Developments for 3D gravity and magnetic modeling in spherical coordinates

Geoscience Australia (GA) is Australia's Commonwealth Government geoscientific agency. GA performs gravity and magnetic modeling at a range of scales, from broad regional crustal studies with thousands of kilometer lateral extent and tens of kilometer vertical extent, to detailed local studies with kilometer or less lateral extent and meters to hundreds of meters vertical extent. To achieve greater integration and coherence, and to better understand the geological significance of this work, GA are investing in a number of development projects; * Spherical coordinate gravity and magnetic modeling, * Modeling using High Performance Computing facilities, * Utilizing rock property data as an input into the modeling and interpretation of gravity and magnetic data, * Better management of geoscience data and models, and * Visualisation of spatial data in a Virtual Globe format. In collaboration with the Colorado School of Mines (CSM) and the China University of Geosciences (CUG), a capability to model gravity and magnetic data in a spherical coordinate framework is being developed. This will provide more accurate calculations and permit the results to be integrated into a single framework that more realistically reflects the shape of the Earth. Modeling gravity and magnetic data in a spherical coordinate framework is far more computationally intensive than in a Cartesian (rectangular) coordinate framework. To reduce the time required to perform the calculations in a spherical coordinate framework, the modeling software will be deployed by GA on the National Computational Infrastructure (NCI) High Performance Computing (HPC) facility at the Australian National University (ANU). This will also streamline the management of these software relative to the other main option of establishing and maintaining HPC facilities in-house. GA is a participant in the Deep Exploration Technologies Cooperative Research Centre (DET CRC). In combination with this involvement, there is support for improved management of rock property data and to develop methods to better understand how these data can be used to provide constraints for geophysical modeling. GA are also using the opportunities afforded through the DET CRC to improve documentation and standardization of data and model storage and transfer formats so that the tasks of management, discovery and delivery of modeling inputs and results to various users can be simplified and made more efficient. To provide the foundations of integration and analysis of information in a 3D spatial context, GA are utilizing and customizing 3D visualization software using a Virtual Globe application, NASA World Wind. This will permit us to view the spherical coordinate models and other information at global to local scales in a realistic coordinate framework. The various development activities will together play an important role in the on-going effort by GA to add value to large stores of potential field, rock property, and geological information. This will lead to a better understanding of the geology of the Australian region which will be used in a range of applications, including mineral and energy exploration, natural hazard mitigation, and groundwater management.