@article{DahmStillerMechieetal.2020,
  author    = {Dahm, Torsten and Stiller, Manfred and Mechie, James and Heimann, Sebastian and Hensch, Martin and Woith, Heiko and Schmidt, Bernd and Gabriel, Gerald and Weber, Michael},
  title     = {Seismological and geophysical signatures of the deep crustal magma systems of the cenozoic volcanic fields Beneath the Eifel, Germany},
  series = {Geochemistry, geophysics, geosystems},
  volume    = {21},
  journal   = {Geochemistry, geophysics, geosystems},
  number    = {9},
  publisher = {American Geophysical Union},
  address   = {Washington},
  issn      = {1525-2027},
  doi       = {10.1029/2020GC009062},
  pages     = {21},
  year      = {2020},
  abstract  = {The Quaternary volcanic fields of the Eifel (Rhineland-Palatinate, Germany) had their last eruptions less than 13,000 years ago. Recently, deep low-frequency (DLF) earthquakes were detected beneath one of the volcanic fields showing evidence of ongoing magmatic activity in the lower crust and upper mantle. In this work, seismic wide- and steep-angle experiments from 1978/1979 and 1987/1988 are compiled, partially reprocessed and interpreted, together with other data to better determine the location, size, shape, and state of magmatic reservoirs in the Eifel region near the crust-mantle boundary. We discuss seismic evidence for a low-velocity gradient layer from 30-36 km depth, which has developed over a large region under all Quaternary volcanic fields of the Rhenish Massif and can be explained by the presence of partial melts. We show that the DLF earthquakes connect the postulated upper mantle reservoir with the upper crust at a depth of about 8 km, directly below one of the youngest phonolitic volcanic centers in the Eifel, where CO(2)originating from the mantle is massively outgassing. A bright spot in the West Eifel between 6 and 10 km depth represents a Tertiary magma reservoir and is seen as a model for a differentiated reservoir beneath the young phonolitic center today. We find that the distribution of volcanic fields is controlled by the Variscan lithospheric structures and terrane boundaries as a whole, which is reflected by an offset of the Moho depth, a wedge-shaped transparent zone in the lower crust and the system of thrusts over about 120 km length.},
  language  = {en}
}
@article{HenschDahmRitteretal.2019,
  author    = {Hensch, Martin and Dahm, Torsten and Ritter, Joachim and Heimann, Sebastian and Schmidt, Bernd and Stange, Stefan and Lehmann, Klaus},
  title     = {Deep low-frequency earthquakes reveal ongoing magmatic recharge beneath Laacher See Volcano (Eifel, Germany)},
  series = {Geophysical journal international},
  volume    = {216},
  journal   = {Geophysical journal international},
  number    = {3},
  publisher = {Oxford Univ. Press},
  address   = {Oxford},
  issn      = {0956-540X},
  doi       = {10.1093/gji/ggy532},
  pages     = {2025 -- 2036},
  year      = {2019},
  abstract  = {The occurrence of deep low-frequency (DLF) microearthquakes beneath volcanoes is commonly attributed to mass transport in the volcanic plumbing system and used to infer feeding channels from and into magma reservoirs. The key question is how magmas migrate from depth to the shallow crust and whether magma reservoirs are currently being recharged. For the first time since the improvement of the local seismic networks in the East Eifel region (Rhineland-Palatinate, Germany), we detect and locate recurrent DLF earthquakes in the lower crust and upper mantle beneath the Laacher See Volcano (LSV), using a joint data set of permanent sensors and a temporary deployment. So far, eight DLF earthquake sequences were observed in four distinct clusters between 10 and 40 km depth. These clusters of weak events (M-L< 2) align along an approximately 80. southeast dipping line south of the LSV. Moment tensor solutions of these events have large shear components, and the irregular dispersion and long coda of body waves indicate interaction processes between shear cracks and fluids. We find a rotation of P-axes orientation for shallow tectonic earthquakes compared to DLF events, indicating that the stress field in the depth interval of DLF events might favour a vertical migration of magma or magmatic fluids. The caldera of the LSV was formed by the last major eruption of the East Eifel Volcanic Field only 12.9 kyr ago, fed by a shallow magma chamber at 5-8 km depth and erupting a total magma volume of 6.7 km(3). The observed DLF earthquake activity and continuous volcanic gas emissions around the LSV indicate an active magmatic system, possibly connected with an upper mantle melt zone.},
  language  = {en}
}
@article{DahmKruegerEssenetal.2005,
  author    = {Dahm, Torsten and Kr{\"u}ger, Frank and Essen, Heinz-Hermann and Hensch, Martin},
  title     = {Historic microseismic data and their relation to the wave-climate in the North Atlantic},
  year      = {2005},
  abstract  = {Microseismic data from observatories in Europe, which have been continuously recorded since about 100 years, contain information on the wave-climate in the North Atlantic. They can potentially be used as additional constraints in high-resolution temporal and spatial reconstructions of the storminess and oceanic waveheights in the past. To resolve spatial patterns data from observatories in different regions are needed. While previous recent studies analyzed only few observatory archives and relatively short time ranges, this is a first attempt to process the whole available data archive from different observatories. We correct and compare smoothed microseismic data from different stations and discuss their correlation and possible use for studies of storminess variability. Microseismic amplitudes at four seismic stations in northern Europe show amplitude peaks in 1920 and 1925, a slow decline in amplitudes till the middle of the 1930's followed by a steady increase of amplitudes till about 1990. From 1990 on microseismic amplitudes decrease. We find a good correlation between the average surface wind velocity in the North Atlantic and microseismic amplitudes at inland stations far away from the coast. Coastal stations are more influenced by local swell and are thus potentially useful to recover regional changes in wind and ocean wavefields with time. The study demonstrates that the analysis of microseismic has the potential to assess climate changes during the last 100 years},
  language  = {en}
}