Microseismicity swarm activity in the East Eifel Volcanic Field - A response to magmatic processes?

The East Eifel Volcanic Field (EEVF) in Germany is a densely monitored yet dormant distributed volcanic field comprising hundreds of Quaternary volcanoes, including the most recent eruption of the Laacher See Volcano ~13,000 years ago. The GFZ's Central European Volcanic Province Observatory (CVO) integrates data delivered by multiple partners: Seismic data, GNSS, a superconducting gravimeter, and fluid monitoring sites to detect subtle signals of volcanic and tectonic activity. This study focuses on microseismic swarms observed within the EEVF since January 2020. We present a multidisciplinary analysis of selected swarm sequences, with particular emphasis on their spatial proximity to recently mapped crystal velocity anomalies, interpreted as potential melt reservoirs. Notably, the suspected locations of partial melt reservoirs beneath the EEVF correlate well with the location of the DLF earthquakes. Most recently, a swarm of approximately 120 locatable events (Mw < 1.6) occurred near the Laacher See Volcano in October 2025, prompting considerable public and media interest. Preliminary moment tensor inversion and cross-correlation-based clustering indicate a highly self-similar sequence with oblique normal faulting to strike-slip faulting mechanisms in agreement with the regional stress field. Although the EEVF is not typically characterized by extensive swarm activity, our analysis reveals tens of tiny swarm sequences over the past six years. The Oct-2025 swarm illustrated the feasibility of a quick, multidisciplinary assessment of the EEVF; during this swarm, no co-seismic changes in ground deformation, fluid properties, or gravity were detected. In our ongoing work, we explore several hypotheses linking the microseismic swarms to fluid-driven processes near potential melt reservoirs.