Building high, building deep

Apart from finding riches in the Earth’s crust, Earth scientists also make it possible to build great structures on or in its surface.

About 70% of the world’s population lives in coastal areas – on sandy, clayey and muddy soils at sea level. The geotechnical knowledge of Earth scientists is essential in establishing cities, building industries and constructing dams. Nowadays, as urban populations rise, geotechnical engineers are helping to build safe underground structures like the Channel Tunnel (linking the UK with the rest of Europe), or the subways of Paris or London.

In the near future, humans will be making greater use of the subsurface for living, moving, storage and environmental mitigation. To do this will require knowledge of the Earth System’s response. Subsidence due to mining or lowering of the groundwater table by water extraction, and earthquakes induced by exploitation of natural gas are just a few examples of how human activities in and on the crust may cause adverse effects for which we need to be ready.
Planet Earth in our hands
The changing world of Earth Science
Humans in the landscape
Spheres within spheres
Damming the tide

In Holland, every person can be said to own one metre of dam, 20,000 kilometres of which protect two thirds of the country from flooding. The Dutch government has recently planned several new residential areas in polders at depths varying between 4 and 7m below sea level. Keeping the streets dry will require additional pumping to lower the groundwater in the peat and clay on which the new homes are being built.But this causes subsidence – at a rate of ca. 1 cm per year – which is more than the figure by which average sea levels are rising.

Earth scientists predict that in the next century only massive investments in water management will prevent the Delta metropolis of Amsterdam, Rotterdam and The Hague from drowning. In the next few decades, their knowledge of the geological formations and groundwater flow, the behaviour of the Rhine, Meuse and North Sea, as well as geotechnical aspects of pumping, building and tunnelling, will all be essential to design and implement safe scenarios for Holland’s future.