Isostatic Residual Gravity Anomaly Grid of Onshore Australia 2016

This grid is derived from gravity observations stored in the Australian National Gravity Database (ANGD) as at February 2016 as well as data from the 2013 New South Wales Riverina gravity survey. Out of the approximately 1.8 million gravity observations 1,371,998 gravity stations in the ANGD together with 19,558 stations from the Riverina survey were used to generate this image. The grid shows isostatic residual gravity anomalies over onshore continental Australia. The data used in this grid has been acquired by the Commonwealth, State and Territory Governments, the mining and exploration industry, universities and research organisations from the 1940's to the present day. The isostatic corrections were based on the assumption that topographic loads are compensated at depth by crustal roots following the Airy-Heiskanen isostatic principle. A crustal density of 2670 kg/m3 was used for the isostatic correction, with an assumed density contrast between the crust and mantle of 400 kg/m3. An initial average depth to Moho at sea level of 37 km was used in the calculation. The isostatic corrections were then applied to the Complete Bouguer Gravity Anomaly Grid of Onshore Australia 2016 to produce the Isostatic Residual Gravity Anomaly Grid of Onshore Australia 2016.本重力格网数据源自截至2016年2月收录于澳大利亚国家重力数据库（Australian National Gravity Database, ANGD）的重力观测资料，以及2013年新南威尔士州里弗赖纳（Riverina）重力调查采集的数据。本次构建共用到约180万条重力观测数据，最终选用其中ANGD内的1,371,998个重力测点，以及里弗赖纳调查的19,558个测点。本格网展示了澳大利亚陆域大陆的均衡剩余重力异常分布。本格网所用数据的采集时间跨度为1940年代至今，采集方包括澳大利亚联邦、各州及领地政府、矿业与勘探行业、高校及科研机构。本次计算采用的均衡校正基于艾里-海斯卡宁（Airy-Heiskanen）均衡原理，即假设地形负载通过地壳根带在深部获得补偿。均衡校正过程中，地壳密度设定为2670 kg/m³，地壳与地幔间的预设密度差为400 kg/m³；计算初始设定海平面处莫霍界面（Moho）的平均深度为37千米。随后将上述均衡校正应用于《2016年澳大利亚陆域完全布格重力异常格网》，最终生成《2016年澳大利亚陆域均衡剩余重力异常格网》。