Authors / CoAuthors
Geophysical Acquisition & Processing Section
Abstract
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. The processed data is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose. This South East Lachlan Gravity (CSCBA 1VD grid) is the first vertical derivative of the complete spherical cap Bouguer anomaly grid for the South East Lachlan Gravity Survey along Seismic Lines, P201930, Vic, NSW, 2019. This gravity survey was acquired under the project No. 201930 for the geological survey of NSW, VIC. The grid has a cell size of 0.0005 degrees (approximately 50m). A Fast Fourier Transform (FFT) process was applied to the original grid to calculate the first vertical derivative grid. A total of 3542 gravity stations at a spacing between 200m and 400m were acquired to produce this grid.
Product Type
dataset
eCat Id
144797
Contact for the resource
Point of contact
Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
ACT
2601
Australia
Keywords
- theme.ANZRC Fields of Research.rdf
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- EARTH SCIENCES
- ( Data centre )
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- NCI
- ( Discipline )
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- Earth sciences
- ( Discipline )
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- geophysics
- ( Feature type )
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- grid
- ( Place )
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- Australia
- ( Place )
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- NSW
- ( Place )
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- VIC
- ( Project )
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- survey 201930
- ( Theme )
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- GADDS2.0
- ( Theme )
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- gravity
- ( Theme )
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- spherical cap
- ( Theme )
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- Bouguer
- ( Theme )
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- complete
- ( Theme )
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- 1VD
- ( Theme )
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- first vertical derivative
- ( Theme )
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- ground digital data
- ( Theme )
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- geophysical survey
- ( Theme )
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- grav
- ( Theme )
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- grid
- ( Theme )
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- raster
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- Published_External
Publication Date
2020-10-31T00:00:00
Creation Date
2020-10-31T00:00:00
Security Constraints
Legal Constraints
Status
completed
Purpose
Maintenance Information
notPlanned
Topic Category
geoscientificInformation
Series Information
Lineage
This South East Lachlan Gravity (CSCBA 1VD grid) is the first vertical derivative of the complete spherical cap Bouguer anomaly grid for the South East Lachlan Gravity Survey along Seismic Lines, P201930, Vic, NSW, 2019. This gravity survey was acquired under the project No. 201930 for the geological survey of NSW, VIC. The grid has a cell size of 0.0005 degrees (approximately 50m). A total of 3542 gravity stations at a spacing between 200m and 400m 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 complete spherical cap Bouguer gravity anomalies were calculated by applying terrain correction (Bullard C) to the spherical cap Bouguer anomaly point data of South East Lachlan Gravity Survey along Seismic Lines, P201930, Vic, NSW, 2019. These terrain corrections were calculated using software from INTREPID Geophysics. The Intrepid algorithm utilises concentric rings subdivided into cells (Direen, 2001) to calculate the terrain correction. The terrain corrected data were then gridded using a gridding technique provided by 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 South East Lachlan Gravity Survey along Seismic Lines, P201930, Vic, NSW, 2019 survey 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. 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.
Parent Information
Geophysical Data Collection - gravity
UUID - c6b58f54-102c-19e9-e044-00144fdd4fa6,
eCat ID - 74512
Extents
[-37.2656, -36.0578, 145.7993, 150.0063]
Reference System
GDA94 (EPSG:4283)
Spatial Resolution
Service Information
Associations
Downloads and Links
Source Information
This South East Lachlan Gravity (CSCBA 1VD grid) includes ground gravity data for the South East Lachlan Gravity Survey along Seismic Lines, P201930, Vic, NSW, 2019 acquired for the geological survey of NSW, VIC