GSWA South Yilgarn merged and levelled magnetic line data, AWAGS levelled

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 South Yilgarn merge, 1987-2005 survey were acquired in 1987 by the WA Government, and consisted of 392575 line-kilometres of data at a line spacing between 100m and 100m, and 60m terrain clearance. To constrain long wavelengths in the data, an independent data set, the Australia-wide Airborne Geophysical Survey (AWAGS) airborne magnetic data, was used to control the base levels of the survey data. This survey data is essentially levelled to AWAGS.

总磁强度（"Total Magnetic Intensity, TMI"）数据用于测量由地壳内造岩矿物成分差异引发的地球磁场强度变化。磁异常可分为正异常（磁场强度高于正常背景）与负异常（磁场强度低于正常背景），具体取决于岩石的磁化率。该数据集通过标准处理流程进行处理，以确保记录的磁场响应仅源于地下岩石。经处理后得到的数据集可通过解译揭示地下地质构造。GA地球物理学家会对处理后的数据开展质量核查，以确保GA发布的最终数据符合使用要求。这套源自1987-2005年南耶尔加恩（"South Yilgarn"）合并调查的测线数据集，于1987年由西澳大利亚州政府（"Western Australian Government, WA Government"）采集完成，总测线长度达392575测线公里，测线间距为100米至100米，飞行离地高度为60米。为压制数据中的长波长分量，我们采用独立数据集——全澳航空地球物理调查（"Australia-wide Airborne Geophysical Survey, AWAGS"）航空磁测数据——对本次调查数据的基准水平进行校正。本次调查数据实质上已平差至AWAGS基准。