The capacity of aqueous fluids to mobilize rare Earth elements is closely related to their molecular structure. In this study, first-principle molecular dynamics simulations are used to investigate the complex formation of yttrium with chloride and fluoride under subduction-zone conditions. The simulations predict that yttrium–fluoride complexes are more stable than their yttrium–chloride counterparts but likely less abundant due to the very low fluoride ion concentration in natural systems.

We analyzed reported oceanic earthquakes in Mexico. We used data from different agencies. By analyzing the occurrence of earthquakes, we can extract relevant information such as the level of seismic activity, the size of the earthquakes, hypocenter depths, etc. We also studied the focal mechanisms to classify the different types of earthquakes and calculated the stress in the region. The results will be useful to understand the physics of oceanic earthquakes.

Rocks in fault zones can melt during earthquakes. The geometry and magnetic properties of such earthquake-melted rocks from Jämtland, central Sweden, show that they formed during Caledonian mountain building in the Palaeozoic. The small sample size (~0.2 cm³) used in this study is unconventional in studies of magnetic anisotropy and introduces challenges for interpretations. Nevertheless, the magnetic properties help shed light on the earthquake event and subsequent alteration of the rock.

A shallow borehole was drilled to explore the petrophysical and hydraulic characteristics of a hydrothermally active fault in the crystalline Aar massif of the Alps. A key objective of studying surficial features of this kind is to establish analogies with natural and deep-seated engineered hydrothermal systems. A wide range of geophysical borehole logs was acquired, which revealed a complex fracture network in the damage zone of the fault and a related compartmentalized hydraulic behavior.

We perform a three-dimensional numerical study of the fluid–solid deformation at the pore scale. We show that seismic wave velocities exhibit strong azimuth-, angle- and frequency-dependent behavior due to squirt flow between interconnected cracks. We conclude that the overall anisotropy mainly increases due to squirt flow, but in some specific planes it can locally decrease as well as increase, depending on the material properties.

The Ligurian Sea opened ~30–15 Ma during the SE migration of the Calabrian subduction zone. Seismic travel time tomography reveals the absence of oceanic crust, documenting that the extension of continental lithosphere stopped before seafloor spreading initiated. The extension led to extreme crustal thinning and possibly exhumed mantle accompanied by syn-rift sedimentation. Our new interpretation of the crust's nature is important for plate reconstruction modelling related to the Alpine orogen.

This paper explores failure modes and deformation behavior of faults in the mechanically layered Eagle Ford Formation, an ultra-low permeability self-sourced oil and gas reservoir and aquitard in southwest Texas, USA. The role of dilation versus slip relates in predictable ways to mechanical stratigraphy, stress field, and dilation and slip tendency. We conclude that dilation tendency vs. slip tendency can be used to infer fault and fracture deformation modes and conduit versus seal behaviour.

The deep geothermal project in St. Gallen, Switzerland, aimed at generating electricity and heat. The fluid pumped into the underground caused hundreds of small earthquakes and one larger one felt by the local population. Here we use computer simulations to study the physical processes that led to the earthquakes. We find that gas present in the subsurface could have intensified the seismicity, which may have implications for future geothermal projects conducted in similar geological conditions.

Normal faults have irregular geometries on a range of scales. A quantitative model has been presented which illustrates the range of deformation arising from movement on fault surface irregularities, with fault-bend folding generating geometries reminiscent of normal drag and reverse drag. We show that fault throw can be subject to errors of up to ca. 50 % for realistic fault bend geometries (up to ca. 40°), even on otherwise sub-planar faults with constant displacement.

In this study, we conducted 3-D numerical simulations of fluid flow in synthetically generated fractures that statistically reflect geometries of naturally occurring fractures. We introduced a non-dimensional characterization scheme to relate fracture permeabilities estimated from the numerical simulations to their geometries in a unique manner. By that, we refined the scaling law for fracture permeability, which can be easily integrated into discrete-fracture-network (DFN) modeling approaches.

We investigate the size of mineral grains of Earth's rocks in computer models of the whole Earth. This is relevant because grain size affects the stiffness (large grains are stiffer) and deformation of the Earth's mantle. We see that mineral grains grow inside stable non-deforming regions of the Earth. However, these regions are less stiff than expected. On the other hand, we find that grain size diminishes during deformation events such as when surface material comes down into the Earth.

Data on CO₂ degassing help understanding the relations of the gas flow on geodynamic processes. Long-term gas flow measurements in rough field conditions present a challenge due to technical problems. We describe methods used for CO₂ flow monitoring in West-Bohemia/Vogtland, which is typical for high CO₂ flow, and present a new robust method based on pressure measurements in a water column. The results of 10 years of CO₂ flow measurements and their relation to seismic activity are discussed.

We apply three-dimensional (3D) thermo-mechanical numerical simulations of the shortening of the upper crustal region of a passive margin in order to investigate the control of 3D laterally variable inherited structures on fold-and-thrust belt evolution and associated nappe formation. The model is applied to the Helvetic nappe system of the Swiss Alps. Our results show a 3D reconstruction of the first-order tectonic evolution showing the fundamental importance of inherited geological structures.

Plate tectonics describes the creation, motion, and ultimate destruction of the Earth's continents and oceans. A key plate tectonic process is continental extension; this occurs when the Earth's plates are pulled apart to ultimately form a new ocean. Giant fractures (faults) accommodate plate stretching, although buckling (folding) is thought to be locally important. We use field data to understand how fracturing and buckling relate to each other, demonstrating they are spatially complex.

Integrated interpretation of multiple datasets is a key skill required for better understanding the composition and configuration of the Earth's crust. Geophysical and 3D geological modelling are used here to aid the interpretation process in investigating anomalous and cryptic geophysical signatures which suggest a more complex structure and history of a Palaeoproterozoic basin in Western Australia.

To describe permeability, a key parameter controlling fluid flows in the Earth’s subsurface, an accurate determination of permeability on the pore scale is necessary. For this reason, we sinter artificial glass bead samples with various porosities, determining the microstructure and permeability using both experimental and numerical approaches. Based on this we provide parameterizations of permeability, which can be used as input parameters for large-scale numerical models.

This paper shows the results of seismic interpretations that document the presence of large Upper Jurassic carbonate buildups in the Miechów Trough (S Poland). Our work fills the gap in recognition of the Upper Jurassic carbonate depositional system of southern Poland. The results also provide an excellent generic reference point, showing how and to what extent seismic data can be used for studies of carbonate depositional systems, in particular for the identification of the carbonate buildups.

Given the inconsistency of the plane height and also the effects of the initial density model on the inversion results, the sequential inversion of on-orbit GOCE satellite gravity gradient and terrestrial gravity are divided into two integrated processes. Some new findings are discovered through the reliable and effective inversion results in the North China Craton.