Wiluna, WA, 1991 (P605), 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 Wiluna, WA, 1991 survey were acquired in 1990 by the WA Government, and consisted of 47000 line-kilometres of data at 400m line spacing 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）数据用于表征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水平）与负异常（磁场强度低于正常背景水平），具体取决于岩石的磁化率。本数据集采用标准流程进行处理，以确保记录的磁场响应仅源自地下岩石。经处理得到的数据集可通过地质解译揭示地下地质构造。经处理的数据已由GA地球物理学家开展质量核验，以确保GA发布的最终数据满足使用需求。这套1991年西澳大利亚州威尔纳（Wiluna）测线调查数据集，由西澳大利亚州政府于1990年采集完成，总测线长度达47000公里，测线间距为400米，地形离地高度为60米。为抑制数据中的长波长分量，研究人员引入独立数据集——全澳航空地球物理调查（Australia-wide Airborne Geophysical Survey, AWAGS）航空磁测数据——对本次测线数据的基准水平进行校正。本次调查数据已基本校准至AWAGS基准体系。