2022
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The radiometric, or gamma-ray spectrometric method, measures the natural variations in the gamma-rays detected near the Earth's surface as the result of the natural radioactive decay of potassium (K), uranium (U) and thorium (Th). 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. The terrestrial dose rate grid is derived as a linear combination of the filtered K, U and Th grids. A low pass filter is applied to this grid to generate the filtered terrestrial dose rate grid. This Cobar P5009 EXT 4 dose rate grid has a cell size of 0.00039074 degrees (approximately 40m) and shows the terrestrial dose rate of the Cobar Magnetic and Radiometric Survey, 2021. The data used to produce this grid was acquired in 2021 by the NSW Government, and consisted of 53617 line-kilometres of data at 200m line spacing and 60m terrain clearance.
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Digital Elevation data record the terrain height variations from the processed point- or line-located data recorded during a geophysical survey. This Cobar P5009 EXT 4 digital elevation model radar grid is elevation data for the Cobar Magnetic and Radiometric Survey, 2021. This survey was acquired under the project No. 5009 for the geological survey of NSW. The grid has a cell size of 0.00039074 degrees (approximately 40m). This grid contains the ground elevation relative to the geoid for the Cobar Magnetic and Radiometric Survey, 2021. It represents the vertical distance from a location on the Earth's surface to the geoid. The data are given in units of meters. The processed data is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose.
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The annual offshore petroleum exploration acreage release is part of the government’s strategy to promote offshore oil and gas exploration. Each year, the government invites companies to bid for the opportunity to invest in oil and gas exploration in Australian waters. The 2022 acreage release consists of 10 areas offshore of the Northern Territory, Western Australia, Victoria, and the Ashmore and Cartier Islands.
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Damaging earthquakes are less frequent in Australia when compared to other weather-related events, but when they do occur close to a community they can cause major damage and injury. This risk to property and life exists for building owners, particularly if the building is of vulnerable construction. The good news is that your building can be retrofitted to improve its earthquake resilience within a sensible budget without compromising its heritage value. This document seeks to show you how. It explains the nature of earthquake risk and provides resources for building owners on how the risk can be reduced for the most vulnerable building construction type: unreinforced masonry.
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Geoscience Australia is planning a deep crustal reflection seismic survey in South Australia, New South Wales and Victoria as part of the Exploring for the Future program
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The radiometric, or gamma-ray spectrometric method, measures the natural variations in the gamma-rays detected near the Earth's surface as the result of the natural radioactive decay of potassium (K), uranium (U) and thorium (Th). 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 Cobar magnetic and radiometric survey, NSW, 2021 (P5009), Extension 4, radiometric line data were acquired in 2021 by the NSW Government, and consisted of line-kilometres of data at 200m line spacing and 60m terrain clearance.
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At its nearest, northern Australia is just over 400 km from an active convergent plate margin. This complex and unique tectonic region combines active subduction and the collision of the Sunda-Banda Arc with the Precambrian North Australian Craton (NAC) near the Timor Trough and continues through to the New Guinea Highlands. Ground-motions generated from earthquakes on these structures have particular significance for northern Australian communities and infrastructure projects, with several large earthquakes in the Banda Arc region having caused ground-shaking-related damage in the northern Australian city of Darwin over the historical period. There are very few, if any, present-day tectonic analogs where cold cratonic crust abuts a convergent tectonic margin with subduction and continent-continent collision. Ground motions recorded from earthquakes in typical subduction environments are highly attenuated as they travel through young sediments associated with forearc accretionary prisms and volcanic back-arc regions. In contrast, seismic energy from earthquakes in the northern Australian plate margin region are efficiently channelled through the low-attenuation NAC, which acts as a waveguide for high-frequency earthquake shaking. As such, it is difficult to select models appropriate to the region for seismic hazard assessments. The development of a far-field ground-motion model to support future seismic hazard assessments for northern Australia is discussed. In general, the new model predicts larger ground motions in Australia from plate margin sources than models used for the 2018 National Seismic Hazard Assessment of Australia, none of which were considered fully appropriate for the tectonic environment. Short-period ground motions are strongly dependent on hypocentral depth and are significantly higher than predictions from commonly-used intraslab ground-motion models at comparable distances. The depth dependence in ground motion diminishes with increasing spectra periods. <b>Cite this article as</b> Allen, T. I. (2021). A Far-Field Ground-Motion Model for the North Australian Craton from Plate-Margin Earthquakes, <i>Bull. Seismol. Soc. Am. </i><b> 112</b>, 1041–1059, doi: 10.1785/0120210191
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Total magnetic intensity (TMI) data measures variations in the intensity of the Earth's 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 Cobar P5009 Main total magnetic intensity grid has a cell size of 0.00039074 degrees (approximately 40m). The units are in nanoTesla (or nT). The data used to produce this grid was acquired in 2021 by the NSW Government, and consisted of 53617 line-kilometres of data at 200m line spacing and 60m terrain clearance.
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Total magnetic intensity (TMI) data measures variations in the intensity of the Earth's 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. These line dataset from the Cobar Magnetic and Radiometric Survey, 2021 survey were acquired in 2021 by the NSW Government, and consisted of line-kilometres of data at 200m line spacing and 60m terrain clearance.
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Digital Elevation data record the terrain height variations from the processed point- or line-located data recorded during a geophysical survey. This Cobar P5009 EXT 1 digital elevation model radar grid is elevation data for the Cobar Magnetic and Radiometric Survey, 2021. This survey was acquired under the project No. 5009 for the geological survey of NSW. The grid has a cell size of 0.00039074 degrees (approximately 40m). This grid contains the ground elevation relative to the geoid for the Cobar Magnetic and Radiometric Survey, 2021. It represents the vertical distance from a location on the Earth's surface to the geoid. The data are given in units of meters. The processed data is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose.