Areas of application

The great interest in geoscience is larely motivated by the desire for the use of the subsurface space, subsurface natural resources and concern about the subsurface environment and geo hazards.

The natural resources that occur underground concern especially minerals. The subsurface space concerns the possibilities of utilizing the underground for infrastructure and for storage. In the Netherlands the most important aspects relating to the subterranean environment have to do with the pollution of the subsurface and groundwater, and also the environmental aspects of using the subsurface and its natural resources. The geo hazards in the Netherlands are largely subsidence due to the pumping of groundwater or production of hydrocarbons, earthquakes (natural or man-induced) and sea level rise and the risk of flooding.

Geo resources

The Netherlands has abundant underground natural resources. They include natural gas, oil, coal, rock salt, groundwater, geothermal energy and surface minerals. The overexploitation of natural resources (which can result, for example, in a fall in groundwater levels) must be avoided, as must be the premature abandonment of gasfields.

Utility companies (such as the water supply companies) and industry (particularly the manufacturers of construction materials, the groundwater abstractors, the petroleum companies and the chemical industry) are largely responsible for the exploration and the exploitation of the natural resources in the Netherlands.

Geo space

The very shallow subsurface is increasingly used for infrastructural facilities such as foundations, pipelines, storage tanks, tunnels, utility facilities and so on. The technique for installing infrastructure in the soil and subsurface fall in the domain of geotechnical engineering which is an important component of civil engineering.

The subsurface can also be used for the storage of energy (i.e. cold, heat, compressed air, natural gas, oil) and energy wastes (e.g. carbon oxide in sandstone, nuclear waste in rock salt) and chemical waste products.

Geo environment

In many locations subterranean Netherlands, including the groundwater, is polluted as a result of a range of human activities. The use of the subsurface and its natural resources can also lead to environmental pollution on land and in the North Sea.

Geoscientific expertise, methods, products and systems are applied to establish whether pollution is anthropogenic and to what extent remediation is necessary. Small-scale groundwater flow systems can be manipulated and equipped with monitoring systems, and the permeability pattern of the subsurface can be influenced by chemical means. The application of such geoscientific concepts allows subsurface compartments to be isolated, enabling in situ remediation of polluted soil, deeper layers and the groundwater. In addition, large-scale systems can also be modelled, so that the behaviour of pollutants can be predicted.

Dutch society (public, semi-public and private organizations) is held accountable for preventing environmental pollution. The national government and provincial and local authorities determine where remediation is necessary, its urgency , and how it should be implemented. They do it on the basis of research and advice. The remediation is carried out by specialized companies.

Geo hazards

Over large parts of the Netherlands the ground is subsiding as a result of natural, long-term tectonic processes and human activities. The most important man-induced reasons for the subsidence are drainage, groundwater abstraction, and the exploitation of gas, oil and other minerals (e.g. salt and coal). Accompanying the subsidence is a rise (relative and absolute) of sea level. These phenomena have important long-term impacts on the entire Dutch coastal area and on coast-forming processes – particularly on the formation of beaches and dunes as protection against the sea – and for upwelling of salt water further inland. The construction of sea works has clear short-term effects on the coast, accelerating deposition in some places and erosion in others. Earthquakes occur on a limited scale in the Netherlands. They may have a natural, tectonic cause (e.g. the tremors felt near Roermond on 13 April 1992) or may be triggered by human activities.

Aerospace cartography

The technology of the analysis of aerospace data is designed for the assessmsnt, forecasting of the conditions, and rational use of water and land resources, as well as for the substantiation of specific design solutions.

Main directions in the use of aerospace data

Assessment of reclamative and engineering geological conditions of a territory to substantiate designs of renovation and construction of land reclamation and hydraulic systems.

Assesment of water resources, possibilities of their regulation and recharge to solve problems of water management, power engineering, industrial and domestic water supply.

Assessment of pasture conditions to plan their watering and productivity improvement.

Assessment of erosion processes to plan soil protectiom measures.

Assessment of emvironment to plan nature protection measures.

The technology of the analysis of aerospace data is realized as a series of special thematic maps: hydrogeological –reclamative zoning, soil reclamative , geobotanic, fodder producing areas, specialization of agricultural production, zoning by drainage and heavy leaching parameters, zoning by water duty, assessment of water resources quality, assessment pf groundwater resources and areas of their potential use.

The use of the technology of the analysis of aerospace data makes it possible to reduce the period of designing and scope of ground surveys and to improve the quality of designs.

Different applications of permanent GPS observations

Currently permanent GPS observations are mainly used for the following purposes:

18. Determination, accuracy improvement and maintenance of the ITRF (International Terrestrial Reference Frame). These tasks are carried out nowadays by two global services: IGS (International GPS Service for Geodynamics) whose performance is based on a network of permanent GPS stations and IERS (International Earth Rotaton Service) which uses GPS measurements as complementary to observations made by other satellite and space techniques, mainly by Satellite Laser Ranging (SLR) and by Very Long Baseline Interferometry (VLBI). The most important products offered by these services include precise orbits of the GPS satellites, precise positions of permanent stations (and their velocity vectors) and geodynamic parameters of the Earth rotation; they also provide us with clock corrections of GPS sastellites and tracking stations as well as with information on the ionosphere and troposphere.

19. Establishment of reference control networks (stations) for the connection of the national geodetic frames and newly created national active positioning and navigation systems. Points of the European Reference Frame and permanently working satellite stations that belong to the IGS and IERS services constitute the basic international (global and regional) frame in Europe to which all national satellite control networks are connected.

National active positioning and navigation systems based on permanent

reference stations operating in some countries are known as so-caled Precise Active Positioning System and Standard Active Positioning System. A growing demand for active systems for land, marine and air navigation has been expressed by public services such as aviation, navy, transport, communication, police, fire department, health and other emergency services. This demand is satisfied by the satellite services of DGPS (Differential Global Positioning System) performing their activity in many countries and providing position of moving objects in real time.

20. Establishment of points (stations) for geodynamic research and

connection of local geodynamic networks. The new philosophy of geodynamic research consists in analyzing permanent precise GPS observations that are performed at geodynamic points (in observatories). This helps to detect geodynamic effects including the periodical ones which occur with various amplitude and various frequences (with different periods). Today analysis of changes in the velocity vectors of permanent stations constitutes the basis for the most valuable global and regional geodynamic research. A network established in Japan can serve as an example of this kind of geodynamic network. The Japanese network consisting of 900 permanently operating stations monitors all the short-term changes in the position and provides data for geodynamic interpretation and predictions in relation to possible occurrence of an earthquake.