The ICT infrastructure that LOFAR will give rise to holds great potential for non-radio astronomers, enabling them to make strides in monitoring at an accelerated pace. In the geosciences field, it should be possible, for example, to extend the understanding of natural and induced seismicity, subsidence, and water management. The TU Delft, the Royal Dutch Meteorological Institute (KNMI) and TNO-NITG are participating in the application of LOFAR in the geosciences.

The advanced network of fibre optics will transport also geoscientific measurement data. The following are some of the activities the geoscientific participants in the consortium will be involved in:

- Seismic applications
- Infra-sound applications
- GPS/INSAR applications on subsidence
- Groundwater monitoring
- Pressure and temperature monitoring

Seismic Applications

Research projects

Distribution of seismicity in the Netherlands (source: VU Amsterdam and KNMI).

Recording natural seismicity by linking vibration sensors to the LOFAR network. This will mean using groups of multi-component motion sensors that will permanently monitor the seismic activity at the various LOFAR locations. Of particular interest will be areas subject to recent seismic activity.

Monitoring induced seismicity, for example as a result of gas extraction with the ultimate goal of linking observed seismicity to reservoir processes.

Monitoring reservoir characteristics via passive and active seismic observations taken with the seismic sensor networks mentioned above. The passive seismic response – i.e. the seismic observations made without explicit use of a seismic source – will be converted into a ‘reflection seismic response’ using daylight imaging techniques.

Monitoring the seismic receiver response functions. It may be possible to relate a changing response from seismic sensors to change in the elastic characteristics of the shallow subsurface and to fluctuations in the water table.

Two Seismic sub-networks

Parallel to the installation of antennas on the LOFAR fields, seismic sensors will be placed on those fields. These sensors will mainly be used for recording the natural seismicity and monitoring the response functions of the seismic receivers. The Meteorological Institute will manage these seismic data. This data-management is driven by events, mainly earthquakes.

Monitoring of reservoir characteristics requires a denser spatial sampling than the LOFAR fields. Therefore 2 arrays of some 4-kilometer lengths are planned with seismic sensors being placed every 25 meters. Somewhere along the arrays of seismic receivers, the line will connect to a LOFAR antenna-filed, and there the data will be put onto the network and subsequently be stored by the Netherlands Institute of Applied Geoscience TNO. This data-management is focussed on storing all continuous data (with low-loss data-compression).

Infra-sound applications

Using infra-sound arrays to detect all kind of processes that generate these waves, such as nuclear blasts, volcano eruptions, etc.

GPS/INSAR applications on subsidence

Monitoring subsidence. By linking GPS stations to LOFAR and the combination of GPS observations with, say, INSAR height measurements, a detailed picture can be obtained of regional and local subsidence. Where subsidence occurs in the vicinity gas fields, it may be possible to study the relationship with induced seismicity.

< Subsidence in the north of the Netherlands.

Groundwater monitoring

Linking (parts of) the groundwater monitoring network to LOFAR to enable the ‘real-time’ monitoring of groundwater levels.

Subsurface-pressure and -temperature monitoring

Linking subsurface sampling to LOFAR. This would involve, say, placing in-situ pressure and temperature sensors in boreholes, pre-existing ones or those drilled for this purpose.

< GO BACK

In case of questions or comments regarding LOFAR, or about these web pages, please contact lofar@astron.nl
Read this disclaimer before proceeding.

Jobs | Pictures | Publications | Archives | Sponsors