The upper crustal structure of the Eifel volcanic region (southwest Germany) from local earthquake tomography using Large-N seismic network data

This is the authors' abstract. We don't add key points for this paper.

From September 2022 to August 2023, a temporary large-N seismic experiment with more than 494 station locations was conducted in the Eifel volcanic fields of southwest Germany, where massive intracontinental maars and explosive centres are distributed. The last major eruption occurred at the Laacher See volcano (LSV) only 13 ka ago. The exceptional dataset was used to image V P and V P /V S ratio structures with a minimum grid spacing of 2 km. The final results were interpreted with local seismicity and other geophysical data. In addition to major tectonic features, our 3-D tomographic models resolve the LSV reservoir-structure between 2 and 10 km depth with high V P /V S anomaly. The cylindrical anomaly has a volume of approximately 75 km 3 and dips 40° to the southeast, where it crosses the Siegen thrust at a depth of about 10 km. Micro-earthquakes cluster at the margins of the high V P /V S - low V P anomalies, indicating that the zones are under high fluid pressure or elevated temperatures. This anomaly is also located above the crust-mantle seismic channel, characterized by deep low-frequency volcanic earthquakes at depths of 10 km to 43 km, suggesting that the anomalous zones may be related to the migration of magmatic fluids.