Wiluna Gravity Survey P201660 Spherical Cap Bouguer Anomaly 1VD  


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. This Wiluna Gravity Survey P201660 Spherical Cap Bouguer Anomaly 1VD is the first vertical derivative of the spheical cap Bouguer anomaly grid for the Wiluna Gravity Survey (P201660). This gravity survey was acquired under the project No. 201660 for the geological survey of WA. The grid has a cell size of 0.0076 degrees (approximately 800m). A total of 4453 gravity stations at variable spacing between 1000m and 2500m 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.

Product Type

dataset

eCat Id

143871

Contact for the resource

  Point of contact

Commonwealth of Australia (Geoscience Australia)  
Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
ACT
2601
Australia

Keywords

theme.ANZRC Fields of Research.rdf
  • EARTH SCIENCES
( Data centre )
  • NCI
( Discipline )
  • Earth sciences
( Discipline )
  • geophysics
( Feature type )
  • grid
( Place )
  • Australia
( Place )
  • WA
( Project )
  • survey 201660
( Theme )
  • GADDS2.0
( Theme )
  • gravity
( Theme )
  • spherical cap
( Theme )
  • Bouguer
( Theme )
  • 1VD
( Theme )
  • first vertical derivative
( Theme )
  • ground digital data
( Theme )
  • geophysical survey
( Theme )
  • grav
( Theme )
  • grid
( Theme )
  • raster
  • Published_External

Publication Date

2020-03-07T00:00:00

Creation Date

2020-03-07T00:00:00

Security Constraints

Australian Government Security ClassificationSystem    

Classification - unclassified

Legal Constraints

Creative Commons Attribution 4.0 International Licence    

Access - license

Use - license

Status

completed

Purpose

Maintenance Information

notPlanned

Topic Category

geoscientificInformation

Series Information

Lineage

This Wiluna Gravity Survey P201660 Spherical Cap Bouguer Anomaly 1VD is the first vertical derivative of the spherical cap Bouguer anomaly grid for the Wiluna Gravity Survey (P201660). This gravity survey was acquired under the project No. 201660 for the geological survey of WA. The grid has a cell size of 0.0076 degrees (approximately 800m). A total of 4453 gravity stations at a variable spacing between 1000m and 2500m 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 Wiluna Gravity Survey (P201660) 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.

Parent Information

Geophysical Data Collection - gravity

UUID - c6b58f54-102c-19e9-e044-00144fdd4fa6,

eCat ID - 74512

Extents

[-28.1176, -25.2312, 119.8946, 121.5885]

Reference System

GDA94 (EPSG:4283)

Spatial Resolution

Service Information

Associations

Association Type - operatedOnBy

Wiluna Gravity Survey P201660 Spherical Cap Bouguer Anomaly 1VD NCSS    

Association Type - operatedOnBy

Wiluna Gravity Survey P201660 Spherical Cap Bouguer Anomaly 1VD OPeNDAP    

Association Type - operatedOnBy

Wiluna Gravity Survey P201660 Spherical Cap Bouguer Anomaly 1VD WMS    

Association Type - operatedOnBy

Wiluna Gravity Survey P201660 Spherical Cap Bouguer Anomaly 1VD WCS    

Downloads and Links

File available for download in various formats from the GADDS2 portal  

Wiluna Gravity Survey P201660 Spherical Cap Bouguer Anomaly 1VD file download  

Wiluna Gravity Survey P201660 Spherical Cap Bouguer Anomaly 1VD NCSS  

Wiluna Gravity Survey P201660 Spherical Cap Bouguer Anomaly 1VD OPeNDAP  

Wiluna Gravity Survey P201660 Spherical Cap Bouguer Anomaly 1VD WMS  

Wiluna Gravity Survey P201660 Spherical Cap Bouguer Anomaly 1VD WCS  

Source Information

This Wiluna Gravity Survey P201660 Spherical Cap Bouguer Anomaly 1VD includes ground gravity point data for the Wiluna Gravity Survey (P201660) acquired for the geological survey of WA