SA Exploration Initiative 1994 - Area B9 (P709), 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 SA Exploration Initiative 1994 - Area B9 survey were acquired in 1994 by the SA Government, and consisted of 32637 line-kilometres of data at 400m line spacing and 85m 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）数据可量化地壳中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）两类，具体取决于岩石的磁化率。该数据通过标准化流程进行处理，以确保记录的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。经处理的数据需由GA地球物理学家开展质量核验，以确保GA发布的最终数据符合使用要求。本次提供的测线数据集源自1994年SA勘探计划B9区域调查项目，由SA政府于1994年采集，总数据覆盖长度达32637测线公里，测线间距为400米，飞行离地高度为85米。为约束数据中的长波长分量，研究人员采用独立数据集——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基于AWAGS数据完成了平差处理。