Legacy product - no abstract available

Legacy product - no abstract available

Legacy product - no abstract available

Legacy product - no abstract available

Geoscience Australia (GA) is currently undertaking a process of revising the Australian National Earthquake Hazard Map using modern methods and an updated catalogue of Australian earthquakes. This map is a key component of Australia's earthquake loading standard, AS1170.4. Here we present an overview of work being undertaken within the GA Earthquake Hazard Project towards delivery of the next generation earthquake hazard map. Knowledge of the recurrence and magnitude (including maximum magnitude) of historic and pre-historic earthquakes is fundamental to any Probabilistic Seismic Hazard Assessment (PSHA). Palaeoseismological investigation of neotectonic features observed in the Australian landscape has contributed to the development of a Neotectonic Domains model which describes the variation in large intraplate earthquake recurrence behaviour across the country. Analysis of fault data from each domain suggests that maximum magnitude earthquakes of MW 7.0-7.5±0.2 can occur anywhere across the continent. In addition to gathering information on the pre-historic record, more rigorous statistical analyses of the spatial distribution of the historic catalogue are also being undertaken. Earthquake magnitudes in Australian catalogues were determined using disparate magnitude formulae, with many local magnitudes determined using Richter attenuation coefficients prior to about 1990. Consequently, efforts are underway to standardise magnitudes for specific regions and temporal periods, and to convert all earthquakes in the catalogue to moment magnitude. Finally, we will review the general procedure for updating the national earthquake hazard map, including consideration of Australian-specific ground-motion prediction equations. We will also examine the sensitivity of hazard estimates to the assumptions of certain model components in the hazard assessment.

Legacy product - no abstract available

Legacy product - no abstract available

The aim of the NPE10 exercise is the continuation of the multi - technology approach started with NPE09. For NPE10, a simulated release of radionuclides was the trigger for the scenario in which an REB-listed seismo-acoustic event with ML between 3.0 and 4.8 was the source. Assumptions made were: A single seismo-acoustic signal-generating underground detonation event with continuous leak of noble gas, radionuclide detections only from simulated release. Using atmospheric transport modelling the IDC identified 48 candidate seismo-acoustic events from data fusion of the seismo-acoustic REBs with radionuclide detections. We were able to reduce the number of candidate seismo-acoustic point sources from 48 to 2 by firstly rejecting events that did not appear consistently in the data fusion bulletins; secondly, reducing the time-window under consideration through analysis of xenon isotope ratios; and thirdly, by clustering the remaining earthquakes and aftershocks and applying forward tracking to these (clustered) candidate events, using the Hy-split and ARGOS modelling tools. The two candidate events that were not screened by RN analysis were Wyoming REB events 6797924 (23-Oct) and 6797555 (24-Oct). Event 6797555 was identified as an earthquake on the basis of depth (identification of candidate depth phases at five teleseismic stations); regional Pn/Lg and mb:Ms - all indicating an earthquake source. Event 6797924, however, was not screened and from our analysis would constitute a candidate event for an On-Site Inspection under the Treaty.

Abstract is too large to be pasted here. See TRIM link: D2011-144613

The inventory of over 200 fault scarps captured in GA's Australian neotectonics database has been used to estimate the maximum magnitude earthquake (Mmax) across the Stable Continental Regions (SCRs) of Australia. This was done by first grouping the scarps according to the spatial divisions described in the recently published neotectonics domain model and calculating the 75th percentile scarp length for each domain. The mean Mmax was then found by averaging the maximum magnitudes predicted from a range of different published relations. Results range between Mw 7.0-7.5±0.2. This suggests that potentially catastrophic earthquakes are possible Australia-wide. These data can form the basis for future seismic hazard assessments, including those for building design codes, both in Australia and analogous SCRs worldwide.