The project, funded by the German Federal Ministry for Economic Affairs and Climate Action under grant number 03EE4003E, was carried out at the Institute for Geosciences of Friedrich‑Schiller‑University Jena. Its aim was to improve the monitoring and risk assessment of induced seismicity in deep geothermal power plants, with a particular focus on the Landau/Insheim field in the Upper Rhine Graben. The work was conducted from the early 2020s through 2023, with a COVID‑19‑related pause that led to an extension of the project period and additional funding.
The scientific effort was organised into four work packages. The first package investigated depth‑dependent shear‑wave attenuation in two hydrothermal geothermal settings: the Upper Rhine Graben and the Bavarian Molasse. Using a network of four borehole seismometers deployed at depths of a few hundred metres, the team successfully analysed data from two stations (ROTT and LDE) and inverted the attenuation parameters with a genetic‑algorithm‑based solver that was parallelised for a high‑performance computing cluster at Jena. The analysis revealed a clear decrease of attenuation with increasing depth, except for the scattering quality factor (Q^{-1}_{sc}), which showed only a weak depth dependence and even increased at high frequencies. The attenuation behaviour was further characterised by fitting a power‑law model (Q^{-1}=Q_0 f^{-n}), reducing the number of free parameters to two and smoothing the frequency response.
The second package performed a time‑frequency analysis of the recorded micro‑earthquakes. A filter bank of adjacent band‑pass filters was used to compute the energy density as a function of time and frequency. The energy‑transfer theory was applied to estimate local ground‑strengthening effects. This approach allowed the researchers to quantify the frequency‑dependent ground velocities and compare them with the DIN 4150 standard for building‑vibration assessment. The study produced absorption coefficients (b) and transport‑scattering coefficients (g^*) for eight frequency bands across five depth intervals, summarised in a table of values. The results showed that the maximum ground velocity recorded during the 2009 induced event (magnitude 2.7) was within the limits prescribed by DIN 4150, confirming that the induced shaking did not pose a significant risk to nearby structures.
The third and fourth packages, not detailed in the report excerpt, were intended to automate the seismic‑event magnitude estimation and to integrate the monitoring data into a real‑time risk‑management framework. The overarching goal was to reduce the manual effort required for seismic‑event analysis, thereby lowering the cost and time needed to maintain acceptable seismic‑risk levels in operating geothermal plants.
Collaboration within the project involved data sharing with the MAGS and MAGS 2 monitoring networks, as well as the SEIGER project, which provided extended seismic datasets for the Landau/Insheim area. The project’s outcomes demonstrate that automated, high‑resolution monitoring combined with advanced attenuation modelling can effectively constrain the probability of larger induced earthquakes, supporting safer operation of enhanced geothermal systems.