Magnetic Anomaly Map of Australia, Seventh Edition, 2020 - Enhanced Products Package - upward continued image (UC36km42kmRes)

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 2019 Total magnetic Intensity (TMI) grid of Australia has a grid cell size of ~3 seconds of arc (approximately 80 m). This grid only includes airborne-derived TMI data for onshore and near-offshore continental areas. Since the sixth edition was released in 2015, data from 234 new surveys have been added to the database, acquired mainly by the State and Territory Geological Surveys. The new grid was derived from a re-levelling of the national magnetic grid database. The survey grids were levelled to each other, and to the Australia Wide Airborne Geophysical Survey (AWAGS), which serves as a baseline to constrain long wavelengths in the final grid. It is estimated that 33 500 000 line-kilometres of survey data were acquired to produce the 2019 grid data, about 2 000 000 line-kilometres more than for the previous edition. 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 Anomaly Map of Australia, Seventh Edition, 2020 - Enhanced Products Package - upward continued image (UC36km42kmRes) is a pseudocolour image of the TMI grid of the Magnetic Anomaly Map of Australia, Seventh Edition, 2019.This grid has a cell size of 0.00083 degrees (approximately 88m). This pseudocolour image shows the magnetic response of subsurface features with contrasting magnetic susceptibilities. The image can also be used to locate structural features such as dykes.

总磁场强度（Total Magnetic Intensity, TMI）数据用于测量由地壳内造岩矿物成分差异所引发的地球磁场强度变化。磁异常可分为正异常（磁场强度高于正常水平）与负异常（磁场强度低于正常水平），具体取决于岩石的磁化率。2019年澳大利亚总磁场强度网格（TMI网格）的网格单元尺寸约为3角秒（约80米），该网格仅涵盖陆上及近岸陆地区域的航空测量总磁场强度数据。自2015年第六版发布以来，数据库已新增234项新勘测数据，这些数据主要由各州及领地地质调查局采集。新版网格基于国家磁场网格数据库的重新平差处理生成，各勘测网格之间已完成平差，同时以澳大利亚全域航空地球物理勘测（Australia Wide Airborne Geophysical Survey, AWAGS）作为基准，以约束最终网格中的长波长分量。据估算，为生成2019版网格数据，共采集了3350万测线公里的勘测数据，较上一版本多出约200万测线公里。数据通过标准流程进行处理，以确保记录的响应仅源于地下岩石。处理后得到的数据集可用于解译，以揭示地下地质结构。经处理的数据已由澳大利亚地质调查局（Geoscience Australia, GA）的地球物理学家进行质量检查，以确保GA发布的最终数据符合使用要求。《2020年第七版澳大利亚磁异常图》增强产品包中的向上延拓影像（UC36km42kmRes），是基于2019年第七版澳大利亚磁异常图TMI网格生成的伪彩色影像。该网格的单元尺寸为0.00083度（约88米），该伪彩色影像展示了具有不同磁化率的地下地质体的磁响应特征，还可用于识别岩墙等构造特征。