Description
From 2022 to 2023, we initiated and coordinated a community lighthouse experiment in the Eifel volcanic fields, deploying over 500 seismic stations. The initial analysis of this unique dataset produced a list of remarkable findings, including the first high-resolution image of the location, size, and depth of the upper crustal reservoir of the Laacher See volcano (LSV), which produced a VEI 6 eruption only 13,000 years ago. We mapped the upwelling of the crust-mantle boundary (Moho) by 5 kilometers and the lithosphere-asthenosphere boundary (LAB) by 25 kilometers at high resolution. This indicates that the channel of deep, low-frequency (DLF) earthquakes beneath the LSV crosses the upwelling layers at their highest points. Preliminary analysis of seismograms from crustal earthquakes revealed strong local S-to-P reflections in the lower crust beneath the LSV. Based on their extent and nature, these reflections indicate the presence of at least one large horizontal sill reservoir at a depth of 25 km in the lower crust beneath the neuwied basin where magma is stalled. Smaller sill reservoirs are indicated at shallower depths of 20 and 15 kilometers. These sills may have occasionally supplied the upper-crustal phonolite reservoir of the LSV, maintaining its thermal state for tens of thousands of years prior to the last eruption. The 12-month postdoctoral project aims to develop better mapping, characterization, and monitoring approaches for the sills that feed the LSV volcano. This information will be key for planning the ICDP Eifel shallow and deep wells.