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Exploring Australian Hazard Map Exceedance Using an Atlas of Historical ShakeMaps

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Created 14/01/2025

Updated 14/01/2025

Seismic hazard models, commonly produced through probabilistic seismic hazard analysis, are used to establish earthquake loading requirements for the built environment. However, there is considerable uncertainty in developing seismic hazard models, which require assumptions on seismicity rates and ground-motion models (GMMs) based on the best evidence available to hazard analysts. This paper explores several area-based tests of long-term seismic hazard forecasts for the Australian continent. ShakeMaps are calculated for all earthquakes of MW 4.25 and greater within approximately 200 km of the Australian coastline using the observed seismicity in the past 50 years (1970-2019). A “composite ShakeMap” is generated that extracts the maximum peak ground acceleration “observed” in this 50-year period for any site within the continent. The fractional exceedance area of this composite map is compared with four generations of Australian seismic hazard maps for a 10% probability of exceedance in 50 years (~1/500 annual exceedance probability) developed since 1990. In general, all these seismic hazard models appear to be conservative relative to the observed ground motions that are estimated to have occurred in the last 50 years. To explore aspects of possible prejudice in this study, the variability in ground-motion exceedance was explored using the Next Generation Attenuation-East GMMs developed for the central and eastern United States. The sensitivity of these results is also tested with the interjection of a rare scenario earthquake with an expected regional recurrence of approximately 5,000 - 10,000 years. While these analyses do not provide a robust assessment of the performance of the candidate seismic hazard for any given location, they do provide—to the first order—a guide to the performance of the respective maps at a continental scale. This paper was presented at the Australian Earthquake Engineering Society 2021 Virtual Conference, Nov 25 – 26.

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Title Exploring Australian Hazard Map Exceedance Using an Atlas of Historical ShakeMaps
Language eng
Licence notspecified
Landing Page https://devweb.dga.links.com.au/data/dataset/02d20b3c-a38e-4f1e-882e-e71a9e50907f
Contact Point
Geoscience Australia
clientservices@ga.gov.au
Reference Period 08/04/2019
Geospatial Coverage {"type": "Polygon", "coordinates": [[[112.0, -44.0], [154.0, -44.0], [154.0, -9.0], [112.0, -9.0], [112.0, -44.0]]]}
Data Portal data.gov.au

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This dataset was originally found on data.gov.au "Exploring Australian Hazard Map Exceedance Using an Atlas of Historical ShakeMaps". Please visit the source to access the original metadata of the dataset:
https://devweb.dga.links.com.au/data/dataset/exploring-australian-hazard-map-exceedance-using-an-atlas-of-historical-shakemaps