Total magnetic intensity (TMI) data measures variations in the intensity of the Earth magnetic field caused by the contrasting content of rock-forming minerals in the Earth crust. Magnetic anomalies can be either positive (field stronger than normal) or negative (field weaker) depending on the susceptibility of the rock. The data 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 magnetic grid has a cell size of 0.002 degrees (approximately 210m). The data used to produce this grid was acquired in UNKNOWN by the WA Government, and consisted of UNKNOWN line-kilometres of data at 150.0m line spacing and 50.0m terrain clearance.

This dataset contains scanned geomagnetic magnetogram records from Wilkes Geomagnetic Observatory. Files names delineate the observatory, observation year, type of data, month range, folder and page. e.g. TOO 1985 GRAM - JUL - AUG - 73_00031 (TOO: Toolangi Observatory)(1985: Year)(GRAM: Magnetogram)(JUL - AUG: month range)(73_00031: Folder and page). Files are stored as station and year based PDF and individual tiff files per page.

Efforts are underway to digitally preserve seismograms, magnetograms and geomagnetic absolute observations from Australian observatories. These datasets are stored in original paper and film form and although they are available on request they are not easily discoverable or available at short notice to the public. The retrieval of analogue media is both time-consuming and labour-intensive and can cause further damage to deteriorating records. In this poster, we detail preserved examples of the handwritten records, microfilm, as well as original paper records dating back to 1959 for magnetograms from Wilkes Geomagnetic Observatory, and to 1902 for seismograms from Melbourne Observatory. Different generations of collected data have challenges associated with the preservation efforts, including; legibility, data compression algorithms, stability of the original medium and associated metadata. Additionally, costs and expertise required to create digital copies varies greatly between the different original mediums of data recordings. Our ongoing efforts have prioritised the preservation of the original analogue data through creation of digital copies before the record suffers from further deterioration, and, making those digital records publicly accessible through Geoscience Australia’s data servers to improve discoverability. Long term efforts following this will then be focused on digitisation for use with modern data analysis techniques. Presented at the 2022 Australian Earthquake Engineering Society (AEES) Conference.

Total Magnetic Intensity colour composite image 2015 The image was created from the Total Magnetic Intensity Grid 2015 - sixth edition. This image has a cell size of ~3 seconds of arc (approximately 80 m) and has been image enhanced for optimal display in Hue-Saturation-Intensity (HSI). This image only includes airborne-derived TMI data for onshore and near-offshore continental areas. Since the fifth edition was released in 2010 data from 41 new surveys have been added to the database, acquired mainly by the State and Territory Geological Surveys. It is estimated that 31 500 000 line-kilometres of survey data were acquired to produce the grid data, 4 500 000 line-kilometres more than for the previous edition.

This dataset contains scanned geomagnetic magnetogram records from Toolangi Geomagnetic Observatory. Files names delineate the observatory, observation year, type of data, month range, folder and page. e.g. TOO 1985 GRAM - JUL - AUG - 73_00031 (TOO: Toolangi Observatory)(1985: Year)(GRAM: Magnetogram)(JUL - AUG: month range)(73_00031: Folder and page). Files are stored as station and year based PDF and individual tiff files per page.

This dataset contains scanned geomagnetic magnetogram records from Mawson Geomagnetic Observatory. Files names delineate the observatory, observation year, type of data, month range, folder and page. e.g. TOO 1985 GRAM - JUL - AUG - 73_00031 (TOO: Toolangi Observatory)(1985: Year)(GRAM: Magnetogram)(JUL - AUG: month range)(73_00031: Folder and page). Files are stored as station and year based PDF and individual tiff files per page.

Total magnetic intensity (TMI) data measures variations in the intensity of the Earth magnetic field caused by the contrasting content of rock-forming minerals in the Earth crust. Magnetic anomalies can be either positive (field stronger than normal) or negative (field weaker) depending on the susceptibility of the rock. The data 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 magnetic grid has a cell size of 0.002 degrees (approximately 200m). The data used to produce this grid was acquired in UNKNOWN by the WA Government, and consisted of UNKNOWN line-kilometres of data at 300.0m line spacing and 60.0m terrain clearance.

Total magnetic intensity (TMI) data measures variations in the intensity of the Earth magnetic field caused by the contrasting content of rock-forming minerals in the Earth crust. Magnetic anomalies can be either positive (field stronger than normal) or negative (field weaker) depending on the susceptibility of the rock. The data 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 magnetic grid has a cell size of 0.002 degrees (approximately 210m). The data used to produce this grid was acquired in UNKNOWN by the UNKNOWN Government, and consisted of UNKNOWN line-kilometres of data at 200.0m line spacing and UNKNOWNm terrain clearance.

Total magnetic intensity (TMI) data measures variations in the intensity of the Earth magnetic field caused by the contrasting content of rock-forming minerals in the Earth crust. Magnetic anomalies can be either positive (field stronger than normal) or negative (field weaker) depending on the susceptibility of the rock. The data 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 magnetic grid has a cell size of 0.002 degrees (approximately 210m). The data used to produce this grid was acquired in UNKNOWN by the WA Government, and consisted of UNKNOWN line-kilometres of data at 1000.0m line spacing and UNKNOWNm terrain clearance.

<p>The Northern Territory Geological Survey (NTGS) designed the Mount Peake-Crawford survey to provide high resolution magnetic, radiometric and elevation data in the area. It is anticipated that the data from the survey would help attract explorers into ‘greenfield’ terranes and contribute to the discovery of the next generation of major mineral and energy deposits in the Northern Territory. A total of 120,000 line km of regional data (200m line spacing) and additional infill data (100m line spacing), flown at 60m flight height were acquired during the survey between July and October 2019. The survey was managed by Geoscience Australia. <p>Various grids were produced from the Mount Peake-Crawford Airborne Magnetic and Radiometric Survey dataset and simultaneously merged into a single grid file. The final grid retains all of the information from the input data and is levelled to the national map compilations produced by Geoscience Australia. The merged grids have a cell size of 20m. <p>The following merged grids are available in this download: <p>• Laser-derived digital elevation model grids (m). Height relative to the Australian Height Datum. <p>• Radar-derived digital elevation model grids (m). Height relative to the Australian Height Datum. <p>• Total magnetic intensity grid (nT). <p>• Total magnetic intensity grid with variable reduction to the pole applied (nT). <p>• Total magnetic intensity grid with variable reduction to the pole and first vertical derivative applied (nT/m). <p>• NASVD-filtered potassium concentration grid (%). <p>• NASVD-filtered thorium concentration grid (ppm). <p>• NASVD-filtered uranium concentration grid (ppm).