Wednesday, 27 March 2013

The state of the art in geological information, but how certain are our models?

Here's your chance to find out....

Conventionally geologists have reported surveys as two-dimensional (2-D) maps, such as the one below.   A map like this might be useful to predict the surface geological unit at some location, but geological units are three-dimensional (3-D) subsurface objects.  Would a map be useful if we were planning to dig a tunnel along the route shown by the yellow line, and needed to know what units it might pass through?
In fact geologists have always understood rocks in three dimensions, and the 2-D map is based on 3-D understanding.  Computer software now allows the geologists 3-D understanding to be captured, stored and presented as a 3-D model.  The picture below shows an “exploded” view of some units in the region represented on the map (the colour coding is the same, the model is viewed from near the top right corner of the map).  

A 3-D geological model can be interrogated to identify the geological unit that is expected at a particular location in 3-D, or to compute the total volume of a unit within a region.  This may be useful for engineers, for the evaluation of mineral resources or for planning a tunnel. However, one might reasonably ask how confident we are in these predictions.  This is a growing area of research at BGS, and we will be presenting some results at the forthcoming meeting of the European Geosciences Union. 
Quantifying the uncertainty in 3-D models, from various sources, is of particular importance for BGS and for the geological profession as a whole.   Can we describe the uncertainty in a 3-D model quantitatively so that the risk can be rationally managed?  To address this question we have set up a Ph.D. project jointly with the University of Aberdeen.  The problem is exciting and demanding.  The student who undertakes it will participate in cutting-edge research and will gain experience that will position them strongly for a career in many areas of earth science.
Are you are an enthusiastic, highly numerate individual with an upper second or first class Honours degree in Geology, Geophysics, Physics, Statistics or Maths?  Do you have an aptitude for computing and statistical analysis, combined with survey design and communication?  If so then this opportunity might be for you. 
For informal discussion contact Dr Clare Bond at Aberdeen University or Dr Alison Monaghan or Dr Murray Lark at the British Geological Survey. 

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