We report four lessons from experience gained in applying the multiple-mode spatially-averaged coherency method (MMSPAC) at 25 sites in Newcastle (NSW) for the purpose of establishing shear-wave velocity profiles as part of an earthquake hazard study. The MMSPAC technique is logistically viable for use in urban and suburban areas, both on grass sports fields and parks, and on footpaths and roads. A set of seven earthquake-type recording systems and team of three personnel is sufficient to survey three sites per day. The uncertainties of local noise sources from adjacent road traffic or from service pipes contribute to loss of low-frequency SPAC data in a way which is difficult to predict in survey design. Coherencies between individual pairs of sensors should be studied as a quality-control measure with a view to excluding noise-affected sensors prior to interpretation; useful data can still be obtained at a site where one sensor is excluded. The combined use of both SPAC data and HVSR data in inversion and interpretation is a requirement in order to make effective use of low frequency data (typically 0.5 to 2 Hz at these sites) and thus resolve shear-wave velocities in basement rock below 20 to 50 m of soft transported sediments.

The Bureau of Mineral Resources, Geology and Geophysics (BMR) conducted a seismic survey in the Denison Trough, in the western part of the Bowen Basin in Queensland in 1979. The survey continued work commenced in 1978 aimed at delineating the configuration of the trough and providing stratigraphic information from the Permian sequence which, in conjunction with current Geological Survey of Queensland stratigraphic studies, would enable reliable stratigraphic correlations to be made throughout the trough. The survey obtained 265 km of digitally recorded mainly six-fold Common-Depth-Point seismic reflection data.

Between October 2008 and February 2009, Geoscience Australia undertook two major surveys off the coast of Western Australia. Areas of interest included the Mentelle and northern Perth Basins, the Southern Carnarvon Basin, the sourthern Exmouth Sub-basin (Northern arnarvon Basin) and the Wallaby Plateau. These surveys collected a range of data, including 7300 kilometers of industry-standard seismic reflection data and 43000 line kilometers of gravity and magnetic data. In addition to the new data collected, Geoscience Australia has reprocessed 11700 line kilometres of open file 2D seismic data that exists within the survey area. This data is available for purchase as part of the Southwest Margin Data Package.

Prior to the development of Australian-specific magnitude formulae, the 1935 magnitude corrections by Charles Richter – originally developed for southern California – was almost exclusively used to calculate earthquake magnitudes throughout Australia prior to the 1990s. Due to the difference in ground-motion attenuation between southern California and much of Australia, many historical earthquake magnitudes are likely to be overestimated in the Australian earthquake catalogue. A method has been developed that corrects local magnitudes using the difference between the original (inappropriate) magnitude corrections and the Australian-specific corrections at a distance determined by the nearest recording station likely to have recorded the earthquake. These corrections have reduced the rates of local magnitudes of 4.5 in the historical catalogue by about 30% since 1900, while the number of magnitude 5.0 earthquakes has reduced by about 60% in the same time period. The reduction in the number of moderate-to-large-magnitude earthquakes over the instrumental period yields long-term earthquake rates that are more consistent with present-day rates, since the development of Australian-specific magnitude formulae. The adjustment of historical earthquake magnitudes is important for seismic hazard assessments, which assume a Poisson distribution of earthquakes in space and time.

No abstract available

The GEOPHYS_SURV database describes geophysical surveys (air, land, and marine), the datasets derived from those surveys, and the methods used for delivery of those datasets. The database includes metadata for all surveys conducted or managed by Geoscience Australia and its predecessor agencies, as well as data and surveys from State and Territory geological survey agencies.

This data set consists of processed seismic reflection data for line 01AGS-NY1 from the 2001 Northern Yilgarn seismic survey (L154), Western Australia. Line 01AGS-NY1 commenced in the Yilgarn Craton (Leonora) and extended to the east into the Officer Basin (east of Lake Yeo). The data were acquired by the Australian National Seismic Imaging Resource (ANSIR) using vibratory sources at a nominal 60 fold coverage. The seismic data are provided as SEG-Y files of stack and migrated data to 4 seconds and 18 seconds two-way time, at a sample interval of 4 milliseconds. CDP range is 1985 to 20860 with 20 metre CDP interval. SEG-Y header information, CDP coordinates as eastings and northings, and a pdf image of the migrated 18 second seismic section are also included. The line, migrated section images and further information on this data can be obtained from the <a href="http://www.pmdcrc.com.au" target="_blank">pmd*CRC</a> website.

TBA

This data set consists of processed seismic reflection data for line 01AGS-NY3 from the 2001 Northern Yilgarn seismic survey (L154), Western Australia. Line 01AGS-NY3 was located east of Lake Yeo within the Officer Basin and was acquired with vibratory sources at nominal 60 and 120 fold coverage by the Australian National Seismic Imaging Resource (ANSIR). The seismic data are provided as SEG-Y files of stack and migrated data to 4 seconds and 16 seconds two-way time, at a sample interval of 4 milliseconds. The CDP range is 2080 to 5507 with 15 metre CDP interval. SEG-Y header information, CDP coordinates as eastings and northings, and a pdf image of the migrated 16 second seismic section are also included. The line, migrated section images and further information on this data can be obtained from the <a href="http://www.pmdcrc.com.au" target="_blank">pmd*CRC</a> website.

This is a preliminary discussion