THE ROLE OF GEOLOGICAL FRAMEWORK MODELS IN UNDERPINNING ENVIRONMENTAL EARTH SCIENCE

The UK's Natural Environment Research Council (NERC), as the parent body of the British Geological Survey (BGS) has defined the following strategic goals:

•           to enable society to respond urgently to global climate change and the increasing pressures on natural resources, and

•           to contribute to UK leadership in predicting the regional and local impacts of environmental change from days to decades;

Both these goals challenges rely on a thorough understanding of the Geosphere e.g. the sub-surface distribution of rocks and soils, their properties and the movements and interaction of solids and fluids therein. The traditional outputs from Geological Survey Organisations such as maps, reports and databases are usually not sufficient to meet these interdisciplinary challenges, as they are often in the wrong format, at an inappropriate scale, limited to two dimensions or simply only deal with a single scientific theme.

From 1990 to 2000 the BGS digitised its entire data holdings (maps, boreholes) and organised them into easily accessible and interoperable formats and databases. National coverage was licensed for a Digital Terrain Models and air photography. In 2000 the decision was taken to begin the migration of the organisation and its outputs from an analogue mapping to a digital modelling “culture”. One of the main outcomes from the research effort during this migration was the development of the GSI3D software and methodology which is now deployed across the organisation enabling all BGS's survey and investigative geologists to construct 3D geological framework models.

GSI3D is designed for the geologist or geoscientist, rather than the highly trained expert software user. The model is built by enabling the user to construct traditional cross sections by correlating boreholes and outcrop data to produce a network of sections, or geological fence diagram. Together with a suitable digital elevation model, this geological interpretation is then used by the software engine to produce a 3D solid model of the subsurface. For the user this is a single click operation. The resulting “geological framework models” are the simply the extension of the 2D geological map and its units into 3D. This is the first stage in answering many the goals set out above.

Fig. 1 The London Geological Framework Model

The challenge now is to populate these geospatial models with properties and establish closer links to process models such as groundwater flow models and engineering design models. Last but not least the resulting models and scenarios need to be put into context with the real world, such as buried infrastructure, tunnels, houses) in order to communicate and disseminate them to other scientists and most importantly the end users of our science such as planners and politicians. Finally we believe one of the greatest values of these models will be in teaching students and the general public about what lies beneath their feet, thereby ensuring public buy-in and understanding of the scientific challenges that lie ahead.

Fig. 2 Integration of geological framework model with other spatial datasets

Acronyms

BGS      British Geological Survey

NERC  Natural Environment Research Council

DTM    Digital terrain model