportunities: 1) the use of uniform hazard spectra to replace and simplify the spectral shape factors, which do not deliver uniform hazard across all natural periods; 2) updated site amplification factors to ensure continuity with modern ground-motion models, and; 3) the potential to define design ground motions in terms of uniform collapse risk rather than uniform hazard. Estimation of seismic hazard at any location is an uncertain science. However, as our knowledge improves, our estimates of the hazard will converge on the actual – but unknowable – (time independent) hazard. It is therefore prudent to regularly update the estimates of the seismic demands in our building codes using the best available evidence-based methods and models.

The Geological Survey of Canada's 5th Generation seismic hazard model for Canada forms the basis for the seismic design provisions of the 2015 National Building Code of Canada (NBCC). We deaggregate the seismic hazard results for selected cities to help understand the relative contributions of the earthquake sources in terms of distance and magnitude. Deaggregation for a range of probabilities and spectral accelerations (Sa) from 0.2 to 10.0 seconds is performed to examine in detail the hazard for two of Canada's largest urban centres at highest risk, Vancouver in the west and Montréal in the east. A summary table of deaggregated seismic hazard is provided for other selected Canadian cities, for Sa(0.2), Sa(2.0) and peak ground acceleration (PGA) at a probability of exceedence of 2%/50 years. In most cases, as the probability decreases, the hazard sources closer to the site dominate. Larger, more distant earthquakes contribute more significantly to hazard for longer periods than shorter periods. The deaggregations allow better-informed choices of scenario events and for the selection of representative time histories for engineering design.

This dataset contains a collection of ESRI geodatabases that hold hazard and impact data derived as part of the Severe Wind Hazard Assessment for Western Australia (2017-2020) project. There are separate geodatabases for each community examined in the project. Within each community, multiple TC scenarios were analysed for each community. The list of scenarios is included below. Geodatabase structure --------------------- Within each geodatabase, the data is structured as set out below. The structure is repeated for each available scenario in that community. Note scenario id numbers have the hyphen ('-') removed in the <scenario id> string below. - Shapefiles |-- TCs within 50 km |-- Cat<X> <scenario id>_Impact [Polygon shape file of SA1-level mean damage state for residential housing] |-- Cat<X> <scenario id>_regionalwind [Polygon shape file of categorised regional wind speed] |-- Cat<X> <scenario id>_track_line [Line shape file of scenario track line segments] |-- Cat<X> <scenario id>_track_point [Point shape file of scenario track points] - Cat<X>_<scenario id>_localwind [Raster format local wind data] Scenarios --------- Scenairo Id number, TC intensity, Location 000-01322,3,Exmouth 013-00928,3,Exmouth 000-06481,5,Exmouth 003-03693,3,PortHedland 000-08534,5,PortHedland 012-06287,3,Broome 012-03435,5,Broome 006-00850,3,Karratha-Roebourne 009-07603,5,Karratha-Roebourne 011-01345,1,Carnarvon 003-05947,3,Carnarvon 011-02754,1,Geraldton 001-08611,3,Geraldton 007-05186,1,Perth bsh291978,1,Perth

Earthquake design standards seek to ensure that structures are adequately resilient to local hazard. The probabilistic hazard that forms the basis of the design loadings used and the methods by which they are calculated typically reflect the best available information and practices at the time. This was the case with the earthquake loadings standard for the design of PNG buildings that was published in 1982. However, with the collaborative development of a better understanding of earthquake hazard across PNG the need to adjust the earthquake loadings for design through an Interim Amendment was highlighted. This key step would precede any more general and broader update of national building regulations. In this paper the process taken to translate the latest earthquake hazard assessment for PNG, PSHA19, to design practice is described. This included an assessment of the level of current under-design and the engagement with stakeholders in PNG to assess their needs through workshop activity. The central document to this process, “The Interim Amendment to PNGS 1001-1982: Part 4: Earthquake Design Actions”, is described and goes beyond the incorporation of the new design hazard to the introduction of new approaches for assessing earthquake loads that more closely align with those used in New Zealand and Australia. Preparation and delivery of seminars in-country to familiarise design professionals with its use are also described along with the series of professional development video products also developed for use in PNG. Finally, future needs in regulatory development in PNG are outlined. Presented at the 2023 Australian Earthquake Engineering Society (AEES) National Conference

Geoscience Australia is currently drafting a new National Earthquake Hazard Map of Australia using modern methods and models. Among other applications, the map is a key component of Australia's earthquake loading code AS1170.4. In this paper we provide a brief history of national earthquake hazard maps in Australia, with a focus on the map used in AS1170.4, and provide an overview of the proposed changes for the new map. The revision takes advantage of the significant improvements in both the data sets and models used for earthquake hazard assessment in Australia since the original maps were produced. These include: - An additional 20+ years of earthquake observations - Improved methods of declustering earthquake catalogues and calculating earthquake recurrence - Ground motion prediction equations (i.e. attenuation equations) based on observed strong motions instead of intensity - Revised earthquake source zones - Improved maximum magnitude earthquake estimates based on palaeoseismology - The use of open source software for undertaking probabilistic seismic hazard assessment which promotes testability and repeatability The following papers in this session will address in more detail the changes to the earthquake catalogue, earthquake recurrence and ground motion prediction equations proposed for use in the draft map. The draft hazard maps themselves are presented in the final paper.

Manila is one of the world's megacities, and the Greater Metro Manila Area is prone to natural disasters. These events may have devestating consequences for individuals, communities, buildings, infrastructure and economic development. Understanding the risk is essential for implementing Disaster Risk Reduction programs. In partnership with AusAID, Geoscience Australia is providing technical leadership for risk analysis projects in the Asia-Pacific Region. In the Philippines, Geoscience Australia is engaging with Government of the Philippines agencies to deliver the "Enhancing Risk Analysis Capacities for Flood, Tropical Cyclone Severe Wind and Earthquake in the Greater Metro Manila Area" Project.

<div>Offshore probabilistic tsunami hazard assessments (PTHAs) are increasingly available for earthquake generated tsunamis. They provide standardized representations of tsunami scenarios, their uncertain occurrence-rates, and models of the deep ocean waveforms. To quantify onshore hazards it is natural to combine this information with a site-specific inundation model, but this is computationally challenging to do accurately, especially if accounting for uncertainties in the offshore PTHA. This study reviews an efficient Monte Carlo method recently proposed to solve this problem. The efficiency comes from preferential sampling of scenarios that are likely important near the site of interest, using a user-defined importance measure derived from the offshore PTHA. The theory of importance sampling enables this to be done without biasing the final results. Techniques are presented to help design and test Monte Carlo schemes for a site of interest (before inundation modelling) and to quantify errors in the final results (after inundation modelling). The methods are illustrated with examples from studies in Tongatapu and Western Australia.</div> Abstract submitted/presented to the International Conference on Coastal Engineering (ICCE) 2022 - Sydney (https://icce2022.com/). Citation: Davies, G. (2023). FROM OFFSHORE TO ONSHORE PROBABILISTIC TSUNAMI HAZARD ASSESSMENT WITH QUANTIFIED UNCERTAINTY: EFFICIENT MONTE CARLO TECHNIQUES. <i>Coastal Engineering Proceedings</i>, (37), papers.18. https://doi.org/10.9753/icce.v37.papers.18

The service contains the Australian Coastal Geomorphology Landform Subtype Classifications, used to support a national coastal risk assessment. It describes the location and extent of landform subtypes identifiable at scales between 1:25,000 and 1:10,000. It also provides further detail to the Landform Type, with particular reference to feature stability (e.g. dune types) and mobility (e.g. channel types).

Developing a framework and computational methodology for evaluating the impacts and risks of extreme fire events on regional and peri-urban populations (infrastructure and people) applicable to the Australian region. The research considers three case studies of recent extreme fires employing an ensemble approach (sensitivity analysis) which varies the meteorology, vegetation and ignition in an effort to estimate fire risk to the case-study fire area and adjacent region.

Tropical cyclone return period wind hazard layers developed using the Tropical Cyclone Risk Model. The hazard layers are derived from a catalogue of synthetic tropical cyclone events representing 10000 years of activity. Annual maxima are evaluated from the catalogue and used to fit a generalised extreme value distribution at each grid point.