Preliminary imaging of the Eifel Volcanic Field from seismic scattering

The Eifel region (southwest Germany) is an intracontinental volcanic field of distributed explosive centers, with the last major eruption occurring at the actively degassing Laacher See volcano in 13ka. The temporary Eifel large-N seismic network was deployed here between September 2022 and August 2023, which significantly increased station coverage allowing for a detailed study of the subsurface magmatic system. We use local earthquakes to study the attenuation properties of  the subsurface structure, targeting Laacher See volcano and its surroundings. 

Starting with an automatically derived earthquake catalog, we first perform a number of quality checks to ensure we only use the cleanest waveform traces and picks. Then, we estimate scattering from peak-delay measurements, i.e. the delay of the maximum energy after the S-wave. Our preliminary findings suggest the presence of two upper crustal structures beneath Laacher See, outlined by areas of high scattering, which are typically associated with the presence of small-scale heterogeneities or mechanical discontinuities (e.g. fractures, faults) and range from the surface to 8 and 13 km below sea level. Their proximity to Laacher See suggests that the rise of fluids may be facilitated by these structures. Further analysis will have to show whether the data can also be used to quantify absorption, which would shed even more light on fluid pathways.