GIS Solution for Mapping the Subsurface

When describing GIS, most users and clients think of mapping features above the ground.  But what about the features below?

Here at AE2S, we can help! By using the Xacto Cross Section Tool, created by the Illinois State Geologic Survey, geologic cross sections can be profiled with precision. When planning engineering projects such as a diversion or monitoring an aquifer, having an accurate subsurface cross section is key.

To utilize the Xacto Cross Section Tool the following data is needed:

  • Elevation raster (DEM) of the ground surface to produce a surface profile
  • Bedrock topology (not essential)
  • Cross section line
  • Either well geologic data or downhole geophysical data (depending on information available or preferred plotting methods)

The results of this process can then be viewed in 2-D or 3-D as seen below.

The figure above shows well logs labeled vertically with the soil types found at various depths. The purple line represents the bedrock profile while the green line is the surface profile. The red lines represent faults.

The figure below is a 3D rendering of the same cross section with the surrounding landscape as a DEM.

By mapping the subsurface with accuracy, we can properly display aquifer related soils which can help to monitor a municipality’s water source and plan for future development of a water distribution system.

What other potential benefits can you think of from creating an accurate subsurface map?