Seismic monitoring
Seismic monitoring is a key component of the DeepStor project and goes beyond the standard requirements for projects of this type. To provide comprehensive monitoring and, at the same time, support research into advanced seismic monitoring methods, several complementary sensor technologies are being combined: high-precision seismometers, vibration sensors installed in buildings, mobile sensors, and fiber-optic sensing.
The seismic monitoring concept is based on applicable recommendations and legal requirements. A local network of five highly sensitive seismometers has been established to continuously and independently assess the seismic activity associated with the project. In parallel, three vibration sensors have been installed in particularly sensitive research facilities. Their purpose is to detect vibrations that could potentially interfere with ongoing experiments and research activities at KIT. The recorded data feed into a so-called traffic-light system, which enables a rapid response to unusual ground vibrations and defines the thresholds at which measures must be taken within the project. These measures are intended, for example, to prevent vibrations from affecting sensitive laboratory equipment. Given the proximity of particularly sensitive buildings and research facilities on the KIT Campus North, the DeepStor monitoring concept goes beyond usual requirements. The thresholds for structural vibrations are defined down to 0.03 mm/s, significantly below the commonly cited human perceptibility threshold of approximately 3 mm/s.
The high-precision seismometers are complemented by a dense network of plug-and-play geophones, known as Raspberry Shakes, distributed throughout buildings on the KIT Campus North. These sensors are installed with the voluntary participation of KIT employees as part of a participatory monitoring approach. The data are made publicly available (here) and provide an additional, dense spatial coverage of the campus. A daily updated assessment of the seismic background-noise conditions is also available, providing an overview of the recording conditions at each station.
A third component of the monitoring concept is based on fiber-optic sensing. This unconventional sensing technology is being investigated in the framework of DeepStor in collaboration with the RUBADO project. The work is made possible in part through the use of infrastructure established as part of the Chem4Quant Cluster of Excellence for research into the chemical design of high-precision quantum architectures. An existing fiber-optic telecommunications connection on the KIT Campus North, extending to the South Campus, is being used to further develop methods for exploiting operational telecommunications fiber networks for seismic monitoring. This approach will be further extended to the DS-1 exploratory well, with two fiber-optic cables installed along the well to enable the monitoring of seismicity directly along the borehole and closer to the target region at depth. In addition to seismic signals. The fiber-optic cables will also provide distributed measurements of key parameters such as temperature and strain.
An overview of the currently installed monitoring infrastructure—including seismometers, Raspberry Shakes, and fiber-optic cables—can be found here.
Contact: Dr. Jérôme Azzola