IGMAS+: a success story of a 3-D potential field modelling software

Abstract

<p>In the context of research software sustainability, in this work we present the case of IGMAS+ (Interactive Gravity and Magnetic Application System) – a software tool for interactive 3-D numerical modelling, inversion, visualization and interpretation of potential fields together with some applications.</p><p>Modern workflows for geophysical interpretation and construction of 3-D data-constrained subsurface geophysical models in complex geological environments require software tools capable of handling multiple interdisciplinary and inhomogeneous input data, both seismic and non-seismic, like gravity and magnetics with their gradients, or magnetotelluric. These aspects imply big challenges not only in implementation and development of the modelling software, but also in organizing communication within the user community. A user of a research software often plays a role of a tester. Our joint goal as a research software community is to improve communication between developers and users, foster related technologies and overall culture of testing while using the research software.</p><p>Through the example of IGMAS+ we illustrate how a research software based on clear concepts with a well-established core algorithm can survive in the course of 40 years of development and still be useful, popular and demanded, at the same time being free for research and education purposes with a long-term plan to stay so. The software is largely used in creation of 3-D data-constrained subsurface structural density and susceptibility models at different spatial scales. Both large-scale models (thousands of square km) and regional (hundreds of square km), which we illustrate on several lithospheric-scale case studies, are important for understanding the drivers of geohazards. These models are necessary for efficient and sustainable extraction of resources, such as groundwater, deep geothermal energy or hydrocarbons, from sedimentary basins. Medium-scale models support studies on the usage of subsurface as thermal, electrical or material storage in the context of energy transformation. On the other hand, small-scale (tens of square km) models are largely used in applied geophysics, typically in sub-salt and sub-basalt settings. On the microscale (1 - 5 meters), the software presented here has also been used very successfully in the context of archaeological research and natural cavity localizations. Creation of all these models benefit a lot from the interactive modelling and inversion capabilities.</p><p>IGMAS+ is maintained and developed at the Helmholtz Centre Potsdam – GFZ German Research Centre by the effort of a research and development group limited by staff and time capacities. In these circumstances we find important to share our experience in organizing the development of the software and its documentation, the support of users, as well as our vision on the exchange of experience among the users.</p>

Crustal Structures From Receiver Functions and Gravity Modeling in Central Mongolia

“…The grid was calculated using the GEEC software (Saraswati et al., 2019; https://github.com/RodolpheCattin/GEEC). The 3D forward gravity modeling was performed using the IGMAS+ software (Anikiev et al., 2020; https://igmas.git-pages.gfz-potsdam.de/igmas-pages/). The other data can be obtained in the tables and the references.…”

“…The 3D forward gravity modeling was performed with the IGMAS+ software package (Anikiev et al., 2020; Gotze & Lahmeyer, 1988; Schmidt et al., 2011). The 3D block model is built by 32 north‐south oriented 2D parallel sections with spacing of 15 km, which contains the density units linked by polyhedrons with triangular surfaces connecting the vertices between the successive sections.…”

Inversion of potential fields by interactive optimization of 3D subsurface models using a spring-based space warping and evolution strategy

“…The workflow described therein allows the exact calculation of the gravimetric and magnetic potential, the three field components, and the six gradients in each case. This was initially programmed as IGAS (Interactive Gravimetric Application System) in the languages ALGOL and FORTRAN, and in the following decades was continuously developed further (using Java) into the actual already mentioned software package IGMAS+, which is cross-platform and is available for operating systems Windows, Linux, and MacOS (Schmidt et al, 2010;Alvers et al, 2014Alvers et al, , 2015aSchmidt et al, 2011Schmidt et al, , 2020Anikiev et al, 2020Anikiev et al, , 2021Götze et al, 2021). Because of the triangulated model structure, the software can handle complex structures (multi Z surfaces) like the overhangs of salt domes very well.…”

“…Examples include the work of Moorkamp et al (2016) and Wellmann and Caumon (2018) -among many others. A significant contribution to the integration of different independent information in the modeling process is the publicly available software IGMAS+ ("Interactive Gravity and Magnetic Application System", Anikiev et al (2020), see also Schmidt et al (2011) and IGMAS+ Team (2022)). It offers intensive work with geoinformation systems (InterOperable GIS) (Breunig et al, 2000).…”

“…An object-oriented program architecture, implemented using the Java programming language (Anikiev et al, 2020), is intended to enable further developments at a later stage and to ensure operational reliability. This concept should also facilitate the programming of interactive modeling procedures with real-time computation and real-time visualization.…”