Geoscience Australia in collaboration with the Geological Survey of Western Australia conducted a seismic testing program on the Eucla Basin carbonate sediments during May 2012, during a survey to collect deep seismic data across the western Eucla Basin. These data were collected as part of the Albany-Fraser Seismic Survey that consists of three traverses in south-east Western Australia with a total length of 671 km. The major aim of this survey was to image the basement relationship between the Yilgarn craton, the Albany-Fraser zone, and basement rocks further east. Much of this eastern area is covered by the limestones of the Eucla Basin, and there has been little seismic data acquired in this area. These tests were required to confirm the feasibility of collecting deep seismic data beneath the limestones through the region. Geoscience Australia has had little success in penetrating the limestones of the Eucla Basin in previous surveys. Several sets of recording parameters were tested, including 10 Hz geophones and lower frequency 4.5 Hz geophones as parallel spreads. Also, linear upsweeps were compared to low-dwell non-linear upsweeps designed to introduce more low frequency energy into the signal. Initial results from the testing program were encouraging. Production data were subsequently collected along the Trans Australia Railway access road as far as Haig, using Geoscience Australia's standard deep crustal seismic acquisition parameters.

In this study, using modelled seismic sources and assigned ground-motion equations, the level of seismic hazard in terms of Peak Ground Acceleration (PGA) was calculated for return period of 475 years. The calculations were performed for bedrock site conditions (Vs30=760 m/s). From the results it is evident that the seismic hazard reaches to its maximum level (i.e. PGA-1g for 475 yr return period) at the Huon Peninsula and southern New Britain regions. Disaggregation analysis revealed that moderate to large earthquakes occurring along the New Britain Trench mainly control the level of hazard at these locations. For the seismic hazard computations, the open-source computer program OpenQuake developed by Global Earthquake Model foundation (http://www.globalquakemodel.org/openquake) was used. It should be emphasized that the presented results are still preliminary and should not be interpreted as our final assessment of seismic hazard in PNG.

From ORGCHEM database

Seismic and navigation data for selected lines from seismic surveys T69A and T70A in SEGY format.

Near surface information can be obtained from regional seismic data showing the weathering and layering properties, as well as dipping bedrock structures. Hard limestone layers in the near surface overlying soft sediments make complex refracted arrivals and refraction statics are difficult to define and in some cases it is best not to apply refraction statics to the reflection data. For some of the data in this survey surface sand dunes over 10 m high caused significant time delays for reflected data and refraction statics were essential prior to further reflection processing. Numerous refraction models were produced and tested along the data. Refraction models provided useful information about layering in the near surface, and helped with the seismic processing. The refractor models also indicated the possible presence of ground water. In some places the refracted arrivals changed polarity indicating either change in thickness or hardness of the limestone at the near surface overlying slower unconsolidated sediments. These regions sometimes correlated with diminished reflections. Dip moveout (DMO) correction was essential to improve near surface steep dipping structures.

No abstract available

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.

<p>Geoscience Australia conducted a seismic survey in the central Eromanga Basin in Queensland from July to Late November 1982. This survey was a continuation of the work undertaken in 1980 and 1981 to investigate the structure, stratigraphy, geological and tectonic evolution, and petroleum potential of the area. The survey obtained 485 km of six-fold Common-Depth-Point reflection data, in the Adavale Basin, Cooladdi Trough and Pleasant Creek Arch areas.<p><b>Raw data for this survey are available on request from clientservices@ga.gov.au - Quote eCat# 74970</b>

<p>Geoscience Australia conducted a seismic survey in the Central Eromanga Basin in Queensland in 1980. This survey was part of a new multidisciplinary study to investigate the structure, stratigraphy, geological and tectonic evolution, and petroleum potential of the area. The survey obtained 478 km of six-fold Common-Depth-Point seismic reflection data, mostly along four long east-west traverses crossing sparsely investigated sedimentary basins between exploration wells. The basins crossed included the Warrabin Trough, Cooper Basin, and Eromanga Basin west of the Canaway Fault.<p><b>Raw data for this survey are available on request from clientservices@ga.gov.au - Quote eCat# 74972</b>

<p>Geoscience Australia conducted a seismic survey in the central Eromanga Basin in Queensland in 1981. This survey was a continuation of the work undertaken in 1980 to investigate the structure, stratigraphy, geological and tectonic evolution, and petroleum potential of the area. The survey obtained 438 km of six-fold Common-Depth-Point seismic reflection data, in the Quilpie Trough and over the Cooper and Thomson Synclines.<p><b>Raw data for this survey are available on request from clientservices@ga.gov.au - Quote eCat# 74971</b>