No abstract available

No abstract available

The Geophysical Processing and Data Access (GPDA) project at Geoscience Australia has undertaken a programme of collating, editing and cataloguing all bathymetry data in the Australian Region. For convenience this region has been loosely defined as extending from 5CS to 80CS and 45CE to 180CE. The contents of the Bathymetric Database consists of four datatypes: - Multibeam Echosounder Data (including LADS) - Singlebeam Echosounder Data - Depths from the digitisation of pre-existing maps - Depths: derived from remote sensing techniques (and produced grids) The dataset described by this metadata record is the Singlebeam Echosounder Dataset. It consists of the soundings from a number of marine surveys, that vary in size from a few hours data collection to surveys of several months duration. Data coverage of the defined region is very variable with some areas having quite dense data coverage whilst others are data poor. The datasets were collected by a variety of vessels (Australian and foreign) using a range of sensor systems. Although the formats often differed, nearly all datasets have been received as well defined ASCII files. Quite often the bathymetry data are associated with additional data such as shotpoint number, gravity, magnetics and sometimes an amplitude value of the returned echo. Further details can be found in the lineage section. In general the data are of good quality, although some poor segments of data are known to exist. Intersections with sources of reliable bathymetric data are needed to determine these poor data areas and to make data corrections and edits. More subtle problems such as wide angled beams, unknown (or poor) speed of sound corrections, poor navigation tidal and vessel draft corrections (in shallow water) are also known to exist. It is hoped that many of these problems can be minimised by tying these data to better quality datasets using modern bathymetric analysis applications. The original data files are maintained in UNIX directories. Those with sufficient metadata have also been loaded into the OZMAR database at Geoscience Australia

The GEBCO "One-Minute Grid" is based on the most recent version of the GEBCO Digital Atlas (GDA) bathymetric contours. Additional control contours and sounding data were used in many regions, particularly shallow water areas and semi-enclosed seas, to constrain the gridding process. It is a continuous digital terrain model for ocean and land, with land elevations derived from the Global Land One-km Base Elevation (GLOBE) database. As GA is only interested in the bathymetry in the Australian Region, the downloaded file was edited so that only the values in the Extents Box remained. The extract extends from 5°S to 80°S and from 45°E to 180°E. It must be stressed that although the GEBCO One Minute Grid is presented at one minute intervals of latitude and longitude, this does not imply that knowledge is available on sea floor depth at this resolution. It is important to note that, in most places, many miles exist between adjacent ship tracklines and that the grid is an interpolation based upon the input data. Further details of the data compilation and GEBCO grid construction are available from the 'User guide to the GEBCO One Minute Grid' ( http://www.bodc.ac.uk/data/online_delivery/gebco/documents/gridhelp.pdf).

Bathymetric map showing geological features with contours in metres. Includes Australian Fishing zone limit, seismic survey lines, petroleum exploration wells, for seabed south east of Eyre, W.A., Great Australian Bight, including Eyre Terrace and South Australian Abyssal Plain. Index to adjoining sheets, reliability diagram and locality map. Project coordination by C.R. Johnston, J. Williams, B. Willington ; data compilation D. Jongsma, H.L. Davies. "A joint project of the Hydrographic Service, RAN, Department of Defence, the Bureau of Resource Sciences and the Australian Geological Survey Organisation".

No abstract available

Complete set of 24 sheets This product is no longer available.

This dataset has been put together for the Australian Tsunami Warning System Project. Data for the dataset has been collected from a variety of international sources including the International Commission for the Geological Map of the World, Smithsonian Institution's Global Volcanism Program, GNS Science (New Zealand), Geological Survey of Indonesia, and the Geological Survey of Japan. A brief description of each dataset used is listed below, along with how the data was modified. Each dataset has been kept as individual ArcInfo coverages because of the differing scales and projections of the source data. Due to the variety of digital source data most items in the dataset do not comply with the current Geoscience Australia data dictionary or metadata standards.

The Geological and Oceanographic Model of Australia's Territory (GEOMAT- Harris et al., 2000) developed at Geoscience Australia provides maps indicative of the Australian seabed exposure. GEOMAT v.1 proposed a classification of the Australian under water territory based on sediment mobility induced by distinct processes such as tidal currents and gravity waves (Porter-Smith et al., 2004). GEOMAT v.2 proposed an improved classification of the continental shelf area based on a seabed exposure index (Hemer, 2006). The seabed exposure index was derived from the statistical distribution of the sediment transport rate, which reflected the strength and frequency of the combined wave-current bed shear stress. The bed shear stress was derived from a bottom boundary layer model (SEDTRANS - Li and Amos, 2001), which integrated the combined action of tidal currents (Egbert et al., 1994), oceanic currents (OCCAM : Webb et al., 1998), and gravity waves (AUSWAM - Greenslade, 2001) over a given mean sediment fraction (MARS : Geoscience Australia, 2006).

The Geophysical Processing and Data Access (GPDA) project at Geoscience Australia has undertaken a programme of collating, editing and cataloguing all bathymetry data in the Australian Region. For convenience this region has been loosely defined as extending from 5°S to 80°S and 45°E to 180°E. The contents of the Bathymetric Database consists of four datatypes: - Multibeam Echosounder Data (including LADS) - Singlebeam Echosounder Data - Depths from the digitisation of pre-existing maps - "Depths" derived from remote sensing techniques (and produced grids) The dataset described by this metadata record is the Multibeam Echosounder Dataset. It consists of the soundings of a number of multibeam surveys (170 by April 2007), that vary in size from a few km2 to about 250,000 km2 in size. Data coverage of the defined region is not complete. The datasets were collected by a variety of vessels (Australian and foreign) using a range of sensor systems. As a result the original data exist in a variety of raw data formats on a variety of media. These raw data have been archived in a secure repository at GA. For more details, one should access the metadata records for the individual surveys or the report given in the "Additional Metadata" section of this metadata record. All of the raw data have been imported into the CARIS HIPS application and processed using a common workflow. The processed data have then been exported as GSF "day" files (MBSystem format 121) and stored on Unix directories. These files are easily manipulated using most multibeam data applications