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 CO₂ 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.

| Geochemistry Geophysics Geosystems (G3), 21, 9 | DOI: https://doi.org/10.1029/2020GC009062 |

We used 7-decade-long photogrammetric data acquired over Bezymianny volcano, Kamchatka, to document a rebirth of a new volcanic edifice after the 1956 sector collapse. Thus we revealed all morphological changes, identified three main stages of the new edifice development, and detected a gradual vent centralization that can be related to loading changes, affecting magma pathways at depth. The calculated long-term growth rate allowed us to estimate the regain of the pre-collapse size of the volcano within the next 15 years. This work, for the first time, sheds light on the complex regrowth processes following sector collapses of volcanic edifices.

| Communications Earth & Environment, 1, 15 | DOI: https://doi.org/10.1038/s43247-020-00014-5 |

Since 1991, induced earthquakes are observed in connection with gas production in the Groningen field (The Netherlands). We introduce a method for probabilistic source mechanism estimation and demonstrate its use based on a single event within the Groningen field with the aim to derive rules of good practice for this region. By using full waveforms, we avoid difficulties in identifying seismic phases. Employing a probabilistic approach, we map uncertainties in the solution, which are commonly rarely reported. In addition to the source mechanism, event locations are provided, potentially allowing to relate earthquakes to specific faults. The analysed event shows traits of an implosion and may be interpreted as normal fault and collapse at reservoir level.

| Bulletin of the Seismological Society of America, 110, 5, 2095-2111 | DOI: https://doi.org/10.1785/0120200099 |

An earthquake generates a sudden rock-mass redistribution through fault rupture and generates seismic waves that cause bulk density variations propagating with them. Both processes induce perturbations in the gravity potential field whose signals propagate with the speed of light and therefore can arrive at remote stations earlier than the fastest elastic wave. In turn, the gravity perturbations generate secondary seismic sources everywhere within the earth, a part of which around the station can cause ground motion prior to the direct seismic wave arrival there, too. Recently, these so-called prompt elasto-gravity signals (PEGS) of large seismic events like the 2011 Mw 9.1 Tohoku earthquake have been detected using the data recorded by broadband seismometers and superconducting gravimeters. Though the physics of the PEGS has been well understood, the tools used so far for a realistic modelling of them are complicated and computationally intensive. In this study, we present a new and straightforward approach that solves the full-coupled elasto-gravitational boundary-value problem more accurately, but no more complicated than to compute synthetic seismograms in a conventional way. Using the new tool, we simulate the complete PEGS of the 2011 Tohoku earthquake based on a kinematic finite-fault source model. Furthermore, we discuss the implications and the potential uses of PEGS in modern seismology. As an example, we show particularly that the major source parameters like the moment magnitude, the rupture duration and the focal mechanism of a megathrust earthquake can be estimated robustly using the measured PEGS data.

| Earth and Planetary Science Letters, 536, 116150 | DOI: https://doi.org/10.1016/j.epsl.2020.116150 |