Hybrid modelling of gravity, gravity gradients and magnetic fields

Abstract

Modern geophysical interpretation requires an interdisciplinary approach and software capable of handling multiple geophysical data types such as seismic, full tensor gravity gradiometry, magnetics and magnetotellurics. We use the IGMAS+ (Interactive Gravity and Magnetic Application System) geo‐modelling software that is designed for 3D gravity, gravity gradient and magnetic modelling. This paper deals with a special aspect of potential field modelling, combining conventional triangulated model geometries (building polyhedrons) with voxel cubes. The hybrid modelling combines the advantages of both the vector and raster modelling system: both may be used alone (polyhedrons without voxels, voxels without polyhedrons) or simultaneously by superposition of both effects, which provides flexibility towards full interoperability. The key idea of our approach is, on the one hand to use two different, completely independent geometries (vector and raster) and give on the other hand the possibility to link both on demand for either editing the voxel model or to combine a large number of voxel cells under a common physical parameter function – which results in more reliable parameter inversion results.

Crustal structure across the Møre margin, mid-Norway, from wide-angle seismic and gravity data

“…The system uses polyhedrons with triangulated surfaces to approximate bodies of constant density and/or susceptibility, whose geometry is defined by a number of parallel vertical modelling sections. The system then calculates the potential field effect of the model at a designated station location (Götze and Lahmeyer, 1988;Schmidt et al, 2011).…”

Uncertainties in crustal thickness models for data sparse environments: A review for South America and Africa

“…Schmidt et al, 2011). This method works particularly well in areas of homogeneous seismic data cover where the constraints control the gravity inversion resulting in high accuracy for areas with point constraints.…”

A regional background model for the Arabian Peninsula from modeling satellite gravity gradients and their invariants

“…The 3D forward gravity model was made with the IGMAS + software package (Schmidt et al, 2011), that allows to model gravity and gravity gradients. The 3D representation of the subsurface is constructed by defining its geometry on a series of parallel 2D sections.…”