TBA

Back projection using data from extended arrays, such as USarray, has become a powerful tool for examining the high frequency radiation from major earthquakes. Energy localisation is improved when data from more than one array is employed, and so far spatial resolution has been estimated by simulation. Fortunately, it is possible to build up the spatial resolution for back-projection from an arbitrary distribution of stations by using the configuration of the isochrons from each station passing through the target point in 3-D. It is therefore possible to test out the potential spatial resolution for a station configuration in areas of significance and thereby maximise potential resolution. As in hypocentre estimation the quality of the spatial operator is improved with good azimuthal control. As a consequence back-projection from a limited number of well-distributed stations or small arrays can be competitive with the use of much larger arrays with a limited azimuth span. This simplifies the task of near real-time processing to track the evolution of major events once a hypocentre has been estimated. We illustrate the potential for source recovery in 3-D for the very deep Mw 8.2 event in the Sea of Okhotsk. We also investigate appropriate station configuration for subduction zone mapping for the Indonesian region where there is considerable potential for megathrust events, but the epicentral distance is too large to allow direct use of North American stations.

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

No abstract available

No abstract available

Trace Energy Services was contracted by the Australian National Seismic Imaging Resource (ANSIR) to conduct the WA seismic 2004 survey in the eastern & northern Goldfields region of Western Australia. There were 148.59 km of 2D seismic reflection data recorded, 137.54 km over 29 traverses using Litton 315 Paystars and 11.05 km over 5 traverses using a single IVI Minivib as source. All lines were situated within the lease boundaries of gold mining companies, namely, Sons of Gwalia (Tarmoola & Gwalia) (L165), Placer Dome (Kanowna Belle, Wallaby, Granny Smith, Lancefield & Mt Morgans) (L166), Anglo Gold (Sunrise Dam) (L167) and Goldfields (St Ives at Kambalda) (L168),

<p>Geoscience Australia conducted a deep seismic reflection test survey in the onshore portion of the Otway Basin in the southeastern part of South Australia and southwestern part of Victoria, from late October to early November 1991. The seismic test survey was undertaken to test the feasibility of recording deep seismic reflection data prior to commencing a major deep seismic reflection survey in the Otway Basin. A planned major deep seismic reflection survey by AGSO formed part of a National Geoscience Mapping Accord (NGMA) project to study the early development of the Otway Basin. The seismic reflection test survey operated for a period of three weeks, including mobilisation and demobilisation to the survey area, with five test sites occupied during the test survey. The seismic test sites were positioned to examine the feasibility of recording deep seismic reflections in areas with different outcropping rock types along the proposed main seismic lines. eMF seismic profiles were recorded along all five test lines, with uphole shoots, shot depth and charge size comparison tests performed at several of the sites. Good quality deep seismic reflection events were recorded at several of the seismic test sites. The seismic test survey was important in highlighting areas with difficult shothole drilling conditions, especially the palaeo-sand dunes along the SA-Victoria border, and the Tertiary shelly sands with shallow water table near Lake Bonney. A major seismic survey would require all shothole drilling rigs to be equipped with portable mudpits to enable shotholes to be drilled in the palaeo-sand dunes and shelly sands.<p><b>Raw data for this survey are available on request from clientservices@ga.gov.au - Quote eCat# 74948</b>

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.

turned off record due to the lack of metadata, author/custodian and the product itself is un-locatable

turned off record due to the lack of metadata, author/custodian and the product itself is un-locatable