The subsurface is an important constituent of the physical environment of cities. We live on top of it; building and construction have to deal with the structure and properties of the subsurface, and occasionally with the hazards it presents. Cities not only expand outward and upward, but also downward. More and more, subsurface space is used to relieve the increasingly crowded and congested urban surface, especially for networks (metros, tunnels, cables, sewage, drainage), storage (warehouses, cellars, parking lots, thermal energy), and exotic applications such as shelter and protection (nuclear bunkers, bank vaults, underground passageways in cities with harsh climates). The more use we make of subsurface space, the more surface space we free for the one function that cannot do without daylight and fresh air: living.

Its ability to record is a function of the subsurface that is particularly relevant to the urban domain. Just as rocks in general are records of conditions and events in the geological past, the urban subsurface can be seen as a physical record of the history of cities. Buried cultural heritage needs our protection, whether by preventing its degradation in situ, or by careful excavation before building and construction take place. However, it also reflects industrial legacies and their impacts in the form of polluted soils or unstable mine shafts.

From the above, the importance of knowing the ground beneath cities may seem self-evident, but the urban subsurface is in fact still largely ‘out of sight, out of mind’. It does not present a daily concern to city planners and managers, and when it does, there is often trouble. COST Action TU1206 Sub-Urban therefore sets out to explore, promote and improve the use of the urban subsurface. It aims to help identify options for cities to grow and develop more sustainably that are currently overlooked, and to increase the predictability of ground conditions that are now considered unforeseeable. For these purposes, this report offers a review of the state of the art, which describes the interactions between urban and subsurface domains in generic terms, with special reference to the acquisition of subsurface data, their interpretation into useful subsurface models, and the transferability of data and models to planning documents.

Read more in the summary report Out of sight Out of mind? 


City; urban planning; urban geology; subsurface; A Coruña; Bergen; Dublin; Glasgow; Hamburg; Helsinki; Ljubljana; Nantes; Novi Sad; Odense; Oslo; Rotterdam; Europe.


Michiel van der Meulen

WG1 Leader

Geological Survey of the Netherlands (TNO-GSN)

ingelöv eriksson

WG1 co-Leader

Agency for Planning and Building Services, Oslo city