This paper discusses two of the key inputs used to produce the draft National Earthquake Hazard Map for Australia: 1) the earthquake catalogue and 2) the ground-motion prediction equations (GMPEs). The composite catalogue used draws upon information from three key catalogues for Australian and regional earthquakes; a catalogue of Australian earthquakes provided by Gary Gibson, Geoscience Australia's QUAKES, and the International Seismological Centre. A complex logic is then applied to select preferred location and magnitude of earthquakes depending on spatial and temporal criteria. Because disparate local magnitude equations were used through time, we performed first order magnitude corrections to standardise magnitude estimates to be consistent with the attenuation of contemporary local magnitude ML formulae. Whilst most earthquake magnitudes do not change significantly, our methodology can result in reductions of up to one local magnitude unit in certain cases. Subsequent ML-MW (moment magnitude) corrections were applied. The catalogue was declustered using a magnitude dependent spatio-temporal filter. Previously identified blasts were removed and a time-of-day filter was developed to further deblast the catalogue.

Earthquakes are a threat to life and property in Australia as demonstrated by the 1989 Newcastle earthquake (McCue & others, 1990). This report contains information on earthquakes of Richter magnitude 3 or greater reported in the Australian region during 1992. It is the thirteenth of an annual series compiled by the Australian Geological Survey Organisation (AGSO), using data from AGS0 and contributing seismological agencies in Australia. Its purposes are to aid the study of earthquake risk in Australia, and to provide information on Australian and world earthquakes for scientists, engineers and the general public. The report has six main sections: Australian region earthquakes; Isoseismal maps; Accelerograph data; Principle world earthquakes; and Monitoring of nuclear explosions.

The Indonesia Earthquake Hazard Program (IEHP) is a four-year project aimed at enhancing the capacity of the Government of Indonesia (GoI) to undertake earthquake hazard and risk assessments. The IEHP is a joint collaboration between the Australia-Indonesia Facility for Disaster Reduction (AIFDR), the GoI, Indonesian Universities and Geoscience Australia.

In order to calibrate earthquake loss models for the U.S. Geological Survey's Prompt Assessment of Global Earthquakes for Response (PAGER) system, two databases have been developed: an Atlas of ShakeMaps and a catalog of human population exposures to moderate to strong ground shaking (EXPO-CAT). The full ShakeMap Atlas currently contains over 5,600 earthquakes from January 1973 through December 2007, with almost 500 of these maps constrained by instrumental ground motions, macroseismic intensity data, community internet intensity observations, and published earthquake rupture models. The catalog of human exposures is derived using current PAGER methodologies. Exposure to discrete levels of shaking intensity is obtained by merging Atlas ShakeMaps with a global population database. Combining this population exposure dataset with historical earthquake loss data provides a useful resource for calibrating loss methodologies against a systematically-derived set of ShakeMap hazard outputs. Two applications of EXPO-CAT are illustrated: i) a simple objective ranking of country vulnerability to earthquakes, and; ii) the influence of time-of-day on earthquake mortality. In general, we observe that countries in similar geographic regions with similar construction practices tend to cluster spatially in terms of relative vulnerability. We find only limited quantitative evidence to suggest that time-of-day is a significant factor in earthquake mortality. Finally, we combine all the Atlas ShakeMaps to produce a global map of the peak ground acceleration (PGA) observed in the past 35 years, and compare this composite ShakeMap with existing global hazard models. In general, these analyses suggest that existing global and regional hazard maps tend to overestimate hazard.

This atlas of isoseismal maps of Australian earthquakes documents the ground intensity effects of 79 earthquakes. Most of these earthquakes originated in Queensland, northern New South Wales, and South Australia before 1982, and were not documented in the first atlas {BMR Bulletin 214) because their maps were not available at the time of publication; the remainder occurred in 1982 and 1983. The earliest map is for the November 1875 Mackay (Qld) earthquake and the most recent for the 1983 Beltana (SA) earthquake. This Bulletin and Bulletin 214 incorporate 163 maps from 149 earthquakes felt on the Australian continent, and provide a comprehensive database for earthquake risk assessments. Although the largest Australian earthquakes were included in Bulletin 214, this atlas contains maps of several early earthquakes of significance. These include the 1883 Gayndah (Qld), the 1886 Yass (NSW), and the 1913 Ravenswood (Qld) earthquakes, which had Richter magnitudes of 5.9, 5.5, and 5.7 respectively. The atlas is arranged in the same format as Bulletin 214: the isoseismal maps are presented in chronological order, each facing a page containing a brief description of the earthquake and the methods used to obtain the intensity data.

On the 16 April 2011 (05:31:18 UTC) Geoscience Australia (GA) recorded a ML 5.3 earthquake 50 km west of Bowen in central Queensland. This event was widely felt on the north Queensland coast and was followed by a number of aftershocks, which resulted in GA receiving more than 400 felt reports. Fifty earthquakes of magnitude <5.0 have been recorded in the region between Charters Towers and Mackay since 1900. However, during this same period only one M >5.0 earthquake is recorded; a ML 5.7 event located north of Ravenswood in December 1913. The April 2011 Bowen main shock was quickly followed by five smaller aftershocks ranging in magnitude from ML 3.2 to 4.1. Aftershocks were recorded by permanent seismic stations (e.g. Charters Towers, Eidsvold, Quilpie and Roma), however, the location, magnitude and depth of the smaller events is improved by four temporary stations which were established within four days of the main shock. The temporary sites were deployed between 10 and 48 km from the epicentre of the main shock to maximise the azimuthal coverage. Three-component seismometer and accelerometer data were recorded for a total of six weeks. With this dataset, existing information about several aftershocks was improved.

Nineteen ninety-three was a particularly quiet year for Australian earthquakes, only 59 events had a magnitude of ML 3.0 or more. No damaging earthqakes occurred in Australia and the largest at Tennant Creek in the Northern Territory, had a magnitude of ML4.8. The Tennant Creek earthquake sequence which began in 1986 continued its prolific although declining activity. Intensity questionnaires were distributed for small four earthquakes and isoseismal maps prepared for the events at the Gold Coast, Borumba Reservoir and Lady Elliot Island in Queensland and Willunga in South Australia. A swarm of small earthquakes occurred near Mukinbudin, 250 km east-north-east of Perth in Western Australia. The swarm was similar to others that have occurred in earlier years throughout the wheatbelt. Recordings of strong motion data were also sparce and none of them were of direct engineering significamce with only two earthquakes of magnitude ML > 2.9 triggering accelerographs. The highest acceleration recorded was 1260 mmls/s from a magnitude ML 2.7 earthquake at a distance of 0.5 km. Worldwide there were 13 major earthquakes, the largest with a magnitude of Ms 8.0 occurred south of the Mariana Islands on 08 August. No one was killed however 48 people were injured on Guam. The most devastating earthquake was an intraplate earthquake of magnitude Ms 6.3, which occurred in peninsula India near Latur and Killari on 29 September killing 9748 people. Several hundred people drowned when a large tsunami swept the Japan Sea following an earthquake in southwest Hokkaido and several other tsunamis were recorded. World-wide, more than 10 100 people died in earthquakes in 1993, compared with 2880 and 2800 in 1992 and 1991 respectively. The average for the century is about 10000 per year. During 1994, a single underground nuclear explosion was detonated; by China at the Lop Nor test site on 7 October. Other nuclear weapons States abided by a self-imposed moratorium on testing in recognition of the changed international political climate.

Geoscience Australia (GA) was engaged by Sydney Water Corporation (SW) to review existing geological, geophysical and geotechnical data from the Sydney region in an effort to better understand seismic hazard in SW's area of operations. The goal is to improve SW's understanding of the level of earthquake risk to their infrastructure in order to support their asset management practices. Of particular interest is improving SW's understanding of asset damage or loss and potential network disruption, following a large earthquake. The project outputs comprise two milestone reports. This document represents the first of these, and presents an earthquake hazard assessment of the SW area of operations based on the bedrock hazard definition outlined in the Australian Standard AS1170.4-2007. It also includes a seismic site classification of the soil conditions across the area based on mapped geology. The second milestone report, to be delivered by the end of June 2010, will incorporate a full probabilistic seismic hazard assessment of the SW area of operations, in addition to the hazard maps presented in the current report. The opening chapter of this first milestone report provides brief background information on earthquakes and the geology in the Sydney region. The second chapter covers the development and validation of the seismic site classification maps for the Sydney region. Two maps were produced; one created using the United States National Earthquake Hazard Reduction Program (NEHRP) classification scheme and one using the Australian Earthquake Loading Standard (AS1170.4-2007) classification scheme. Assessment of both the modified NEHRP and AS1170.4-2007 Australian Standard classifications have shown that both can be considered to satisfactorily represent the distribution of materials with varying potential to amplify earthquake ground shaking. This has been established by reclassifying existing mapped geology according to each classification, and testing the predicted classifications against independently acquired data from sub-surface investigations in the region. The final chapter presents maps showing the expected level of earthquake hazard in the SW area of operations using the site classification schema, hazard factors and tables given in AS1170.4-2007. A total of six hazard maps for SW's area of operations are presented for three spectral periods (0 s, 0.2 s and 1.0 s) and return periods of 500 years and 800 years. The results show that ground shaking at 0.2 s spectral period generally represents the highest hazard at 500 year and 800 year return periods. For areas with similar AS1170.4-2007 bedrock hazard values the environments characterised by Cenozoic sedimentary units have the highest earthquake hazard. While every effort has been made to ensure that the maps provided are as reliable as possible, GA cannot guarantee the accuracy or completeness of the information presented as the products are subject to the limitations of the available input data and changes in best practice methods. Therefore, this information should not be solely relied upon when making commercial decisions. In particular, local site conditions can be highly variable at the scale of individual structures, and only a site specific assessment can truly characterise the site conditions and thus the hazard at any given site.

We describe a weighted-average approach for incorporating various types of data (observed peak ground motions and intensities, and estimates from ground motion prediction equations) into the ShakeMap ground motion and intensity mapping framework. This approach represents a fundamental revision of ShakeMap technique, particularly as it pertains to processing ground motion and intensity data. Combining ground motion and intensity data onto composite ShakeMaps proves invaluable for loss calibration of historical events as well as for loss estimation in near-real time applications. In addition, the increased availability of near-real-time macroseismic intensity data, the development of new relationships between intensity and peak ground motions, and new relationships to directly predict intensity from earthquake source information, have facilitated the inclusion of intensity measurements directly into the ShakeMap computations. Our approach allows for the possible combination of all of the following data sources and estimates: 1) nearby observations (ground motion measurements and reported intensities), 2) converted observations from intensity to ground motion (or vice-versa), and 3) estimated peak ground motions from prediction equations (or numerical estimates).

Legacy product - no abstract available