The 2012 Australian Earthquake Hazard Map

This document presents a new set of earthquake hazard maps for consideration in the next revision of the earthquake loading code AS1170.4 "Structural design actions: Part 4 Earthquake actions in Australia". The earthquake catalogue used here includes events up until 2011. It is a combined version of several catalogues provided by external agencies. This represents the most complete catalogue of earthquakes compiled for Australia. The catalogue is more consistent through conversion of various magnitude measurements into a 'pseudo ML' scale. A systematic logic is used to select preferred magnitude types. Aftershocks, foreshocks and mine blasts have been identified and the declustered catalogue used here is cleaner than any previous Australian catalogue. Earthquake source zones applied in the hazard map use a unique combination of three different layers, which capture seismic characteristics at sub-national, regional and high-activity point scales. The map is one of the first in the world to apply a semi-quantitative measure of Mmax for majority of the source zones in the map. We apply recently developed ground motion prediction equations based on modern methods and data. These equations were used to calculate the ground motion at a range of response spectral accelerations, rather than just calculating the hazard for peak ground acceleration (PGA).

A suite of maps is calculated using GA's Earthquake Risk Model (EQRM). The EQRM is open-source, allowing the results to be tested or modified independently. The final 2012 Australian earthquake hazard maps for a range of return periods and response spectral periods are presented herein.

本文件提供一套全新的地震危险性地图（earthquake hazard maps），以供澳大利亚《AS1170.4 结构设计作用：第4部分 澳大利亚地震作用》下次修订时参考。本次所用的地震目录涵盖截至2011年的地震事件，系整合多家外部机构提供的多份目录而成，是迄今为止针对澳大利亚编制的最完整地震目录。通过将各类震级测量值统一转换为“伪ML”震级尺度，本目录的一致性显著提升；同时通过系统性逻辑优选震级类型。本研究已识别并剔除余震、前震及矿震事件，经去簇集处理后的目录相较于此前所有澳大利亚地震目录数据质量更优。本次危险性地图所采用的地震震源区，创新性结合了三层不同的数据图层，可分别捕捉国家级以下、区域尺度以及高活动点源尺度的地震活动特征。本图集是全球范围内首批针对多数震源区采用半定量最大震级（Mmax）赋值方法的地震危险性地图集之一。本次研究采用基于现代方法与数据开发的新型地面运动预测方程（ground motion prediction equations），这些方程被用于计算一系列反应谱加速度下的地面运动，而非仅针对峰值地面加速度（PGA）计算地震危险性。

整套地图集通过GA开发的地震风险模型（Earthquake Risk Model, EQRM）生成。该模型为开源项目，支持独立对结果进行验证或修改。本文最终呈现了2012年版澳大利亚地震危险性地图集，覆盖一系列重现期与反应谱周期工况。