Full description
Gravity data measure small changes in gravity due to changes in the density of rocks beneath the Earth's surface. The data collected are processed via standard methods to ensure the response recorded is that due only to the rocks in the ground. The results produce datasets that can be interpreted to reveal the geological structure of the sub-surface.This p200880 Central Arunta Gravity spherical cap Bouguer Vert Deriv geodetic is the first vertical derivative of the spheical cap Bouguer anomaly grid for the Central Arunta Gravity Survey, NT (P200880). This gravity survey was acquired under the project No. 200880 for the geological survey of NT. The grid has a cell size of 0.0037 degrees (approximately 395m). A total of 11829 gravity stations at variable spacing between 500m and 4000m were acquired to produce this grid. A Fast Fourier Transform (FFT) process was applied to the original grid to calculate the first vertical derivative grid. The processed data is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose.
Lineage
Maintenance and Update Frequency: notPlanned
Statement: This p200880 Central Arunta Gravity spherical cap Bouguer Vert Deriv geodetic is the first vertical derivative of the spherical cap Bouguer anomaly grid for the Central Arunta Gravity Survey, NT (P200880). This gravity survey was acquired under the project No. 200880 for the geological survey of NT. The grid has a cell size of 0.0037 degrees (approximately 395m). A total of 11829 gravity stations at a variable spacing between 500m and 4000m were acquired to produce this grid. Three processes are required to correct the gravity observations for the effects of the surrounding topography: (1) a Bouguer correction (Bullard A), which approximates the topography as an infinite horizontal slab; (2) a correction to that horizontal slab for the curvature of the Earth (Bullard B); and (3) a terrain correction (Bullard C), which accounts for the undulations of the surrounding topography. The Spherical Cap Bouguer gravity anomalies were calculated by applying Bullard A and Bullard B corrections to the free air anomalies using a density of 2670 kg per cubic metre. These data were then gridded using the nearest neighbour algorithm from the INTREPID Geophysics software package. A first vertical derivative was calculated by applying a fast Fourier transform (FFT) process to the Bouguer gravity grid of the Central Arunta Gravity Survey, NT (P200880) to produce this grid. This grid was calculated using an algorithm from the INTREPID Geophysics software package. The processed data are checked by GA geophysicists using standard methods for assessing quality to ensure that the final data are fit-for-purpose. The final Spherical cap Bouguer anomalies grid contains data values which account for a correction due to the shape or curvature of the Earth, and provide a more accurate representation of crustal density variations beneath the Earth's surface. Details of the specifications of individual surveys held in the Australian National Gravity Database (ANGD) can be found in the Second Edition of the Index of Gravity Surveys (Wynne and Bacchin, 2009).
References:
Intrepid Geophysics, http://www.intrepid-geophysics.com;
Wynne, P., and Bacchin, M., 2009. Index of Gravity Surveys (Second Edition). Geoscience Australia, Record 2009/07.
Created: 09 03 2020
Issued: 09 03 2020
Modified: 05 07 2021
Data time period: 07 05 2008 to 07 08 2008
text: westlimit=131.3106; southlimit=-24.4036; eastlimit=138.015; northlimit=-20.8849; projection=GDA94 (EPSG:4283)
Subjects
1VD |
Australia |
Bouguer |
EARTH SCIENCES |
Earth sciences |
GADDS2.0 |
NCI |
NT |
Published_External |
first vertical derivative |
geophysical survey |
geophysics |
geoscientificInformation |
grav |
gravity |
grid |
ground digital data |
raster |
spherical cap |
survey 200880 |
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Other Information
The Geophysical Archive Data Delivery System (GADDS2) portal provides HTTP download of geophysics datasets in a number of formats. Point and line datasets are available in NetCDF and ASEG-GDF2. Grid datasets are available in NetCDF, GeoTIFF and ERS. (File available for download in various formats from the GADDS2 portal)
uri :
https://portal.ga.gov.au/persona/gadds
File download for p200880 Central Arunta Gravity spherical cap Bouguer Vert Deriv geodetic (p200880 Central Arunta Gravity spherical cap Bouguer Vert Deriv geodetic file download)
NetCDF Subsetting Service (NCSS) for p200880 Central Arunta Gravity spherical cap Bouguer Vert Deriv geodetic (p200880 Central Arunta Gravity spherical cap Bouguer Vert Deriv geodetic NCSS)
OPeNDAP web service for p200880 Central Arunta Gravity spherical cap Bouguer Vert Deriv geodetic (p200880 Central Arunta Gravity spherical cap Bouguer Vert Deriv geodetic OPeNDAP)
OGC Web Mapping Service (WMS) for p200880 Central Arunta Gravity spherical cap Bouguer Vert Deriv geodetic (p200880 Central Arunta Gravity spherical cap Bouguer Vert Deriv geodetic WMS)
OGC Web Coverage Service (WCS) for p200880 Central Arunta Gravity spherical cap Bouguer Vert Deriv geodetic (p200880 Central Arunta Gravity spherical cap Bouguer Vert Deriv geodetic WCS)
p200880 Central Arunta Gravity spherical cap Bouguer Vert Deriv geodetic NCSS
p200880 Central Arunta Gravity spherical cap Bouguer Vert Deriv geodetic OPeNDAP
p200880 Central Arunta Gravity spherical cap Bouguer Vert Deriv geodetic WMS
p200880 Central Arunta Gravity spherical cap Bouguer Vert Deriv geodetic WCS
Identifiers
- Local : pid.geoscience.gov.au/dataset/ga/143976
- global : df83bc4f-d936-451e-bd24-20d7c0087302
