Holger Kessler

The capture and dissemination of integrated 3D geospatial knowledge at the British Geological Survey using GSI3D software and methodology

The Geological Surveying and Investigation in 3 Dimensions (GSI3D) software tool and methodology has been developed over the last 15 years. Since 2001 this has been in cooperation with the British Geological Survey (BGS). To-date over a hundred BGS geologists have learned to use the software that is now routinely deployed in building systematic and commercial 3D geological models. The success of the GSI3D methodology and software is based on its intuitive design and the fact that it utilises exactly the same data and methods, albeit in digital forms, that geologists have been using for two centuries in order to make geological maps and cross-sections. The geologist constructs models based on a career of observation of geological phenomena, thereby incorporating tacit knowledge into the model. This knowledge capture is a key element to the GSI3D approach. In BGS GSI3D is part of a much wider set of systems and work processes that together make up the cyberinfrastructure of a modern geological survey. The GSI3D software is not yet designed to cope with bedrock structures in which individual stratigraphic surfaces are repeated or inverted, but the software is currently being extended by BGS to encompass these more complex geological scenarios. A further challenge for BGS is to enable its 3D geological models to become part of the semantic Web using GML application schema like GeoSciML. The biggest benefits of widely available systematic geological models will be an enhanced public understanding of the sub-surface in 3D, and the teaching of geoscience students.

The application of 3D geological modelling to aquifer recharge assessments in an urban environment

The development of an attributed 3D model of the Quaternary deposits across 75 km2 of central Manchester and Salford is providing a basis for new types of applied (thematic) outputs. Proprietary software designed specifically for use in Quaternary sequences has been used to construct a model of the glacial and post-glacial sequences in an area now undergoing rapid regeneration. The potential of the model to deliver information relevant to a range of practical applications is illustrated by an urban groundwater case study centred on the industrial area of Trafford Park. The sensitivity of the Permo-Triassic sandstone bedrock aquifer to pollution and the extent to which recharge may occur have been analysed through detailed characterization of the underlying superficial deposits. Potential hydrogeological pathways from ground surface to the sandstone are identified, and thematic outputs show the importance of the Manchester Ship Canal and related waterways as potential sources of recharge and pollution of the bedrock aquifer. The move towards 3D modelling of the shallow subsurface provides flexibility in meeting user needs that is not available from conventional 2D geological sources. It is suggested that modelling of this type should be used by site developers and remediators to design more targeted and cost-effective site investigations and risk assessments.

Reconstructing flood basalt lava flows in three dimensions using terrestrial laser scanning

We present a new method for reconstructing flood basalt lava flows from outcrop data, using terrestrial laser scanning (TLS) to generate three-dimensional (3D) models. Case studies are presented from the Faroe Islands and the Isle of Skye (UK), both part of the North Atlantic Igneous Province (NAIP). These were analyzed to pick out lava flow tops and bases, as well as dykes, lava tubes, and sedimentary layers. Three-dimensional surfaces were then generated using modeling software, and 3D geological models constructed. Finally, the models were interrogated to give data on flow thickness and crust-to-core ratio. The aim of this research is to obtain quantitative data on the internal heterogeneity of a sequence of flood basalt lava flows, and to provide high-resolution information about flow geometries and volcanic facies variations in 3D. Lava flow sequences display complex stacking patterns, and these are difficult to understand from photos or outcrop observations. Laser scanning allows us to study inaccessible outcrops, while avoiding the perspective distortion in conventional photography. The data from this study will form parts of larger models of flood basalt provinces, which will be used to improve seismic imaging in areas of basalt cover, and aid our understanding of facies architecture in flood basalts.

The use of 3D geological models in the development of the conceptual groundwater model

The conceptual groundwater model is heavily dependent on the geological framework which is used to defi ne the aquifer being studied. In the past, two-dimensional datasets such as geological maps and cross-sections were used in coordination with site-specifi c point data to build a conceptual understanding at the site or catchment scale. This is then simplified and it is this simplifi ed version which is used to build the framework for the numerical groundwater fl ow model. Due to the way the geological framework model and the conceptual groundwater model were generated they could not be viewed together; this inevitably led to a signifi cant loss of information and understanding. With the current rapid developments in 3D modelling software and the increasing availability of digital geological data it is now possible to produce detailed 3D geological models of complex aquifer sequences. In this paper we will use two case studies (Chalk aquifer of the London Basin and the Jurassic limestone aquifer of the Cotswolds) to demonstrate that by developing a detailed 3D geological model signifi cant benefi ts are gained in the understanding and development of the conceptual groundwater model.

Using integrated near-surface geophysical surveys to aid mapping and interpretation of geology in an alluvial landscape within a 3D soil-geology framework

An integrated geological, geophysical and remote sensing survey was undertaken as part of the construction of a high-resolution 3D model of the shallow subsurface geology of part of the Trent Valley in Nottinghamshire, UK. The 3D model was created using the GSI3D software package and the geophysical techniques used included ground-penetrating radar (GPR), electrical resistivity tomography (ERT) and automated resistivity profiling. In addition, the remote sensing techniques of light detection and ranging (LIDAR) and airborne thematic mapping (ATM) were used. The objective of the study was to assess the contribution of these techniques to improve the geological mapping and interpretation of terrace deposits and other geological features. The study site had an area of ~2 km2 and consisted of a Triassic mudstone escarpment, overlain first by a sand and gravel river terrace that extended to the modern floodplain of the River Trent. Automated resistivity profiling mapping proved to be the central tool in identifying and positioning geological features at a greater resolution than would be obtained through traditional geological mapping and borehole observation. These features included i) a buried cliff delineating the south-eastern limits of the incised Trent valley, ii) siltstone beds within the Gunthorpe Member of the Mercia Mudstone Group and iii) the variability of the sediments within the river terrace. A long ERT transect across the site successfully imaged the buried cliff and outcropping siltstone beds on the escarpment. Combined ERT and GPR transects revealed the depth of the sand and gravel deposits (Holme Pierrepont sands and gravels), whilst the GPR provided information about the depositional environment. Remote sensing using light detection and ranging proved essential in the original geological survey because it confirmed the absence of a second river terrace that had been previously thought to exist. This case study demonstrates the importance of combining geophysical techniques with traditional geological survey and borehole analysis, in order to create high-resolution 3D geological models, which are increasingly being used as a platform to understand and solve environmental problems.

3D modelling of geology and soils : a case study from the UK

Developments in GIS based technology have greatly aided the routine production of three-dimensional geological maps. Similarly the continued development of airborne remote sensing, geophysics and infrared measurement now provide tools that can assist in the mapping of soil structure and properties rapidly in 2D, 3D and even 4D. Whilst the combined use of such techniques have grown popular for performing site investigations and developing conceptual models of contaminated sites their use in determining and mapping soil has been restricted.

URBAN GEOLOGY: INTEGRATING SURFACE AND SUB-SURFACE GEOSCIENTIFIC INFORMATION FOR DEVELOPMENT NEEDS

The British Geological Survey (BGS) operates an urban geoscience programme that aims to provide up-to-date information on ground-related issues for the towns and cities of the UK. Research in the major conurbations of Manchester, Swansea and Glasgow is demonstrating the value of integrating surface geological mapping with sub-surface geoscientific information through the use of three-dimensional models. This approach provides a more holistic view of the near-surface environment and provides a means of identifying potential problems and opportunities at an early stage in any proposed development. If implemented over a wider area, it could assist in designing site investigation strategies and reduce costs by ensuring a more focused approach to strategic planning.

Model fusion at the British Geological Survey: experiences and future trends

Abstract The British Geological Survey (BGS) is developing integrated environmental models to address the grand challenges that face society. Here we describe the BGS vision for an Environmental Modelling Platform (BGS 2009) that will allow integrated models to be built, and describe case studies of emerging models in the United Kingdom. This Environmental Modelling Platform will be founded on the data and information that the BGS holds. This will have to be made as accessible and interoperable as possible to both the academic and stakeholder decision-making community. The geological models that have been built in an ad hoc way over the last 5–10 years will be encompassed in a National Geological Model that will be multi-scaled, beginning with onshore UK and eventually including the offshore continental shelf. The future will be characterized by the routine delivery of 3D model products from a multi-scaled and scalable 3D geological model of the UK that can be dynamically updated. The deployment of this model will generate further significant requirements across the Information and Knowledge Exchange spectrum, from applications development (database, GIS, web and mobile device), data management, information product development, to delivery to a growing number of publics and stakeholders.

Integrated Environmental Modelling to Solve Real World Problems: Methods, Vision and Challenges

The discipline of Integrated Environmental Modelling (IEM) has developed in order to solve complex environmental problems, for example understanding the impacts of climate change on the physical environment. IEM provides methods to fuse or link models together, this in turn requires facilities to make models discoverable and also to make the outputs of modelling easily visualized. The vision and challenges for IEM going forward are summarized by leading proponents. Several case studies describe the application of model fusion to a range of real-world problems including integrating groundwater and recharge models within the UK Environment Agency, and the development of ‘catastrophe’ models to predict better the impact of natural hazards. Communicating modelling results to end users who are often not specialist modellers is also an emerging area of research addressed within the volume. Also included are papers that highlight current developments of the technology platforms underpinning model fusion.

Introduction to integrated environmental modelling to solve real world problems: methods, vision and challenges

Across the world, stakeholders are asking questions of their governments and decision makers to quantify the risks of environmental threats to their well-being. These questions manifest themselves as ‘deceptively simple questions’, which are easy to articulate but difficult to solve. An example of which is: ‘how much will the eruption of an Icelandic volcano cost the UK economy’. Answering these questions requires predictions of the interaction of multiple environmental processes, this requires the development and maintenance of systems that allow these processes to be simulated, and that is the nascent science of integrated environmental modelling (IEM). Such processes may be long-term (e.g. those that are impacted by climate change) or short-term threats, such as the impact of drought on UK agriculture or the impact of space weather on energy supply systems.