The Full Picture

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European geological surveys and GEOSS –

observing the Earth beneath our feet:

why does it matter?

Patrice Christmann, Secretary-General, EuroGeoSurveys

hile the atmosphere and the Earth’s surface are acces-

sible to direct observation including by remote sensing

techniques, the observation of the Earth’s subsurface,

its related resources and hazards require the use of comple-

mentary observation techniques. Many of these are of an

indirect nature, such as the cartography of the various physical

properties of the subsurface (geophysics).

Geology is all about understanding, mapping and modeling the

Earth’s subsurface nature, structure and dynamics, and its related

resources and hazards. It is also the forensic science needed to

understand our Earth’s long and turbulent past. The resulting spatial

data, information and knowledge are needed to better address soci-

etal issues of today and tomorrow such as climate change,

sustainable use of natural resources, land-use planning, manage-

ment and storage of waste, mitigation of the impacts of natural

hazards of geological origin, identifying public health issues and

many more.

An ever-growing number of Earth observation techniques is avail-

able to geologists to produce the information required by the wide

range of end users of geological information, ranging from the macro

scale, such as the use of remotely sensed data and/or direct in situ

observations and mapping, to the nano scale, such as isotopic

geochemistry needed to determine the age of rock formations, or

electronic microprobe studies of mineral grains to develop the tech-

nologies best suited for the efficient recovery of the valuable metals

content from an ore body. Geological data describing the nature,

structure and ages of superficial formations and bedrock formations

is in most cases a fundamental geographic data layer necessary, in

combination with other data layers, to produce the information

required by end users.

In addition to technologies, considerable human skills are neces-

sary to select the right data sources and to steer/implement the data

acquisition process, which in many cases requires direct observa-

tion in the field, and afterwards to do the combinatorial processing

and modelling of heterogeneous Earth observation datasets.

Processing and modelling by experienced scientists is necessary to

turn raw Earth observation data, which is meaningless to most end

users, into the geographic information required to address end users’

concerns. The whole process is steered by specific end uses, each

requiring the use of different data sources and processing/model-

ling techniques. For instance, the process involved in developing

geographic information necessary to mitigate the potential impacts

of landslides is very different from the process involved

in generating information to guide mineral exploration

or sustainable groundwater management. Therefore,

geological surveys are institutions populated by scien-

tists from a wide range of complementary disciplines,

working together to deliver high-quality geographic

information to end users.

Understanding and mapping the subsurface and

providing the derived geographic information to end

users is essential to the global economy and to social

well-being. The underground is home to many

resources that are essential to life: energy (fossil and the

clean, renewable, dependable geothermal energy),

groundwater (the main source of drinking water supply

in many countries) and minerals (the main material

flow across the world economy).

Subsurface also means space to develop a wide range

of infrastructures, and storage for gas, waste or water.

Geology also has a strong incidence on the nature and

fertility of soils. The chemical elements in rocks deter-

mine the chemical composition of the groundwater they

host, of soils derived from their weathering and, from

this, the chemical elements found in our food and

drinking water. Excess or deficit of certain of these

elements can significantly impact health.

The subsurface and its dynamics are also the source

of many natural hazards. Some, such as earthquakes,

landslides or volcanic eruptions are spectacular and

hence are easily perceived by public authorities. Some

are more subtle and difficult to notice before their

economic and social impacts become visible: among

these are land heave and subsidence, gaseous emana-

tions (radon gas emanations are considered in various

epidemiological studies as an important source of lung

cancer), caving-in of man-made or natural cavities, and

shrinkage and swelling of clay-rich soils (costing

billions of euros to insurance companies compensating

the resulting damage to buildings).

Access to and sustainable use of natural resources of

geological origin, and mitigation of the impacts of

natural disasters of geological origin, will be issues of

growing importance – the Earth’s population is set to

reach nine billion in 2050, and the populations of

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