Legacy product - no abstract available

Legacy product - no abstract available

Legacy product - no abstract available

Legacy product - no abstract available

Legacy product - no abstract available

Legacy product - no abstract available

Geoscience Australia has recently released the 2012 version of the National Earthquake Hazard Map of Australia. Among other applications, the map is a key component of Australia's earthquake loading code AS1170.4. In this presentation we will provide an overview of the new maps and how they were put together. The new maps take advantage of the significant improvements in both the data sets and models used for earthquake hazard assessment in Australia since the current map in AS1170.4 was 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 Hazard maps will be presented for a range of response spectral acceleration (RSA) periods between 0.0 and 1.0s and for multiple return periods between a few hundred to a few thousand years. These maps will be compared with the current earthquake hazard map in AS1170.4. For a return period of 500 years, the hazard values in the 0.0s RSA period map were generally lower than the hazard values in the current AS1170.4 map. By contrast the 0.2s RSA period hazard values were generally higher.

Compressional deformation is a common phase in the post-rift evolution of passive margins and rift systems. The central west Western Australian margin, between Geraldton and Karratha, provides an excellent example of strain partitioning between inverting passive margin crust and adjacent oceanic and continental crust. The distribution of contemporary seismicity in the region indicates a concentration of strain release within the basins diminishing eastward into the cratons. Very few data exist to quantify uplift or slip rates, however this pattern can be qualitatively demonstrated by tectonic landforms which indicate that the last century or so of seismicity is representative of patterns of Neogene and younger deformation. Pleistocene marine terraces on the western side of Cape Range indicate uplift rates of several tens of metres per million years, with similar deformation resulting in sub-aerial emergence of Miocene strata on Barrow Island and elsewhere. In the southern Carnarvon Basin, marine strandlines of unknown age are displaced by a few tens of metres, indicating uplift rates an order of magnitude lower than further west. Relief production rates in the western Yilgarn Craton are lower still - numerous scarps (e.g. Mt Narryer) appear to relate individually to <10 m of displacement across Neogene strata. The en echelon arrangement of such features distinguish them from those representing strain concentration in the craton proper, where scarps are isolated and typically <5 m high. Quantitative analysis of time-averaged deformation preserved in the aforementioned landforms, including study of scarp length as a proxy for earthquake magnitude, has the potential to provide useful constraint on seismic hazard assessments in a region which contains major population centres and nationally significant infrastructure.

Legacy product - no abstract available

Legacy product - no abstract available