The Campi Flegrei volcano in Italy displays hot fumarolic solfataras famous since Roman times. We use the solfataric mineralizations to investigate the local setting, evolution and geohazards. These provide information on hydrothermal activities that have been stable over the past 20 years. They reflect extreme conditions associated with the fluid overflow from subsurface and surface waters through a fracturing conduit. The solfataras are toxic and represent an extreme environment for life.

We present a workflow that combines different geophysical techniques, showing that a detailed seismic velocity model can be obtained even for non-optimal data sets, i.e. relatively short-offset, band-limited streamer data recorded in deep water. This fact has an important implication for the Marine seismic community, suggesting that many of the existing data sets should be revisited and analysed with new techniques to enhance our understanding of the subsurface, as in the Alboran Basin case.

A new code for anisotropic travel-time tomography is presented. We describe the equations governing the anisotropic ray propagation algorithm and the modified inversion solver. We study the sensitivity of two medium parameterizations and compare four inversion strategies on a canonical model. This code can provide better understanding of the Earth's subsurface in the rather common geological contexts in which seismic velocity displays a weak dependency on the polar angle of ray propagation.

In this study, we present seismo-hydromechanical results from six hydraulic fracturing experiments executed in the framework of the In-situ Stimulation and Circulation (ISC) project. The well-characterized and extensively monitored target rock allows for the study of (1) the response of the rock mass, (2) the injection and pore pressure response, and (3) the geometry of newly created fractures and their interaction with the natural fracture network.

In using dense geodetic networks and large GPS datasets, we are able to extract regionally coherent velocities and deformation rates in France and neighboring western European countries. This analysis is combined with statistical tests on synthetic data to quantify the deformation detection thresholds and significance levels.

We present an open-source software framework for fast and flexible forward modelling of seismic and acoustic wave phenomena and elastic deformation. It supports a wide range of applications across volcanology, seismology, and geodesy to study earthquakes, volcanic processes, landslides, explosions, mine collapses, ground shaking, and aseismic faulting. The framework stimulates reproducible research and open science through the exchange of pre-calculated Green's functions on an open platform.

An active CO₂ degassing site in the western Eger Rift, Czech Republic, was investigated with a 6.5 km long geophysical survey using a specific large-scale geoelectrical setup, supported by shallow geoelectrical surveys and gravity measurements. The experiment reveals unusually low resistivities in the sediments and basement below the degassing area of less than 10 Ω and provides a base for a custom geological model of the area for a future 400 m deep research drilling in this area.

Due to ice sheets and glaciers losing mass, and because continents get wetter and drier, a lot of water is redistributed over the Earth's surface. The Earth is not completely rigid but deforms under these changes in the load on top. This deformation affects sea-level observations. With the GRACE satellite mission, we can measure this redistribution of water, and we compute the resulting deformation. We use this computed deformation to improve the accuracy of sea-level observations.

Knowing the velocity with which seismic waves travel through the top of the crust is important both for identifying anomalies, e.g. the presence of resources, and for geophysical data evaluation. Traditionally this has been done by using empirical functions. Here, we use machine learning to derive better seismic velocity estimates for the crust below the oceans. In most cases this methods performs better than empirical averages.

The paper presents an alternative technique for estimating the Biot coefficient, which governs the partitioning of stresses between a porous skeleton and the saturating pore fluid of a fluid-saturated rock.

The controls on the 20 Myr old Burdigalian transgression in the Swiss Molasse basin have been related to a reduction in sediment flux, a rise in global sea level, or tectonic processes in the adjacent Alps. Here, we readdress this problem and extract stratigraphic signals from the Upper Marine Molasse deposits in Switzerland. In conclusion, we consider rollback tectonics to be the main driving force controlling the transgression, which is related to a deepening and widening of the basin.

By utilising both the observed gravity field of the Alps and their forelands and indications from deep seismic surveys, we were able to produce a 3-D structural model of the region that indicates the distribution of densities within the lithosphere. We found that the present-day Adriatic crust is both thinner and denser than the European crust and that the properties of Alpine crust are strongly linked to their provenance.

Western Pacific plate subduction played a key role in the late Mesozoic geologic evolution and volcanism in East Asia. New and published zircon U–Pb ages of extrusive rocks are compiled in SE China. Results show that the volcanism mainly spanned ~95 Myr (mainly 70 Myr, Late Jurassic–Early Cretaceous) and migrated northwest from the coast inland, implying the Paleo-Pacific Plate subducted northwestward and the roll-back subduction did not begin until the Aptian (~125 Ma) of the mid-Cretaceous.

In source regions of magmatic systems the temperature is above solidus and melt ascent is assumed to occur predominantly by two-phase flow. This two-phase flow allows for the emergence of solitary porosity waves. By now most solutions of these waves used strongly simplified viscosity laws, while in our laws the viscosity decreases rapidly for small melt fractions. The results show that for higher background porosities the phase velocities and the width of the wave are significantly decreased.

We use a 4-D numerical sensitivity study to investigate which geological parameters exert a dominant control on the quality of a deep geothermal reservoir. We constrain how the variability of these parameters affects the economic potential of a reservoir. We show that the interplay of high permeability and hydraulic gradient is the dominant control on reservoir lifetime. Fracture anisotropy, typical for faults, leads to fluid channelling and thus restricts the exploitable volume significantly.

This contribution describes a technique to automatically extract digitized fracture patterns from images of fractured rock. Digitizing fracture patterns, accurately and rapidly with minimal human intervention, is a desirable objective in fractured rock characterization. Our method can extract fractures at varying scales of rock discontinuities, and results are presented from three different outcrop settings. The method enables faster processing of copious amounts of fractured outcrop image data.

Convection in the deep Earth dynamically changes the elevation of plates. Amplitudes of those vertical motions predicted from numerical models are significantly higher than observations. We find that at small wavelengths (< 1000 km) this misfit can be due to the oversimplification in viscosity of rocks. By a suite of numerical experiments, we show that considering the non–Newtonian rheology of the mantle results in predictions in amplitude of dynamic topography consistent with observations.