Lusatia – Gateway to the stars

06.12.2024

„Lusatia’s treasure“, this is how scientists at the German Center for Astrophysics (DZA) describe the large, uninterrupted granodiorite massif in the underground of Saxonies Upper Lusatia. While still in its founding phase, the DZA aims big: an underground laboratory within the massif, the Low Seismic Lab (LSL). The goal is to create an environment of zero seismic noise to operate susceptible detectors and conduct pioneering experiments in astrophysical research. But will „Lusatia’s treasure“ meet these requirements?

To find the answer to this question, scientists from different disciplines in earth sciences across Germany have come together under the auspices of the DZA.

Geologists at Freiberg University of Mining and Technology (TUBAF) and the Saxony State Service are diving into the state’s mining history. During the past century, thousands of drillings were conducted, mapped, and evaluated to extract raw materials for the industry. These boreholes are now reanalysed with a focus on the requirements of the LSL. The aim is to create a high-resolution, three-dimensional geological subsurface model to find the best possible location for the laboratory in the rock.

Seismologists at TUBAF, German Research Centre for Geosciences (GFZ), and Karlsruhe Institute of Technology (KIT) are interested in the physical properties of the underground and the permanent ambient noise in Lusatia. Physical parameters, like seismic velocities, give insight into the strength of the rocks which is crucial information for later excavation works.
Noise on the other hand is mainly attributed to anthropogenic activities such as city life, roads, or wind turbines. Long-term passive experiments at the Earth’s surface and in boreholes help to better understand their influence and identify particularly quiet places. Especially measurements in the borehole provide direct information about the unrest at the target depth of future laboratory. Further boreholes will hence follow, geologically mapped, instrumented, and geomechanically examined at Fraunhofer IEG.

Preliminary results map a very positive picture for Lusatia. The rock massif is likely larger than previously assumed and the long-term measurement in the borehole shows low noise levels in the study area, independent of the season.

The Free State of Saxony is therefore going one step further and aims to bring the Einstein Telescope (ET) to Lusatia in addition to the DZA’s LSL. Lusatia is now positioning itself as a third candidate site, alongside the Island of Sardinia and the tri-border region Euroregion Meuse-Rhine, to host this major European project. Studies on the LSL and its requirements hereby follow the ET guidelines. The large-scale investigations can therefore be incorporated directly into the site characterization for ET.

Involved partners of the Lusatian site investigation team alongside the DZA (supported by TU Dresden and DESY) are:
TUBAF – Freiberg University of Mining and Technology
GFZ – German Research Centre for Geosciences
KIT – Karlsruhe Institute of Technology
IEG – Fraunhofer Research Institution for Energy Infrastructures and Geothermal Systems